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3Delight 10.0 User`s Manual

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1. 36 IER LEE 29 options to demitif eee eee eee 21 options to bdri2tif eessen 22 options to renderdl cece eee eee eee 8 options to shaderdl 02 eee eee 11 options to tdlmake ssssssssseses 15 options implementation specific 34 options limits bucketsaize 37 options limits eyesplits 20000 34 options limits gridsize 2004 3T options limits othreshold 3r options limits texturememory 3T options limits texturesample ot options limits volumegroupsize 38 options limits zthresbold 38 options messages eene 41 options network cache 41 options rendering eee eee eee eee 34 options RIB output 0 0 2 eee eee 42 options search paths 00 cee eee eee 39 options searchpath cece eee ee eee 39 options shadow bas 34 options shadow sample 38 options standard 29 options statistics 2 eee eee 40 OpliOns Meer cbse Age eeh r AE EN othreshold RiOption eee 37 outline rendering 00 0000 150 output variables dynamic ss 118 outpultimg RB ee mee mete REIR 156 P parametric patches 00 e cece eee eee 55 EEN 55 particles height 0 2 e eee 56 particles aspect ratio 00 cee eee ee eee 56 particles m
2. 4 84 primitives procedural 0000 214 ProcDynamicLload ea err RR EEN 5T procedural geometry efficiency s eru 160 procedural primitiven 57 214 procedurals level of detail 154 procedurals multithreading 53 ProcRunProgram 6 cece eee eee eee 57 progress callback cre irii crissicereninii ortini 40 progressive hider option 33 PSD display driver 22 eee 175 psd tdlmake nr hme RR Re User 19 keelen pri d gene 26 DEIER iso neseret rperitent pev bbfgesiebeis 27 PUCVIEW oi Seed dine chi rerea eq e EQ 26 push resizable arras eee eee eee tl Q e EE 57 quality level of detail 154 R radiance lookup photonmaps 106 random Pall aere e ree Doneu wee ENEE OEE 78 range COMPLESSION ies occas ns ERNEIEREN ENEE dE 22 raster SPACE ZER etd es ade aes a bae REDE 66 rasterorient RiAttribute 0 52 ray labels ug ere Reg br rani shad pore cee 127 ray traced shadows 005 122 126 ray tracer biet asser rerhr Rr een 130 ray DEE 124 Concept Index ray tracing displaced geometry 128 ray tracing functions esses 95 ray tracing hider SEENEN 130 ray tracing anti aliasing s sserreree 129 ray tracing approximation 38 ray tracing derivatives 0 00 130 ray tracing maximum ray depth 38 ray tracing motion bur 46 raytrace Hider ssc
3. 0c eee 33 Implementation specific options and their default values 0 005 43 Standard RenderMan attributes and their default values 2 00005 44 Predefined class shader method 63 Supported color spaces 00 2 00 0000 eee cede eee case Rd et e EET EE Ra a 65 Predefined Coordinate Systems 0c cece eee eee eee eee 66 Valid category terms 5 26 e oer dE re dl UR deip eed e nese deena 75 Predefined Surface Shader Variables 0 0 cece eee ence ene e ees 85 Predefined Light source Variables seeleesseeee e 86 Predefined Volume Shader Variables 0 00 cece eee eee eee e nee tenes 87 Predefined Displacement Shader Variables 0 cece e ence een eee eens 88 Predefined Imager Shader Variables 0 0 cece cece eee eee een eens 88 Common optional parameters to ray tracing functions 000e ee eee 96 occlusion and indirectdiffuse optional parameters 102 Parameters controlling point based occlusion and color bleeding 103 subsurface optional parameterg sss en 105 caustic shadeop implementation using the photonmap shadeop 107 ptexture optional parameters 0 cece cece ene n ete tenes 108 texture shadow and environment optional parameters 109 bake3d optional parameters 0 cece eee ene reren 111 texture3d optional parameter
4. 54 creating brick maps 26 p 58 cubic environment maps 15 current Spa6e ioxmeeenk rm PERDERE POPE Y te 66 DUPIVOS hxc d serv x RNERA ee 55 D deep shadow maps 123 deep shadow maps advantages 123 251 deep shadow maps compressing bri deep shadow maps drawbacks 124 DELIGHT environment variable 5 depth filter 2 sess eer tr doesn Een 30 32 depth of field artifacts with motion blur 32 derivatives in ray racing 130 derivatives centered 00 cece eee eee 52 derivatives second 52 derivatives smooth 0 cece cece eee ee 52 dicing Cam ras ENEE ELS 153 diffusehitmode shading attribute 46 directory textures lesse 15 156 niu P 156 displacement shader stacking 49 displacement in ray tracing 128 displacement using dicing cameras with 153 displacementbound RiAttribute 49 display driver example ssssusse 202 display drivers cineon sssseessssss 173 display drivers DM TrA display drivers EPO 172 display drivers framebuffer 168 display drivers idisplay ssssssuese 168 display drivers DE 170 display drivers JPEO 0 cece eee 176 display drivers PIC 175 display drivers D n 175 display drivers shadowmap p display
5. cd downloads gunzip 3delight 3 0 0 Linux i686 libstdc 3 tar gz tar xf 3delight 3 0 0 Linux i686 libstdc 3 tar cd 3delight 3 0 0 Linux i686 libstdct 3 install prefix software cd software 3delight 3 0 0 unsetenv DELIGHT source 3delight_csh cd DELIGHT examples opacity shaderdl fonky sl renderdl cubits rib exit After typing those commands cubits tiff should appear in your directory Note that if you do not specify the prefix option to install 3Delight is installed in usr locall Finally you should add the following line to your Login file source software 3delight 3 0 0 3delight csh If you use bash then you should add source software 3delight 3 0 0 3delight bash l root permissions are required when installing in usr local Chapter 2 Installation 5 2 3 Windows On Windows systems simply run setup 3 0 0 exe Depending on the user s system privileges the installer will ask whatever is necessary to install 3Delight for either all users or for only the current user In both cases three different installations are possible Full Installation Installs everything needed to run 3Delight and all the files needed for development Minimal Installation Only installs files needed to run 3Delight includes all binaries Custom Installation User can choose exactly what is installed To unninstall 3Delight simply run Uninstall 3Delight in the start
6. 0 eee eee eee eee ee 41 midpoint filtering scele eese 32 midpoint shadow maps 123 midpointratio ider 39 minsamples occlusion parameters 102 motion blur artifacts with depth of field 32 253 motion blur in shadows 0005 123 motion blur particles eee ee 56 motion blur ray tracing 0 46 motion blur sampling ssseesesesese 31 motion blur shading ssusnussurrerrenua 53 ste Ree 31 multi camera ND 66 multi camera raster gpace eee 66 multi camera rendering s rrrrrrrerr 148 multi camera screen space 200 66 multi camera view dependent shading 46 multi processing command line options 8 multi thread command line options 8 Multiprocessing 02 e eee eee eee 120 multiprocessing licensing sscscerenene 122 multiprocessing load balancing 120 multiprocessing performance 122 multithreadimg s et Steg Sege teg eg 120 multithreading Dcensatng 122 multithreading performance 122 N name attributes cece eee eee eee eee 44 NDG space lucc t Be eee died 66 network cache 154 network cache options sssseeeeesess 41 network cache actvating 155 network cache cache directory permissions 156 network cache directory textures 156 network cache purging 005
7. 198 DspyImageClos86 p ee Sg T I her nes 194 DspylmageData defe SR Sege Rr ed even 194 DspyImageDelayClose sss 194 DspyI mage0pen seen 194 DspylImageQuery eee 194 DspyMemReverseCopy eese 199 DspyRegisterDriverTable 199 257 Depebeorderbormatting sess 198 D PC 91 DW ets aevo tv e tu ag V ees Rd a Edu epe e vdd 91 E environmehnt coccesey4eg is p SES sa d dudas 108 e EE 90 F PACeHOrwar EE 93 E GE 91 Le EE 117 e EE 90 formate cares sas eee adie Saeko 112 TE DEE 95 G PACKS secede tad date eddies gd Eet aq Rus 103 POtL Uh CEET 119 EGLIIghnLB8 osenreneehtenbe ca dune bier a ener 119 getslhader icecss i944 P ed ex RR RR 119 getshaderS ilossekiResi eR RD a de e ee 119 EE 119 EE 118 EE 118 Drreate urfaceboint sse 223 GxEvaluateSurface esses 223 Greeieonetrg cece cece eee eee eee 222 GxFreeSurfacePoint 0 00008 223 GxGetFaceCount esses 223 GxGetGeometry i ee eR RR RE UR EIER 222 DGetGeometraN eee eee eee ee 222 I ANCIENTS EE 114 KK EE d EE 99 100 Jeu v4 yu Reb Peri dE E Ee Ge 93 SE a EE 90 S NG EE 117 S NN 117 118 isshadowray epe ip Ses ee eke es Be CE 117 L MON EE 93 lightsOUrCe d eene nex eme e rne 114 logiciel rinde riche eua 90 M mnatclhi iewece genres sagt ee cu a pees Coe dI 113 Function Index jt ER 90 ILE o eeseberace Shh ded
8. It is important to note that there is an additional cost when using true geometric displacements in the context of ray tracing for the following reasons 1 SDelight needs more memory to hold displaced geometry even though it uses a caching mech anism to reduce memory allocations 2 Displacement bounds expand primitives bounding boxes this has a bad effect on ray tracer s space partitioner meaning less efficient ray primitive intersections It is clear that badly set displacement bounds or extreme displacement can make ray tracing of true displacements very costly 3 For many primitives geometrical intersections are less efficient than the analytical algorithm 3Delight uses for non displaced ray tracing D Refer to Section 5 2 5 displacement page 49 for more information Chapter 7 Rendering Guidelines 129 Figure 7 1 Raytraced displacements become necessary when silhouette details and self shadowing are important 7 3 6 Oversampling and Derivatives All ray tracing functions accept a parameter to specify the number of rays to trace Tracing many rays is the only way to perform spacial and temporal motion blur anti aliasing when using ray tracing Follows a table that shows for every ray tracing shadeop the default number of rays traced and how to modify the default behavior trace shadow environment transmisson Traces only one ray if samples is not specified The following exa
9. environment direction The direction pointing towards the center of the sampled region in the en vironment map Note that ray direction holds a randomized direction inside the region and this direction is suitable for sampling An example on how to use these variables is shown in Listing 7 5 pointcloud pointcloudfile Another special form of the gather construct can be used to gather points in a previously generated point cloud This is better illustrated in Example 6 1 Chapter 6 The Shading Language 81 Average 32 samples from a point cloud surrounding the current point using gaussian filtering Assume point cloud has been saved in object space point object P transform object P normal object N ntransform object N string category concat pointcloud texturename color surface color 1 sum color 0 float total atten 0 point position 0 float point radius uniform float radius 0 1 gather category object P object N PI 32 point surface color surface color radius radius point position position 1 float dist distance object P position dist 2 dist radius float gaussian atten exp 2 dist dist total atten gaussian atten Sum color gaussian atten surface color normalize final color sum_color total_atten Example 6 1 Using gather to access point cloud data As shown in the above example
10. messages float mindispbound 50 When a displacement bound is specified for an object and that object is displaced by far less than the specified value 3Delight emits an informational message This option controls the percentage below which the message is shown The default value causes it to be shown when an object uses less than half its displacement bound Network Cache Options 3Delight has a network caching system for texture files located on slow access media such as NFS and CD ROM drives Refer to Section 7 14 Network Cache page 154 for a detailed description Option Option Option Option Option Option netcache string cachedir Specifies a directory for data caching The directory should be locally mounted such as tmp 3delight_cache and should be dedicated solely to 3Delight Do not use tmp as a cache directory tmp 3delight_cache is a better choice netcache integer cachesize 1000 Specifies cache size in megabytes with one megabyte being 1024 Kbytes To fully take advantage of this performance feature specify a size big enough to hold many textures ideally all the textures used in a given scene netcache integer minfreespace 0 Specifies a minimum amount of free space in megabytes to leave on the drive where the netcache is located This can effectively reduce the set cache size netcache integer writecache 0 This can be set to 1 to enable write caching of the various
11. RiO0ption rib compression compression RI NULL Specifies a compression for RIB output The only supported compression is gzip This option must be called before RiBegin RiOption rib format format RI NULL Specifies the format of the output stream format can either be ascii or binary RiOption rib header onoff RI NULL Specifies if a header is written at the beginning of RIB output This option must be called before RiBegin onoff is a string and can be set to either on or off RiOption rib ident onoff RI NULL Specifies if ascii RIB output is to be formatted nicely onoff is a string and can be set to either on or off RiOption rib pipe fd RI NULL Specifies a file descriptor to be used when outputing RIB This option must be called before RiBegin Other Options ption licensing integer waitforlicense 1 When this option is set to 1 3Delight will wait for a license when none is available to render If the option is set to 0 3Delight will return immediately if no license is available and renderd will return an error code of 99 see renderdl return values page 10 This is useful when managing a renderfarm and other work could be scheduled instead of the waiting 3Delight process Option licensing integer holdlicense 0 By default 3Delight will get new licenses for every render and release them once the render is done This can be unde
12. The advantage of using such relative paths is of importance entire RIB directory structures can be moved elsewhere and still have correct archive paths DL SEARCHPATH DEBUG When this variable is set to an integer value 3Delight prints a trace of how it uses the search paths A value of 1 or higher displays the files found A value of 2 or higher displays every location in which a file is searched for A value of 3 or higher shows how the dirmap option see Search Paths page 39 is applied DL DUMP CORE When this variable is set 3Delight will not install its own signal handlers This means crashes will result in core dumps instead of a stack trace among other things This is only useful for debugging Chapter 3 Using 3Delight 7 3 Using 3Delight 3Delight is a collection of tools and a library Here is an overview e renderdl a RIB file reader This programs reads a binary or ASCII encoded RIB file and calls the renderer to produce an image e shaderdl a shader compiler The compiler can produce either object code shaders a DSO or 8 DLL or byte code shaders commonly called interpreted shaders e tdlmake a texture optimizer which reads a number of input image files and produces a TIFF optimized for the renderer The optimized file typically has a tdl extension e shaderinfo a utility that gathers information from compiled shaders e dsm2tif a utility to convert deep shadow maps into TIFFs e hdri2tif a dynamic
13. point rotate point Q float angle point Pt1 Pt2 Rotates a point Q around the line defined by Ptl and Pt2 by a given angle New point position is returned Note that angle is assumed to be in radians float area point Pt string strategy Returns length Du Pt Dv Pt which is approximately the area of one micro polygon on the surface defined by Pt The strategy variable can take two values shading Compute area of the micro polygon based on surface derivatives This will pro duce smoothly varying areas if smooth derivatives are enabled see Section 5 2 7 other attributes page 51 dicing Compute area of micro polygons using their geometry regardless of smooth derivatives If no strategy is supplied shading will be assumed vector faceforward vector N I Nref Flips N if needed so it faces in the direction opposite to I Nref gives the element surface normal if not provided NRef is set to Ng vector reflect vector I N Returns the vector which is the reflection of I around N Note that N must be of unit length vector refract vector I Nr float eta Returns the refracted vector for the incoming vector I surface normal Nr and index of refrac tion ratio eta Nr must be of unit length float depth point Pt Returns the normalized z coordinate of Pt in camera space Return value is in the range 0 1 O near clipping plane 1 far clipping plane Pt is assumed to be defined in
14. version uniform float 4 Returns Major Minor release 0 e g 1 0 6 0 versionstring uniform string Version expressed as a string e g 1 0 6 0 Table 6 22 rendererinfo field names uniform float rendererinfo string dataname output type result Returns information about the renderer The operation succeeds if dataname is known and the type is correct in which case 1 0 is returned Otherwise 0 0 is returned and result is unchanged The supported data names are listed in Table 6 22 float rayinfo uniform string keyword output type result Provides informations about the current ray Returns 1 0 if keyword is known and result is of the correct type Returns 0 0 on failure EXAMPLE Choose the number of rays to trace depending on current ray depth uniform float ray_depth rayinfo depth ray_depth samples trace_color max 1 samples pow 2 ray depth trace P Nr samples samples Name Type Description speculardepth uniform float Returns the specular depth of the current ray diffusedepth uniform float Returns the diffuse depth of the current ray shadowdepth uniform float Returns 1 0 if the current ray is a transmission ray 0 otherwise depth uniform float Returns the total depth of the current ray speculardepth di f f usedepth shadowdepth type uniform string Returns one of the following camera light for photons specular
15. cr 3 DerivO computes the following expression Du num Duv num Du denum T Doldenum Chapter 6 The Shading Language uniform float red random uniform float green random uniform float blue random Ci color red green blue 6 4 3 Geometry Matrices and Colors float xcomp point Pt float ycomp point Pt float zcomp point Pt void setxcomp output point Pt float x void setycomp output point Pt float y void setzcomp output point Pt float z Gets or sets the x y or z component of a point or vector float comp matrix M float row col Returns M row col void setcomp output matrix M float row col x M row col x float comp color c float i void setcomp output color c float i x Returns or sets the ith component of the given color point transform string fromspace tospace point Pt point transform string fromspace matrix M point Pt point transform string fromspace tospace vector V point transform string fromspace matrix M vector V point transform string fromspace tospace normal N point transform string fromspace matrix M normal N 92 Transforms a point vector or normal from a given space fromspace to another space tospace If the optional fromspace is not given it is assumed to be the current space Refer to Table 6 3 for the complete list of valid space names vector vtransform
16. current space normal calculatenormal point Pt Computes the normal of a surface defined by Pt Often used after a displacement operation on Pt Equivalent to Du Pt Dv Pt but faster float determinant matrix M matrix inverse matrix M matrix translate matrix M point Tr matrix rotate matrix M float angle vector axis matrix scale matrix M point Sc Basic matrix operations The angle parameter passed to rotate is assumed to be in radians Chapter 6 The Shading Language 94 6 4 4 Lighting color ambient Returns the contribution from ambient lights A light is considered ambient if it does not contain an illuminate or solar statement It is not available in lightsource shaders color diffuse vector Nr Computes the diffuse light contribution Lights placed behind the surface element being shaded are not considered Nr is assumed to be of unit length Light shaders that contain a parameter named uniform float __nondiffuse are evaluated only if the parameter is set to 0 Not available in lightsource shaders see Section 6 3 Predefined Shader Parameters page 89 color specular vector Nr V float roughness Computes the specular light contribution Lights placed behind the object are not considered Nr and V are assumed to be of unit length Light shaders that contain a parameter named uniform float __nonspecular are evaluated only if the parameter is set to 0 Not available in lightsou
17. i_values Predefined variable s values i varying Predefined variable s class optional True for varying false for uniform SxDestroyParameterList SxParameterList i_parameterList Destroys a previous constructed parameter lists SxShader SxCreateShader SxContext i context SxParameterList i paramList const char i_shaderName const char i shaderHandle Creates a shader in the specified context i context The context where the shader is created and to which it will belong Chapter 10 Developer s Corner 226 i_paramList The parameter list which contains the shader instance parameter values These are the values which will not change for different calls to the shader This parameter may be null if no list is needed i_shaderName The name of the shader file to load without the sdl part i_shaderHandle The name by which the shader will be referenced This should be null for shaders which you do not intend to use as co shaders unsigned SxGetNumParameters SxShader i_shader Returns the number of parameters declared for the specified shader unsigned SxGetPredefinedParameters SxShader i shader const char o names unsigned i maxNames Returns the number of predefined parameters needed by i_shader and fills o names with pointers to their names i_shader The shader of interest o_names An array that will be filled with the parameters names May be null when i maxNames is set to 0 i maxNames The
18. x has no class specification float sqr float x return x x float uniform sqr uniform float x return x x surface dummy float t 0 5 function will be inlined in uniform form Ci sqr t funciton will be inlined in varying form Ci sqr u this will not compile v is varying but uniform sqr expects a uniform argument Ci uniform sqr v More about functions in Section 6 1 7 4 Functions page 82 6 1 7 Constructs 6 1 7 1 Conditional Execution Similarly to many other languages the conditional block is built using the if else keyword pair if boolean expression statement else statement The bracketed else part is optional 6 1 7 2 Classical Looping Constructs There are the two classical looping constructs in the shading languag the for loop and the while loop Both work almost exactly as in many other languages C Pascal etc The general form of a for loop is as follows if expression boolean expression expression statement For example uniform float i for i20 i lt count i 1 1 loop body D Note that i is uniform This means that the loop counter is the same for all shading samples during SIMD execution Declaring loop counters as varying makes little sense usually Also note that it is not possible to declare a variable in the loop initializing expression The while loop has the following structure
19. 0 33 Each line is printed after a bucket is done rendering RiO0ption statistics progresscallback amp function ptr RI NULL This option only available through a direct RiOption call accepts a pointer to a function which will be called at each rendered bucket to indicate renderer s progress The function prototype and option call are as follows void RenderProgress float i progress void data t D RtPointer callback RtPointer amp RenderProgress RiO0ption statistics progresscallback amp callback RI NULL The i_progress parameter will hold a real value in the range 0 100 The function may be called from a different thread than the one which started the render RiO0ption statistics progresscallbackdata amp data BI NULL This option specifies the data parameter passed to the progress callback function set with the progresscallback above numberofbucketsrendered totalnumberofbuckets S Approximate since it is computed as follow Chapter 5 3Delight and RenderMan 41 Messages Options The following options can be used to control the output of various messages by 3Delight Option Option messages string filter This option allows some error messages to be filtered out It should be set to a comma separated list of unwanted error codes such as A2037 P1168 The values are not cumulative meaning that setting the option to will cause all messages to appear again
20. Display file driver exposure gain gamma quantize zero one min max dither amplitude filter filtername filterwidth xwidth ywidth Note that there are four values given to quantize compared to three when calling RiQuantize This extended syntax allows specifying a value for zero black whereas RiQuantize assumes this value to be 0 Using this fourth parameter colors are quantized using the following formula Chapter 5 3Delight and RenderMan 30 value round zero value one zero dithervalue value clamp value min max The filter parameter accepts all the same filters as RiPixelFilter but also zmin and zmax These are special filters as they also affect the compositing of visible surfaces only the frontmost surface with an opacity exceeding that specified by the zthreshold option is retained see zthreshold page 38 The samples are then filtered by always picking the value of the one with the smallest z over the filtering area for zmin greatest z for zmax These filters are useful for output variables which should not be composited such as surface normals or object identifiers Parameter float exposure 2 float quantize 4 float dither string filter float filterwidth 2 int associatealpha int matte int exclusive string subset string lightcategory Default Value RiExposure RiQuantize RiQuantize RiPixelFilter RiPixelFilter 1 Desc
21. P1057 invalid parameter passed to RiGeometricApproximation param The only valid parameters are motionfactor and focusfactor P1058 light source with handle lighthandle was already declared the original light remains active but is no longer accessible lightid is taken by another light source Since it will be reserved for the new light source the old one will not be accessible for subsequent Rillluminate calls P1059 invalid light handle lighthandle passed to Rillluminate lighthandle was not assigned to any light source P1060 invalid argument value shadingrate passed to RiShadingRate The given RiShadingRate is either 0 or negative P1061 invalid argument interpolation passed to RiShadingInterpolation RiShadingInterpolation only accepts constant or smooth as a parameter RI CONSTANT and RI SMOOTH respectively P1067 invalid argument to RiMotionBegin The error could only be triggered when using the C API Here is an example RiMotionBegin O RI NULL P1068 invalid polygon passed to RiPointsPolygons A polygon or hole must have at least three vertices P1080 RiNuPatch NURBS specified with inconsistent parametric min max values A max parametric value either in u or v is less than a min P1081 RiNuPatch NURBS specified with illegal uorder vorder uorder or vorder parameters specified to RiNuPatch is less than two P1082 RiNuPatch NURBS specified with invalid uknot vect
22. and xyz and the default is rgb Be careful when using xyz color space since it implies a RGB to XYZ conversion inside the display driver and RGB values are assumed to be linear so setting Exposure to 1 1 is essential Note that run length encoding of Radiance files is not supported EXAMPLE Write out a radiance file using XYZ colorspace Exposure 1 1 Quantize rgb 00 00 use floating point data Display hdri pic radiance rgb string colorspace XYZ Chapter 8 Display Drivers 174 8 12 OpenEXR display driver This display driver writes out ILM s EXR files using the half and float formats There is no need to install any external libraries to use this display driver Floating point input is requested for this display driver so the RIB should contain the following lines before the display driver is invoqued Quantize rgba 0 0 0 0 The following parameters can be specified to the EXR display driver uniform string exrcompression zip uniform string compression zip Specifies which compression to use Valid compression schemes are none Disable compression zip Enable deflate compression using the zlib library This is the default compression scheme zips Like zip but each scanline is compressed separately Compression is not as good but the files will load faster in some software uniform string exrlineorder increasing Specifies if the image is to be written in
23. b void RifPluginDelete RifPlugin i_plugin delete i_plugin Listing 7 17 Example of a simple Ri plug in filter In the constructor we initialize the default filtering mode to k_Continue which means that all ignored Ri calls simply continue their normal execution path Additionally we set the SphereV member of RifFilter to point to our function since we desire to compute sphere s area We also set m_area to zero since this is our sphere area counter Chapter 7 Rendering Guidelines 165 Execution When 3DELIGHT executes an Ri command it will first process loaded plug in filters Filters will be executed in the order they were loaded Here is a pseudo code of the renderer s first action when it executes an Ri command 00 while current filter 01 if current filter catches this Ri command 02 call filter s entry point for Ri command 03 return 04 else if current filter has the terminate flag 05 current Ri command is not processed by the filter and 06 the terminate flag is set exit skipping all remaining 07 filters in the chain 08 return 09 end if 10 11 current Ri command is not processed by the filter but the 12 continue flag is set so continue with other filters in the 13 chain 14 15 current filter next filter in chain 16 end while 17 18 continue execution with renderer s Ri command 19 Listing 7 18 Pseudo code explaining wh
24. break case SLO_TYPE_SHADER printf nil break default Function to print one parameter PrintOneParameter const SLO_VISSYMDEF parameter const Format i format const char storage Slo_StortoStr parameter gt svd_storage const char name parameter gt svd_name const char detail Slo_DetailtoStr parameter gt svd_detail const char type Slo TypetoStr parameter svd type unsigned arraylen parameter gt svd_arraylen bool is_array parameter gt svd_isarray if i format e ribout T Output a string suitable for RIB syntax if is array printf Declare s Z s 4sN Nn name detail type else printf Declare s s 4s Ad N Nn name detail type arraylen return else if i_format e_table printf s s 48 48 48 h0 name storage detail type parameter gt svd_spacename 0 parameter gt svd_spacename lt none gt arraylen Print all default values if is array 1 PrintDefaultValue parameter J else for int i 0 i lt parameter gt svd_arraylen i if i 0 printf Chapter 10 Developer s Corner 234 PrintDefaultValue S1o GetArrayArgElement SLO VISSYMDEF parameter i 27 printf n return assert i_format e_prman printf As N As hs 4s name storage detail type if is array 1 if arraylen 0 printf else
25. gamma texture mapping ssseeeeess 140 gather category illuminance 19 80 gather category pointcloud category 80 gather category samplepattern 78 gathering output variable 79 geometric EXPOSUFE 6 eee eee 130 geometric primitives 0 0 esee 54 geometry CUIVES 2 220 i cheng reet UR ER 55 252 geometry implicit surfaces sussrerrn 56 geometry INSTANCES cesse 58 geometry parametric patches 55 geometry points and particles 55 geometry polygons sssssseeeeeeseee 55 geometry procedural esses 57 214 geometry ouadrics eese 5T geometry subdivision surfaces 54 getting latest version 2 global illumination 0 02 130 graphic state propagation ssscerererer 7 gridsize RiOption 0 e eee eee eee 37 grouping ray tracing 128 PRA keeled pM ad eee A 222 H hair Bikttrribute eee eee eee ee 52 IS d HE 99 HDRI range compression sssrererceu 22 eeh E EE 22 hdri2tif option 22 height for patch particles ssessurucunu 56 hidden culling attribute susnusrurnurnun 46 hider maxvpdepth eee e eee eee 33 hider midpointratio eee eee ee 33 hider photon ee cece ee eee eee 39 132 hider progressive option 33 hider ray racer 130 lider rAytraGe csse a esee h
26. rgbagamma or gamma to specify the gamma and colorspace to specify the name of some particular color space For example tdlmake rgbagamma 1 7 1 8 1 7 1 0 trees tif trees tdl Will process the input image as if the gamma was 1 7 for red 1 8 for green 1 7 for blue and 1 0 for alpha the gamma similarly specifies one single gamma value for all channels for the input image The following sets the color space to sRGB tdlmake colorspace sRGB intput tif output tdl The actual implications of specifying a gamma or color space to tdlmake are the following e tdlmake will create correct mip maps by performing a proper linearization prior to filtering The resulting image will still be stored with its original gamma so it is identical in look to the input e tdlmake will store the gamma of the image using a special TIFF tag e The texture and environment shadeops will properly linearize values for filtering and will return linear space colors so that the lighting is correctly performed in linear space 7 6 Baking Baking is the pre computation of a costly shading operator into a texture map or a point cloud so that it can be reused in more than one render using efficient texture lookups Baking is generally desirable for costly ray tracing effects such as ambient occlusion and indirect illumination see Section 7 4 Global Illumination page 130 Before considering the baking approach one should be aware that e Baking makes the rend
27. tokenname is reserved by 3Delight Please use another name Some strings are reserved to 3Delight and cannot be used to name some resources such as cameras Please choose another name R5046 RiBlobby can t load plugin plugin error You specified an invalid plug in to RiBlobby The system error is returned as part of the error message common error is invalid path to the plug in R5047 RiBlobby can t find ImplicitFieldNew entry point in plugin plugin check for correct C linkage Every RiBlobby plug in must have a ImplicitFieldNew entry point that is correctly exported R5049 point cloud file ptcfile does not contain radiance for subsurface Make sure to bake the radiance channel into any point cloud file that is to be used with the subsurface shadeop Refer to Section 7 4 5 2 Two Pass Subsurface Scattering page 138 and subsurface shadeop page 104 R5050 Cannot run more than one licens free license at once errorcode Only one free 3Delight instance can be run at once on some given local network For example running 3Delight on a laptop which is connected to a school network could cause this error since some other user might run the free version of 3Delight as well The displayed error code at the end of the message can be used for troubleshooting and should be sent to us if you think that there are no good reasons to see this message R5051 importance parameter to rayinfo must be varying In an
28. 1 float roughness 1 color specularcolor 1 float Km 0 05 float power 5 float frequency 10 color dip_color color 7 0 2 varying float magnitude 0 public void displacement output point P output normal N 1 put normalized displacement magnitude in a global variable So that the surface method below can use it point PP transform shader P magnitude pow noise PP frequency power P Km magnitude normalize N N calculatenormal P public void surface output color Ci 0i 1 normal Nf faceforward normalize N I vector V normalize I color specular component specularcolor Ks specular Nf V roughness color diffuse component Kd diffuse Nf attenuate the specular component in displacement dips Specular component 1 magnitude 1 magnitude Oi Os Ci Cs Ka ambient diffuse component specular component Ci mix dip color diffuse component Ci 1 magnitude Ci Oi Listing 6 1 En example class shader computing both surface shading and displacement 6 1 2 Variable Types 6 1 2 1 Scalars All scalars in the RenderMan shading language including integers are declared using the float keyword As an example the following line declares two scalars and sets the value of one of them to 1 float amplitude 1 0 frequency Some notes about scalars Chapter 6 The Shading Language 65 e Sinc
29. 156 network cache safety 000005 156 network rendering 0 22 eee 121 network rendering settings esses 60 nsamples RiAttribute eee ee ee 47 nthreads render option 34 O Object instances eg AE Gre rer EE EE vest 58 el Oe EE 66 OCCHUISION A ENEE EES 130 occlusion baking 0 0c eee eee 145 occlusion shadeop parameters 101 occlusion occlusion parameters 102 offset camera sbutter 2c eee ee eee 36 one pass photon map generation 132 one pass photon maps 132 opacity Culling seier cer n Reeg d n deg get geg saad 37 opacity threshold 002 eee 37 optimizing renderings s rrerrrrr 159 option for shadow sampling 38 option licensing related 42 option photon emit 0 eee eee eee 36 option photon maxdiffusedepth ST option photon maxspeculardepth 3T option photon writemaps s s essrsrer 36 option render bucketorder 34 Concept Index option render nthreads sssuusuese 34 option render standardatmosphere 34 option render volumeshadingrate 35 option shutter efficiency 0045 36 option shutter offset 0 e eee eee eee 36 option trace approximation 38 option trace depthaffectsptc 39 option trace maszdenth 38 option trace specularthreshold
30. Dead code elimination Copy Propagation Constant Folding Arithmetic operations are reused if possible Removes code from loops or moves them outside when possible Generates extra code to force some non SIMD calls to become SIMD Converts varying variables to uniform variables when possible 03 This level enables even more aggressive optimizations We tend to put newly introduced optimizations in 03 and move them to 02 after they have been thoroughly tested Experimental optimizations which do not produce faster code in all cases are also put here Disables array bounds checking Removes empty and useless loops even if they are infinite Widens the scope of different optimizations This makes them more thorough at a cost of extra compilation time Chapter 3 Using 3Delight 14 Strict RSL Syntax The strict option to shaderdl disables some non standard syntax and semantics By default shaderd1 is quite permissive in order to be compatible with other RSL shader compilers By using this option the shader writer can write shaders that are more in line with the good practices of RSL programming Follows a list of features that are disabled by the strict option e Error instead of a wrning for varying strings Writing the following code would produce an error varying string bad something e Error when accessing pre defined variables without the extern keyword The following surface will print an error in s
31. For example Display super_render framebuffer rgb provides framebuffer in drivername filename Gives the filename provided in the Display command For example Display render tif tiff rgb provides render tif in filename width height Gives the resolution of the image in pixels If the image is cropped width and height reflect the size of the cropped window paramcount Indicates total number of user parameters provided in this call UserParameter An array of user parameters of size paramcount UserParameter is defined as typedef struct const char name char valueType valueCount const void value int nbytes UserParameter name is the name of the parameter valueType is its type which can be one of the following i for an integer type f for an IEEE floating point type s for a string type and p for a pointer type valueCount is used for parameters that have more than Chapter 10 Developer s Corner 196 formatcount formats flags one value such as matrices and arrays value is the pointer to the actual data except for the p type where it is the data itself A set of standard parameters is always provided those are described in Table 10 1 Number of output channels An array of channel descriptions of size formatcount A channel description contains a name and a type typedef struct 1 char name unsigned type PtDspyDevFormat The type can take one of the
32. N float eta output float Kr Kt output vector R T Uses the Fresnel formula to compute the reflection coefficient Kr and refraction or transmis sion coefficient Kt given and incident direction I the surface normal N and the relative index of refraction eta Note that eta is the ratio of the index of refraction in the volume containing the incident vector to that of the volume being entered a ray entering a water volume from a void volume would need an eta of approximately 1 0 1 3 Here is a noteworthy quotation from The RenderMan Companion In most cases a ray striking a refractive material is partly reflected and partly refracted The function fresnel calculates the respective fractions It may also return the reflected and refracted direction vectors so that is subsumes refract If R and T are supplied they are set to the direction vector of the reflected and the transmitted refracted ray respectively 6 4 5 Ray Tracing 6 4 5 1 Common Parameters All the ray tracing shadeops can receive a number of common optional parameters these are de scribed in Table 6 10 Specific optional parameters are described with each shadeop individually Chapter 6 The Shading Language 96 Name label subset bias hitmode hitsides raytype raypruning weight Type Default uniform string K uniform string a uniform float 1 uniform string default uniform string default uniform
33. Rendering Guidelines 125 occlusion A shadeop to render ambient occlusion effects This will intersect with objects visible to transmission rays The calling syntax is described in occlusion shadeop page 99 indirectdiffuse A shadeop to render color bleeding effects This will intersect objects visible to reflec tion rays Can be used to implement the final gathering algorithm when combined with photon maps as explained in Section 7 4 3 Final Gathering page 133 The calling syntax is described in indirectdiffuse shadeop page 99 In practice this function is deprecated in favor of the much more advanced trace gather A general construct to sample the scene using ray tracing and to sample HDR images This will interesect objects visible to reflection rays The calling syntax is described in gather shadeop page 103 H 7 3 1 Reflections and Refractions Using the trace shadeop is the simplest way to compute reflections and refractions although existing shaders need to be modified Shaders that use environment can perform ray tracing without any code modifications by providing raytrace as the environment map name A shader that can be enhanced in this way is the standard shinymetal Note that geometry does not appear in ray tracing unless it is visible to the right type of rays For environment this is accomplished using Attribute visibility int specular 1 When computing reflection or refractions on c
34. RslContext rslContext int argc const RslArg argv RslPointIter retArg argv 0 RslPointIter argi argv 1 unsigned numVals RslArg NumValues argc argv for unsigned i 0 i lt numVals i xretArg 0 argi 0 arg1 0 retArg 1 argi 1 arg1 1 xretArg 2 argi 2 arg1 2 t retArg arg1 J return 0 void plugin_init RixContext context This is an initialization function for the entire plugin shadeop specific functions can also be specified in the pluginFunctions array below void plugin_cleanup RixContext context Chapter 10 Developer s Corner 211 This is a cleanup function for the entire plugin shadeop specific functions can also be specified in the pluginFunctions array below extern C static RslFunction pluginFunctions float sqr float float_sqr NULL NULL point sqr point point_sqr NULL NULL NULL h RSLEXPORT RslFunctionTable RslPublicFunctions pluginFunctions plugin init plugin cleanup Here is how to compile a DSO under different environments Linux g shared o sqr so I DELIGHT include sqr cpp IRIX CC shared o sqr so I DELIGHT include sqr cpp MacOS X g dynamiclib o sqr so I DELIGHT include sqr cpp Windows cl I DELIGHT include LD sqr cpp When dealing with string parameters 3Delight provides the plug in with pointers which are valid at leas
35. RtString i fileName RtInt i nPoints RtInt i firstChannel const RtPoint i PO const RtPoint i P1 const RtPoint i P2 const RtPoint i P3 RtFloat Zo result RtInt RxTexturePoints4 RtString i fileName RtInt i nPoints RtInt i firstChannel RtInt i nChannels const RtFloat i SO const RtFloat i t0 const RtFloat i_s1 const RtFloat i t1 const RtFloat i_s2 const RtFloat i t2 const RtFloat i_s3 const RtFloat i t3 RtFloat zo result These functions are the same as the previous three except that they take four points to explicitely specify the filtering area Chapter 10 Developer s Corner 220 RtInt RxEnvironment RtString i fileName RtInt i firstChannel RtInt i nChannels RtPoint i dirO RtPoint i diri RtPoint i dir2 RtPoint i dir3 RtFloat Zo result RtInt RxShadow RtString i fileName RtInt i firstChannel RtPoint i PO RtPoint i P1 RtPoint i P2 RtPoint i P3 RtFloat Zo result RtInt RxTexture RtString i fileName RtInt i firstChannel RtInt i nChannels RtFloat i eg RtFloat i tO RtFloat i si RtFloat i t1 RtFloat i s2 RtFloat i t2 RtFloat i s3 RtFloat i t3 RtFloat o result These functions perform a single lookup at a time and do not provide automatic derivatives They are present for compatibility and should not be used in new code when there are several lookups to perform Using the Points version instead 10 2 1 3 Transformation functions There is a single space transforma
36. This can be used to trace transmission rays for to obtain blurry shadows environment color The color coming from the current environment direction This is the average color of the luminous cluster This is better illustrated in Listing 7 5 Assuming that envmap contains the name of the environment map kocc containts the shadowing strength envspace is the space in which the environment is string gather cat concat environment envmap color envcolor 0 vector envdir 0 raydir 0 float solidangle 0 gather gather cat 0 0 0 samples environment color envcolor ray direction raydir environment direction envdir environment solidangle solidangle 1 raydir vtransform envspace current raydir envdir vtransform envspace current envdir color trs transmission Ps Ps raydir maxdist bias bias trs 1 kocc 1 trs Cl envcolor trs Listing 7 5 Using gather to extract lighting information from environment maps Thanks to the special gather construct shown in Listing 7 5 it becomes easy to compute image based lighting transmission rays are traced into the scene to compute the shadowing and the color given by environment color is used directly to compute the environment color It is recommanded to combined the environment light with surface s BRDF to obtain more realistic results If one wants the diffuse environmen
37. amp table Where MayaDspyImageOpen etc are the same functions which would be used for a standalone display driver 10 1 1 3 Accessing 3Delight s Deep Buffer Contrary to a standard framebuffer which stores the final color at each pixel a deep buffer stores a list of surfaces touching a specific pixel 3Delight provides access to such a buffer with a notable difference surface lists are provided per sub sample and not per pixel This means that the user has access to the raw unfiltered surface lists directly from the render engine The surface lists which are called fragment lists in 3Delight can be accessed using a display driver By default all display drivers receive pixels and not fragment lists To enable fragment lists one has to reply consequently to the PkCookedQuery query as described in DspyImageQuery page 194 If this is done the display driver will receive the requested lists of fragments instead of a buffer of pixels The fragments are received through a PtDspyRawData structure The structure is shown in Listing 10 1 Chapter 10 Developer s Corner 200 typedef struct char ID 4 Samples per pixel in x amp y unsigned sppx sppy Data width amp height in pixels int width height Array of fragment lists NumLists width height sppx sppy PtDspyFragment fragments PtDspyRawData Listing 10 1 PtDspyRawData structure description Listing 10 2 illustrates how to get
38. color irradiance Section 7 4 5 2 Two Pass Subsurface Scattering page 138 Like filename but allows several point cloud files to be used together Specifies the coordinate system where the points in the point cloud are to be interpreted The default is world and this has no effect if filename is not used Specifies the reduced scattering coefficient when operating in point cloud mode Specifies the absorption coefficient when operating in point cloud mode Specifies the diffuse mean free path when operating in point cloud mode Specifies albedo reflectance when operating in point cloud mode Specifies the index of refraction when operating in point cloud mode Specifies the object scale when operating in point cloud mode May enable smoother results when the point density is too low for the amount of desired scattering 0 disables the smoothing and 1 enables it Values smaller or greater than 1 may also be used to control the amount of smoothing The subsurface approximation assumes that the surface topol ogy is that of a flat surface Very different geometry can give incorrect results Setting this parameter to 1 will enable an attempt to correct for this Specifies which channel of the point cloud is used as the area of samples Default is area Specifies which channel of the point cloud is used as the radiance of samples Default is radiance t or the first color channel if the one specified is not found Sp
39. cross fade between the provided models so that the transition between two different levels of detail remains smooth As with other features such as motion blur and depth of field level of detail quality depends on the oversampling used specified using RiPixelSamples the higher the oversampling the smoother the transtion between detail levels will be When used correctly level of detail can provide signficant savings in terms of memory use and rendering time it is important however to get things right 1 Only use level of detail for complex models that can be visualized at different sizes Crowds hair patches and trees are good candidates for level of detail rendering 2 Specify a correct bounding box with RiDetail This enables the renderer to estimate correctly which model is needed for a particular screen size 3 Use procedurals such as RiDelayedReadArchive to specify the models This avoids loading models that are not needed for some particular detail level AttributeBegin Detail 1 1 11 11 DetailRange 0 O 10 20 Procedural DelayedReadArchive tree simple rib 1 1 1 1 1 1 DetailRange 10 20 120 130 Procedural DelayedReadArchive tree medium rib 1 1 1 1 1 1 DetailRange 120 130 1e38 1e38 Procedural DelayedReadArchive tree complexe rib 1 1 1 1 1 1 AttributeEnd 4 Transitions between levels of detail must be as fast as possible This means that values provided by different RiDetail
40. dspytiff page 169 8 6 The zfile display driver A zfile contains depth information for each pixel in the image and is meant to build a shadow map The format of a zfile is described in Table 8 2 Chapter 8 Display Drivers 171 Offset Type Name Description 0 int32 magic Typically 0x2f0867ab Reading Oxab67082f means that swapping endianness in the entire file is necessary 4 short xres The x resolution in pixels 6 short yres The y resolution in pixels 8 float 16 Np World to Normalized Device Coordinate transforma tion matrix in row major order 72 float 16 NI World to Camera matrix in row major order 136 float xres yres z data Top to bottom left to right ordering Table 8 2 zfile file format To build a shadow map using a zfile use tdlmake shadow as described in Section 3 3 Using the texture optimizer page 15 or issue a RiMakeShadow command in a RIB file 8 7 The shadowmap display driver Use this display driver to create shadow maps without passing by a zfile Shadow maps in 3Delight are normal TIFFs The following parameter can be passed to this display driver uniform string zcompression lzw zip none Enables or disables compression Disabled by default integer aggregate 0 By default the shadowmap display driver will overwrite the shadow map if it already exists Setting this parameter to 1 will cause the display driver to concatenate the currently generated shadow map to t
41. filename has modification time in the future it will not be cached The file has an incorrect modification time This prevents proper operation of the netcache and should be fixed T2372 netcache more than one source for output file filename only one will be cached This is typically caused by more than one display having the same target T2373 cannot read 3D texture file filename message The renderer is unable to open the specified file The 3D texture file is either a point cloud file or a brick map file T2389 error estimating light contribution for photon generation 3DELIGHT was unable to properly spread photons between lights Photon map quality may be suboptimal T5061 Can t access directory where MARI textures are for file mari texture name tdlmake is trying to find MARI textures but is unable to list the files in the containing directory Chapter 10 Developer s Corner 194 10 Developer s Corner 10 1 3Delight Plug ins 10 1 1 Display Driver Plug ins 3Delight comes with a set of standard display drivers that are suitable for most applications see Chapter 8 Display Drivers page 168 However it is possible to write custom display drivers if some specific functionality is needed Basically a display driver is a dynamic shared library DSO or DLL in short which implements an interface that 3Delight understands This interface along with all the data types used is described in the DELIGHT include ndspy
42. float sqrt float x Returns the square root of x The domain is 0 in finity If x lt 0 this shadeop will return 0 float inversesqrt float x Returns 1 0 sqrt x The domain of this function is 0 infinity If x lt 0 this shadeop will return in finityl float pow float x y Returnx x y float exp float x Returns pow e x the natural logarithm of x float log float x base Returns the natural logarithm of x If the optional base is specified returns the logarithm of x in the specified base The domain of this function is 0 infinity If x lt 0 this shadeop will return in finity float sign float x Returns e lifzc O0 e lifx gt 0 float mod float x y Returns x modulus y More formally returns a value in the range 0 y for which mod z y x n y for some integer n float abs float x Returns the absolute value of x float floor float x float ceil float x float round float x type min type x y type max type x y type clamp type x min max min and max take two or more arguments of the same type and return the minimum and maximum values respectively clamp will return min if x is smaller than min max if x is greater than max and x otherwise type can be a float or a 3 tuple When running on 3 tuples these shadeops will consider one component at a time eg min point 1 2 3 point 4 3 2 will return point 1 2 2
43. it is compilable on all supported platforms see Section 10 3 linking with 3delight page 244 Chapter 10 Developer s Corner J kokokokokokokokokokokoke COCO COCCI kk kk GGG ICICI ICCC AGI AIK ak kk kak ak ak ak ak Copyright c The 3Delight Team All Rights Reserved DRO OOOO OO OR I A A I A a 2k 2k 24 4 3 2k 2k 24 24 3 2k 2k 2k 2k 2 2k 2k d eer VERSION Revision DATE RELEASED Date RCSID Id zeen include slo h include dlMsgShaderInfo h include dlVersion h include lt string h gt include lt stdlib h gt include lt stdio h gt include lt assert h gt typedef enum 1 e prman 1 e ribout e table e source e annotations e methods Format void PrintDefaultValue const SLO_VISSYMDEF arg 1 switch arg svd type 1 case SLO TYPE SCALAR printf Ag arg gt svd_default scalarval break case SLO TYPE STRING printf 4s arg gt svd_default stringval break case SLO TYPE POINT case SLO TYPE COLOR case SLO TYPE VECTOR case SLO TYPE NORMAL printf Ag g g arg gt svd_default pointval gt xval arg gt svd_default pointval gt yval arg gt svd_default pointval gt zval break case SLO_TYPE_MATRIX unsigned i 0 232 Chapter 10 Developer s Corner 233 void for i lt 15 i printf Ag arg gt svd_default matrixval i printf ien arg gt svd_default matrixval i
44. much of a difference 7 1 3 Network Rendering The P and p options start processes on the local machine only if rendering on many hosts is desired then renderdl should be provided with a list of usable machines through the hosts option But before using the remote rendering feature it is essential that the following points are checked Properly configured rsh or ssh By default Delight uses rsh to start a rendering process on remote machines this means that the machine that starts the render should have the required permissions on all used remote hosts If rsh is judged insecure one could use SSH by providing renderdl with the ssh option But this requires passwordless SSH authentication and requires more setup than the rsh method 3Delight must be executable from each rendering machine This should be the case if the package is installed on a NFS drive Note that it is impor tant that the cshrc or tcshrc file contain all the environment variables necessary to run 3Delight An easy way to verify that everything is setup properly on a remote machine is to invoke rsh or ssh manually 4 rsh hostname renderdl somefile rib The RIB file should be accessible from each remote machine This means that the RIB should reside on a shared drive such as a NFS drive Once everything is setup properly one can perform network rendering using the hosts option For example to compute an image using four machines the current machine origi
45. normal Nf faceforward normalize N I vector V normalize I uniform string raytype unknown rayinfo type raytype if raytype subsurface no specular is included in subsurface lighting Ci Ka amient Kd diffuse Nf else Ci subsurface P Ks specular Nf V roughness H Listing 7 6 Simple subsurface shader 7 4 5 2 Two Pass Subsurface Scattering One disadvantage of using the one pass method for subsurface scattering is that the pre computation performed by the renderer is not re usable from frame to frame This can be fixed by using a two pass technique that relies on a point cloud file to store the intermediate color values e In the first pass the frame is rendered normally as a beauty pass and the result is saved in the _radiosity channel of a point cloud file if needed the area of the micro polygon can be altered by using the _area float channel It is important to correctly set the culling attributes so that hidden surfaces are rendering as explained in Section 7 6 Baking page 141 e In the second pass the subsurface shadeop see subsurface shadeop page 104 is called by Chapter 7 Rendering Guidelines 139 specifying the point cloud file along with the subsurface parameters and is normally blended with the direct illumination as in the one pass method The two pass method is better illustrated using a simple example Projection pe
46. specifying pointcloud filename as the category to gather will give access to the following variables point position Position of the currently processed point point normal Normal of the currently processed point point radius Radius of the currently processed point point varname Any variable stored in the point cloud Note e Points from the point cloud will be listed in gather O from the closest to the furthest relatively to the provided position P e There is no guarantee that the actual number of points listed will be equal to the number of points requested This can happen for example if there are not enough points in point cloud still unlikely or the provided radius limits the total number of points available in a certain position Chapter 6 The Shading Language 82 e Points outside the radius can still be listed if their extent is part of the gather sphere points in a point cloud are defined by a point and a radius e The N and angle parameter provided to the point cloud version of gather are not considered gather accepts many optional input parameters and these are all explained in Table 6 10 Ad ditionally gather accepts the distribution parameter to sample arbitrary distributions this parameter is described in Table 6 11 gather also supports the samplebase parameter as described in Table 6 11 The next code snippet illustrates how to use an environment m
47. transmission 45 Attri Deg PEPERIT 44 attributes global illumination AT attributes grouping membership 44 attributes grouping tracesubset 44 attributes identifier name 44 attributes ray tracing 0000 45 attributes subsurface scattering 48 attributes visibility 00 45 automatic shadows ec cece eee eee 46 avoiding shadow bas 32 axis occlusion parameters sssssese 102 B backfacetolerance RiAttribute 51 backfacing culling attribute 46 backward message passing sssssssse 75 bake3d optional parameters 110 baling ieerv eR LR S erite SEA 141 baking TEE 110 baking in binary format 110 b kiug in 2D e ceto rr Re Pax 142 baking MSD rreren e Eet Aer 142 baking into brick maps 143 baking using light sources s uesuurusne 143 bias ray tracing attribute srsrrrrue 46 bias RIO pti OD ed t Se EELER nE nna 34 bias shadow eee eee eee eee eee ee 123 binary bake file format 110 Concept Index binary ER iit blobbies ide esessateererr e perire sce cece 56 bokeh shape control eee e eee eee 31 brick map creation using ptc2brick 26 bucketorder Hien 34 bucketsize Hien 3T C cachedir RiOption 0 00 e eee eee eee 41 callb
48. type can be either a float or a color If no texture coordinates are provided s and f are used An optional channel can be specified to select a starting channel in the texture This can be useful when a texture contains more than three channels Use tdlmake to prepare textures for improved performance and memory usage see Section 3 3 Using the texture optimizer page 15 texture accepts a list of optional parameters as summarized in Table 6 16 EXAMPLE Sharper result width 1 color c texture grid tdl s t width 0 8 Returns the green component float green texture grid tdl 1 Returns the alpha channel or 1 0 opaque if no alpha channel is present float alpha texture grid tdl 3 fill 1 0 Returns an _unfiltered_ color from the texture color unfiltered texture grid tdl s t s t s t s t Note that this shadeop will return proper linear space colors if the texture has a gamma specification Refer to Section 7 5 Texture Mapping in Linear Space page 140 for details The texture shadeop also includes support for MARI s UDIM tile mapping Simply provide a file name with the string UDIM in it and that will be replaced by the 4 digit tile number before looking for the texture Chapter 6 The Shading Language 108 type ptexture string texturename uniform float channel float faceindex type ptexture string texturename uniform float channel floa
49. 0 7 9 Display Subsets 3Delight can renderer an arbitrary number of the so called secondary displays Each secondary display can be fed with certain variables from shaders attached to the geometry This is handy to output many different variables for later compositing or number crunching But what if one wants to have different geometry not only output variables in each display This functionality is 4 Not the case when using the raytrace hider Chapter 7 Rendering Guidelines 149 achieved using the grouping membership attribute and the special string subset parameter that is accepted by RiDisplay The operation is summerized in two steps a Put geometry in groups that reflect the wanted separation This can be done using Attribute grouping membership groupname This attribute is further described in Section 5 2 1 primitives identification page 44 b To render a particular group in a particular display use the subset special parameters Display layer tif tiff rgb string subset groupname Note that it is exactly the same attribute as used for trace group memberships as explained in Section 7 3 4 Trace Group Membership page 128 One can combine many groups together as in Display layer tif tiff rgb string subset group1 group2 Or exclude particular groups as in Display layer tif tiff rgb string subset group3 The display subset feature would be incomplete
50. 10 Developer s Corner 243 nearest No interpolation nearest grid vertex is used linear Linear interpolation between surrounding grid vertices cubic Cubic interpolation between surrounding grid vertices exact No interpolation the grid is ignored and the exact value is com puted directly by the grid s shaders very expensive meant for low resolution testing only This function returns a varying float which is an identifier for the newly created ray This identifier can then be passed to VolumeTracer_StepRay_Function float VolumeTracer_StepRay varying float rayID output varying float length float VolumeTracer_StepRay varying float rayID output varying float length output varying float attributes Advances one step along a ray in SIMD and returns the volume s attribute midway along the step All rays must belong to the same grid Parameters are rayID Identifier of a ray previously created with VolumeTracer_InitRay length The length of this step attributes optional The volume s attributes computed near midpoint along the current step using the shaders specified to VolumeTracer_InitGrid and the interpolation mode specified to VolumeTracer_InitRay This function returns a varying float which indicates the fraction of the distance between the ray s start and end points that was covered until now When 1 0 is returned the end point has been reached and the ray cannot be advanced anym
51. 19 shadeops geometrw eee eee eee 92 shadeops lighting 0000 94 shadeops mathematics 89 shadeops message passing and information 113 shadeops noise and random 91 shadeops ray racing 95 shadeops sting 112 shadeops texture mapping 107 shader compilation 00 00 ee eee eee 11 shader evaluation ap 224 shader objects cele eerte ewes ead ew sus 62 shader apace eee cece eee eee eee e 66 shader structure rel 62 shad rdl ctiiohinesiedesiddia di EO EES abd df shaderdl optimizations 0 000 13 shaderdl Options ee EEN NENNEN ree 11 shaderdl predefined macros 13 shaderinfo command line options 23 shaderinfo source Code 232 shaderinfo tabular output format 23 shaders annotations cece ee eee 245 shading language predefined variables 84 shading rate sub surface scattering 137 shadingmodel photon seeesssseee AT shadingrate attribute 00 53 shadingrate BiAtrtritbute sess 47 Concept Index Shadow bias me n epe tmp SNE 123 shadow bias avoiding s ssssrrrrurirrrene 32 shadow map file format 171 shadow 1maps aoe os ee ee rer eid KEE en 122 shadow maps advantages cscscsreru 123 shadow maps COMpressing ssssrcrcrces 171 shadow maps drawbackes 123 shadow maps framing ssss
52. 1e38 which in practice means that there is no maximum distance for intersections string distribution This parameter specifies which BRDF trace will use to gather light from the scene The possible values are uniform cosine oren nayar blinn ashikhmin shirley cook torrance and ward The default value is uniform Each distribution requires some specific additional parameters listed below See also the bsdf shadeop page 95 which allows the same distributions to be used in an illuminance loop with direct light float samplecone Specifies an angle in radians which together with Pt and R describes a cone in which trace will gather light The angle specified is the cone s half angle meaning PI 2 will sample a hemisphere This applies to the uniform and cosine distributions The default value is 0 vector wo This vector specifies the viewer direction for the oren nayar blinn ashikhmin shirley cook torrance and ward distributions This is typ ically I Note that when this parameter is needed the R parameter is expected to be the surface normal float roughness Specifies the roughness of the surface for the oren nayar blinn ashikhmin shirley cook torrance and ward distributions The valid range is between 0 and 1 except for oren nayar which has no upper limit in practice there is little difference above PI 2 float roughnessv Specifies the roughness in the second axis for the anisotropic ashikhmin shirley and ward distri
53. 2 6 Co Shaders Co shaders are both a variable type and an abstract concept defining a modular component Co shaders are declared in a shader using the shader keyword and can be loaded using special co shader access functions as detailed in Section 6 4 9 Co Shader Access page 119 For example shader specular_component getshader specular_instance if specular_component null Ci specular_component gt Specular roughness Ks Declares a specular component shader variable and uses it to load and execute the specular_instance co shader which could be a Blinn or a Phong specular model depending on the co shader The co shader has to be declared in the scene description using the RiShader call Member variables in a co shader can be accessed using getvar method float Ks has Ks will be set to 0 if no Ks variable is declared in the co shader Also note that the last output parameter Ks can be omit ted in which case getvar serves to check the existence of the target member variable float has_Ks getvar specular_component Ks Ks The arrow operator can be used instead of getvar to access a member variable in a more compact way Ks specular component Ks The difference with getvar is that 3Delight will print a warning if the variable is not declared in the target co shader Additionally the arrow operator will only access variables in a read only mode and cannot be used to write into variables th
54. 250 Function MACK wi Sie keh bee P Rex ebe Re bla ere BE 257 List of Pigntes A tb NA Ee Ate LT TO A 260 vi Chapter 1 Welcome to 3Delight 2 1 Welcome to 3Delight 3Delight is a fast high quality RenderMan compliant renderer 3Delight comes as a set of command line tools and libraries intended to help you render production quality images from 3D scene descrip tions At the heart of the rendering tools is the Delight rendering engine This engine implements a fast scanline renderer coupled with an on demand ray tracer This combination allows 3Delight to render images quickly while giving you the ability to easily incorporate ray tracing effects whenever you need them 3Delight was first released publicly in August 2000 Since then numerous releases both public and internal have contributed to making it a stable renderer with strong features In the process special care has been taken to make sure 3Delight keeps its performance edge Check regularly at http www 3delight com for the latest release of 3Delight 1 1 What Is In This Manual The rest of this chapter gives an overview of the main features of the 3Delight rendering tools The installation procedure and insights about 3Delight s working environment are given in Chapter 2 Installation page 4 The complete list of provided tools and libraries along with operational details is given in Chapter 3 Using 3Delight page 7 RenderMan compliance and 3Delight specifi
55. 4 1 antwidth 0 2 uniform string type sphere AttributeEnd WorldEnd Listing 5 1 Using sphere shaped RiPoints 5 3 6 Implicit Surfaces Blobbies RiBlobby is implemented It supports spheres and segments All standard operators are supported including ad d subtract min max multiply divide and negate Variables specified to RiBlobby are interpolated over the resulting isoparametric surface by blending Note that vertex and varying variables are specified per node uniform variables are specified for the entire primitive 3Delight uses an adaptive algorithm to render implicit surfaces meaning that only small parts of the primitive and should b are tessellated at a given time Tessellation resolution is controlled by RiShadingRate e decreased if very small implicit surfaces in raster space are rendered In addition Repulsion planes are not supported yet Chapter 5 3Delight and RenderMan 57 setting RiShadingInterpolation to smooth the default greatly improves the rendering quality of implicit surfaces 5 3 7 Quadrics All six quadrics plus the torus are supported This includes RiSphere RiDisk RiHyperboloid RiParaboloid RiCone RiCylinder and RiTorus Each of these primitives accept the following variable types constant uniform varying and vertex Note that vertex variables behave exactly as varyings on quadrics 5 3 8 Procedural Primitives Procedural primitives
56. If no coordinate system is specified then the object space is used Do not forget to specify a displacement bound when using displacement shaders displacementbound float sphere radius matrix transform matrix This is very similar to the previous attribute except that the coordinate system is specified using a matrix bound float displacement radius This is provided for backward compatibility and specifies a sphere of a given radius living in the object s coordinate system trace int displacements 0 If true 11 objects are displaced prior to ray primitive intersection tests See Raytracing Displacements page 128 trace float displacementshadingrate 1 Controls at which frequency the displacement shader is run on the geometry before intersecting it with rays Larger values will be faster and use less memory while smaller values will yield more accurate results trace float inflategrids 0 This setting allows the grids used to trace displacements to be slightly inflated to hide cracks which may occur between them Values between 0 and 1 will usually hide most problems Turning this on can have a significant effect on performance so use it only when needed displacement int concatenate 0 When this is set to 1 and a displacement shader is instantiated its effect will be concatenated to that of existing displacement shader s in the current attribute state Any number of shaders can be linked toget
57. Prints 3Delight s version number and name h Prints a short help screen Return values The renderd1 executable can return one of the following values 0 No error 1 Bad combination of parameters An error message will explain why 99 Option licensing waitforlicense 0 was used and no license was available 255 The RIB file specified on the command line could not be read The renderdl File When started renderdl immediately looks for an initialization file named renderdl This file is a normal RIB which may contain any standard RIB command enabling the user to specifiy whatever default options are needed for rendering such as variable declarations standard screen format performance options etc The locations in which 3Delight looks for this file are in order 1 The directory of the first RIB file passed on the command line Chapter 3 Using 3Delight 11 2 The current working directory 3 The user s home directory 4 The directory pointed to by the DELIGHT environment variable Only the first renderdl file found is loaded Loading renderdl may be bypassed using the noinit option see renderdl options page 8 3 2 Using the Shader Compiler shaderdl 3Delight shaders are written in RenderMan Shading Language SL 3Delight also supports most of the common extensions to this language The shader compiler produces either an object code shader a DSO on IRIX and Linux a DLL on Windows or a byte code shader
58. REPRS 153 level of detail and procedurals 154 level of detail quality 000 154 level of detail reference camera 52 licensing options eee 42 licensing multiprocessing ssurrrrrer 122 licensing mualtu tbreading 122 light cache control illuminance 76 light categorie 74 light categories seriti res ereke ninn aai ee eee 161 lghtcache gie ZE EE 76 lighting fUnChiONS verra SEENEN en 94 linear space texture mapping 140 load balancing multiprocessing 120 LOD EE 153 logarithmic color encoding ssesrerua 173 lookuptype photonmap shadeop 106 loops e EEN 73 loops while seller c t emergere d rre pg T3 M MacOS X installing on 4 maxdepth RiOntion eee 38 maxdiffusedepth attribute 00 46 maxdiffusedepth for photons 5 fi maxdist occlusion parameters 102 maxerror BiAttrcibute i ricrccscricressrer 47 maxspeculardepth attribute 46 maxspeculardepth for photons 37 maxvpdepth hider 0 cece eee eee 33 meanfreepath Bikttribute ss 48 membership attributes sslssssessss 44 message passing xci scie cese ve gus d 75 message passing and information 113 message passing backward ssusrrrrur 75 message passing forward 75 messages options
59. Returns x resolution y resolution aspect ratio FrameAspectRatio uniform float Frame aspect ratio Hider uniform string Current hider CropWindow uniform float 4 Crop window coordinates as specified by RiCropWindow DepthOfField uniform float 3 Returns fstop focal length focal distance as specified by RiDepthOfField Shutter uniform float 2 Returns shutter open shutter close as spec ified by RiShutter Clipping uniform float 2 Returns near far as specified by RiClipping Ri FrameBegin uniform float Returns the frame number given to RiFrameBegin limits gridsize uniform float Option limits gridsize limits texturememory uniform float Option limits texturememory trace maxdepth uniform float Option trace maxdepth trace specularthreshold uniform float Option trace specularthreshold searchpath shader uniform string shader searchpath searchpath texture uniform string texture searchpath searchpath display uniform string display searchpath searchpath resource uniform string resource searchpath searchpath archive uniform string archive searchpath searchpath procedural uniform string procedural searchpath shutter offset uniform float Option shutter offset user useroption any type A user defined option Table 6 21 optionO field names Chapter 6 The Shading Language 117 Name Type Description renderer uniform string Returns 3Delight
60. Ri Filter Plug ins page 212 Initialization Each DSO provides a RifPluginManufacture entry point that creates an instance of the plug in Each such plug in derives from the RifPlugin abstract class At this stage the plug in decides which Ri commands will be filtered and what to do with Ri commands that are not processed by the plug in either continue execution of other plug ins in the chain or terminate immediately in the chain of execution Note however that a plug in can decide to run in the continue mode but Or DLL on Windows Chapter 7 Rendering Guidelines 164 switch to the terminate mode later on and vice versa As an example Listing 7 17 shows the initialization code of a very simple plug in filter that computes the total area of all spheres in some given scene include ri h include rif h include lt stdio h gt include lt string h gt include lt math h gt class Example public RifPlugin public Example 1 m filter Filtering RifFilter k Continue m filter SphereV myRiSphereV m area 0 0f b virtual Example d fprintf stdout Total RiSphere area f n m area y virtual RifFilter amp GetFilter return m filter private float m area RifFilter m filter static RtVoid myRiSphereV RtFloat radius RtFloat zmin RtFloat zmax RtFloat tmax RtInt RtToken RtPointer I RifPlugin RifPluginManufacture int argc char argv return new Example
61. SIMD execution context each shading sample can have a different importance That is why it is necessary for the output of rayinfo importance to be varying R5052 Two different displays can t write to the same file will keep display and ignore display This will happen if you are trying to write into the same file using two different display drivers For example Display test tif tiff rgb Display test tif png a R5053 channel channel is out of range for texture texturename last valid channel is maxchannel This happens when asking for a texture channel that is out of range For example if the texture has only one channel then the following code will produce an error Chapter 9 Error Messages 188 uniform float channel 1 out of range for mono textures color test ptexture monochromatic ptex channel faceindex R5054 filter badfilter is unkown will default to defaultfilter A wrong fitler name was specified to a texturing function such as texture or ptexture R5055 please use ptexture shadeop to open ptexture files ptexture is ptexturename When working with ptextures one has to use the ptexture shadeop R5056 invalid volume intersection strategy strategy valid tokens are additive and exclusive R5057 invalid number of parameters for distribution distribution The named distribution given to trace needs a specific number of parameters For example
62. Section 5 1 options page 29 Multi platform Support with Specific Code Optimization 3Delight is available for Windows Linux MacOS X and IRIX Chapter 2 Installation 4 2 Installation 2 1 MacOS X An auto install package is provided for MacOS X users Administrator privileges are needed to install 3Delight because everything is copied to Applications Graphics 3Delight 3 0 0 which is not accessible to all users The installation program asks for the appropriate password The installer adds a few lines to the etc csh cshrc etc csh login and etc bashrc files The original files are saved as etc csh cshrc 3delight bck etc csh login 3delight bck and etc bashrc 3delight bck respectively To test your installation perform the following easy steps 1 Open a Terminal and type the following commands cd DELIGHT examples rtshadows renderdl shadtest rib 2 A file named shadtest tif should appear in the current directory You can view it with any image viewer Other examples are available in the examples folder We suggest you run them If you encounter problems during installation write to info 3delight com and we will be glad to provide assitance 2 2 UNIX For UNIX systems IRIX Linux an installation script is provided It should do everything for you Here is an example of an installation session the 3Delight gz file has been downloaded into the downloads directory and is to be installed in the software directory
63. The Shading Language 111 Name Type coordsystem string radius varying float radiusscale float interpolate float Default world based on grid 1 0 0 0 Description Specifies the coordinate system into which the val ues are written Specifies the radius of the disk or sphere if N is 0 covered by each baked sample Allows scaling of the radius value without over riding it In point cloud files the size of a disk af fects the importance of its orientation for lookups with texture3d Larger disks are less likely to be picked if the normals do not match They are more strongly oriented When set to 1 0 saves the centers of the micro polygons instead of its corners This is primarily useful for point based occlusion and color bleeding see Section 7 7 3 Point Based Imaging Pipeline page 145 Table 6 17 bake3d optional parameters Additionally there is two channel names that are reserved for use with point based occlusion and color bleeding see Section 7 7 Point Based Occlusion and Color Bleeding page 145 float area Specifies the area of the given point It is not necessary to specify this channel if it is not different from the actual micro polygon area color _radiosity Specifies the radiosity at the given point This is used for point based color bleeding float texture3d string bakefile point P normal N This shadeop is used to perform lookups in file
64. This can also improve performance when micropolygons are much smaller than they need to be due to excessive geometric Chapter 5 Attribute Attribute Attribute Attribute Attribute Attribute Attribute 3Delight and RenderMan 53 detail in the scene However the very same situation can cause issues with texture filtering if the overpaint zone is not large enough procedural integer reentrant 1 When run with multiple threads 3Delight may choose to call the same procedural function with different data from more than one thread at once If some procedural is not thread safe this attribute can be set to 0 to disable that behavior The default should be used for better performance shade string frequency motionsegment This controls how often primitives with multi segment motion blur are shaded The default value of motionsegment shades at the start of every segment A value of frame specifies shading only once per frame at the first segment This is less accurate but will usually be faster and use less memory Note that some primitives only support motionsegment in which case the attribute is silently ignored shade volumeintersectionstrategy exclusive Dictates what to do with intersecting interior volumes By default only one of the interior volume is run If set to additive all volumes in an intersecting region will be evaluated shade integer smoothnormals O Setting this attribute to 1 te
65. This should never happens and could mean serious system overload A2062 RiProcRunProgram cannot create child process memory problems On unix systems this means the the fork system call has failed This should never happens and could mean serious system overload A2063 RiProcRunProgram system error in the child process A child process which was fork ed is unable to issue a dup2 command This should never happens and could mean serious system overload A2064 RiProcRunProgram cannot execute program On unix systems this means the the execl system call has failed The specified program may not be executable verify permissions Chapter 9 Error Messages 178 A2065 RiProcRunProgram cannot open reading stream for program program 3DELIGHT was not able to establish a reading connection with program This should never happens and could mean serious system overload A2066 RiProcRunProgram program program seems to have crashed or terminated early It should handle multiple requests one per line A2067 RiProcRunProgram cannot find program program This usually means bad search path settings A2084 cannot find archive archivename The specified archive could not be found If it is an inline archive it may have gone out of context If it is a file the search paths may be wrong A2085 cannot open archive file archivename Verify permissions C2046 RiBegin not called before RiCall This function has to
66. Truevision Inc GRAYSCALE GRAYSCALE ALPHA RGB RGBA INDEXED and INDEXED ALPHA formats are supported bake files These files are generated by the bake see bake shadeop page 110 shadeop and are converted to a floating point mipmapped TIFF file Output resolution can be specified using the bakeres option JPEG 8 bit grayscale and 24 bit JPEGs are supported Radiance Picture Format Files produced by Radiance are supported Both XYZE and RGBE encoding modes are recognized by tdlmake Run length encoded files are also supported Note that there is a restriction on image orientation only Y X orientation is correctly recognized any other orientation is reverted to Y X This is not a major problem since it can be corrected by using flips and flipt options see tdlmake options page 15 OpenEXR ILM s OpenEXR format is supported by tdlmake with the restriction that images should be in RGB or RGBA format zfile zfiles are only used to produce shadow maps For cube environment maps envcube all six images are required to be of the same file format 8 Refer to http floyd lbl gov radiance H Refer to http www openexr org Chapter 3 Using 3Delight 20 Quality and Performance As with all 3Delight tools tdlmake was designed to fulfill the tough demands of a production environment In this case special attention was given to filtering quality and memory usage without penalizing execution speed Among other th
67. also visible in shadow maps If an object is marked as a matte it will only cause depth to be set to infinity if it meets this threshold Option limits integer volumegroupsize 256 Controls how many points are shaded together for interior shaders and atmosphere shaders if the standardatmosphere option is set to 0 There should not be any need to change this except for debugging shaders Option shadow integer sample 16 Specifies the default oversampling value for shadow map and deep shadow map lookups This only applies if the shadow call does not contain an oversampling value see Section 6 4 6 texture mapping shadeops page 107 This option does not affect ray traced shadows Option trace integer maxdepth 2 This option sets the maximum recursion level for the ray tracer Valid values are between 0 and 32 inclusively Any value outside of this range is interpreted as 32 and a value of 0 turns off ray tracing The default value is 2 ption trace float approximation This option sets a relative detail threshold below which ray intersections may be approx imated The number specifies the ratio between the area of the intersected primitive and the arrea of the ray at the intersection point If the ratio is smaller or equal to the specified value the intersection is performed on approximate geometry The default value of 4 is a safe compromise between quality and speed meaning that an object which is only 4 times larg
68. any number of input parameters This defines an attribute category for the grid 1 The plug in itself uses the Sx API to query this shader Chapter 10 Developer s Corner 242 The size of the output array determines the number of attributes in the category This parameter can be specified up to 3 times with different shader names in order to create multiple attribute categories In addition to this parameters that need to be passed to the grid s shaders can also be specified through additional name value pairs uniform string paramName Name of the shader parameter prefixed with the shader name as specified for the grid shader grid parameter and the parameter For example to speci fiy the parameter pointCloudFile of a shader named density paramName would be density pointCloudFile uniform type param Value Value of the shader parameter This function returns a uniform float which indicates the total number of attributes the grid will handle float VolumeTracer_GetParameters uniform string gridName Retrieves some parameters of a previously created grid The first parameter of this function gridName is the name of a grid previously created with VolumeTracer_InitGrid The following parameters are an optional list of name value pairs each pair is composed of the name of a grid parameter to be retrieved followed by a uniform variable of the appropriate type where the grid parameter s value is to b
69. are as follows Hider hidden raytrace integer jitter 1 integer samplemotion 1 float aperture 4 nsides angle roundness density integer extrememotiondof 0 string depthfilter min int maxvpdepth 1 float midpointratio 0 5 int progressive 0 float samplelock 1 A description for each hider parameter follows note that some of the parameters apply only to one particular hider Hider hidden raytrace jitter 1 Selects the sampling pattern to use 0 uses a regular sampling grid and 1 uses a jittered grid Hider hidden raytrace samplemotion 1 Disables motion blur sampling when set to 0 Unlike setting the shutter open and close times to the same value by using RiShutter this method will preserve the dPdtime vectors for use in shaders or as output variables Chapter 5 3Delight and RenderMan 32 Hider hidden raytrace float aperture 4 nsides angle roundness density This feature can be used to specify a polygonal bokeh in both REYES and ray tracing modes nsides specifies the number of sides blades in the aperture and angle is used to specify the rotation in degrees of the aperture roundness and density are not supported yet Note that if nsides is smaller than 3 then the bokeh is round The default value for nsides is 0 which means that aperture is round Hider hidden extrememotiondof 0 The default algorithm used to sample depth of field and motion blur
70. as specified by RiFormat The optional cameraname can be used to specify any camera declared with RiCamera and will transform a point from current space to target camera raster space cameraname NDC The Normalized Device Coordinates Like raster space but x and y goes from 0 to 1 across the whole image In other words NDC x raster x Xres and NDC y raster y Yres The optional cameraname can be used to specify any camera declared with RiCamera and will transform a point from current space to target camera NDC space Table 6 3 Predefined Coordinate Systems Transforming point like variables between two coordinate systems is performed using the transform shadeop see transform shadeop page 92 It is important to note that that shadeop is polymorphic it acts differently for points vectors and normals The following code snippet transforms a vector from world to current space vector dir transform world current vector 0 1 0 The following exampl transforsm a point from current space to matte paints camera NDC space the camera has to be declared in the RIB using RiCamera point mattepaint NDC transform matte paint NDC P Chapter 6 The Shading Language 67 NOTE Delight keeps all points in the current coordinate system which happens to be camera This could sometimes lead to confusion point pi point world 0 1 0 printf p n p1 One could expect to
71. be specified for the object but is not big enough This could cut off displaced parts of the object Maybe the bounds should be enlarged R2054 primitive or parts of prim discarded during eye split Object is too close to the camera Parts of it are clipped R2075 cannot allocate size Kbytes for dynamic array 3Delight ios running out of memory R2076 cannot create file filename for baking system error syserror SDelight was unable to create a file passed to bake This can happen for many reasons and the provided system error should help with the debugging R2077 trying to access element index of array arrayname of size arraysize run time check failed line line of file shadername There was an out of bound access in the specified shader on the specified array Chapter 9 Error Messages 186 R2078 DELIGHT environment variable is not set Proper working of 3DELIGHT depends on this Please fix R2086 incomplete or invalid parameters set for subsurface scattering Detected some out of bound parameters for subsurface scattering Please refer to Section 7 4 5 Subsurface Scattering page 136 for guidelines R2093 object name displacement shader surface shader used only usedboundy of its displacement bound The displacement bound specified for the object is much larger than needed Perfor mance could be increased by reducing it R2377 automatic photonmaps enabled but no lights cast photons No light
72. bound 1 1 1 1 1 1 int newDepth unsigned x y z RiScale 1 0 3 0 1 0 3 0 1 0 3 0 for x 0 x 3 x for y 0 y lt 3 y for z 0 z lt 3 z if x Z2 y h2 2z 2 lt 2 Chapter 10 Developer s Corner 218 RiTransformBegin RiTranslate x 2 0 2 0 y 2 0 2 0 z 2 0 2 0 newDepth int malloc sizeof int newDepth depth 1 We could make the recursive call using RiProcDynamicLoad but that would be more complex and slightly less efficient RiProcedural newDepth bound Subdivide Free RiTransformEnd RtVoid DLLEXPORT Free RtPointer blinddata free blinddata ifdef __cplusplus endif This example can be compiled with the following commands Linux gcc o sponge so O3 I DELIGHT include shared sponge c Mac OS X gcc dynamiclib o sponge so 03 I DELIGHT include L DELIGHT lib sponge c 13delight IRIX CC o spongeso O3 n32 TARG isa mips4 TARG processor r10k I DELIGHT include shared sponge c Windows CL Ox LD I DELIGHT include sponge c DELIGHT lib 3Delight lib 10 2 3Delight APIs 10 2 1 The Rx API The Rx library provides access to some useful internal functions to SL DSOs writers Also it allows RiProcedural writers to query internal state of the renderer 10 2 1 1 Noise functions There are three noise functions They access respectively the internal implementations of noise pnoise and cellnoise in
73. by using the __CPUtime output variable It is possible to output an image where the luminosity represents the cost of shading by using a Display statement such as Display cputime tif tiff __CPUtime Objects which are more expensive to shade will be brighter You can use this image as a guide to which shaders might be worth simplifying 7 17 Using Ri Plug in Filters Ri plug in filters are an important extension to the RenderMan interface providing flexibility un known to non RenderMan systems and pipelines In short a Ri plug in is a component lying between the application that generates Ri calls such as a RIB reader like renderd1 and the rendering core Being in such a strategic place the plug in can alter or filter in any desirable way all Ri commands received by the renderer Chapter 7 Rendering Guidelines 163 bei 3Delight Renderer List of Ri Filters DSOs Ri Commands Stream RIB Reader or other Ri Program Ne J Figure 7 7 Ri plug in filters lie between the program that generates the Ri calls such as the RIB reader renderdl and the 3DELIGHT renderer 7 17 1 Ri Plug in Anatomy As pictured in Figure 7 7 a plug in is a DSO that is loaded prior to the scene description phase This section explains the general ideas behind the structure and execution of Ri plug ins a formal description of all functions available to plug ins can be found in Section 10 1 3
74. commonly called interpreted shader By default the compiler produces byte code shaders If you have a C compiler installed on your computer you can ask shaderdl to produce object code shaders by setting the dso command line switch The main advantage of byte code interpreted shaders is their platform independentness they can be used on IRIX MacOSX Linux or Windows computers This is not the case with object code shaders Object code shaders however can be faster than byte code shaders We suggest you produce object code for those shaders that are computationally intensive such as volume shaders To compile a shader use the command shaderdl shader sl As you may have noticed you do not have to specify an output file name to shaderdl The output file name is the name of the shader the identifier following the keyword surface displacement light or volume in the SL program followed by the suffix sd1 Some renderers shader compilers append the name of the platform at the end of object code shader s name 3Delight s shader compiler does not use this convention An object code shader always has the same name regardless of the platform for which it is compiled We recommend that you keep shaders compiled for different platforms in separate directories this of course is not necessary for interpreted shaders Command Line Options As with every compiler shaderdl understands a set of command line options that control the co
75. complete image The default value is off string compression lzw zw LZW compression default none No compression packbits Run length encoding deflate Deflate compression zip LogLuv compression perfect for high dynamic range images Expects floating point data as input A limitation of this compression scheme is that the alpha channel cannot be stored in the same TIFF directory as the image so it is written separately in a 2nd directory The white point is also stored in the TIFF when using this compression logluv string description s Specifies a description string which is stored in the TIFF string extratags on By default this display driver writes some useful informations to the TIFF by using the tagging mechanism however some tags are not supported by all TIFF software See table below this option can turn those tags to off Tags marked with an can be disabled using this option Visit http positron cs berkeley edu gwlarson pixformat tiffluv html for more informations about this encoding scheme 3 For a detailed specification of the TIFF format refer to http www libtiff org Chapter 8 Display Drivers 170 Tag name Description SOFTWARE Is set to something like 3Delight 0 9 6 Sep 26 2002 Fidelio IMAGEDESCRIPTION Is set to a user provided description if any XPOSITION The x cropping position in pixels only active when crop ping and fulli
76. cte eei bere ehe 33 referencecamera dice attribute s eueua 52 reflectance photon eee eee ee eee Ar reflectance BiAttribute 48 reflections ray tracing 0 00 125 refractions ray tracing 005 125 relativeshadingrate attribute 53 renderdil eie b E Mosse a MEX PPP PODER 7 renderdl rif option 10 renderdl error codes 0 cece ee eens 10 rendering RIB Dies if rendering shadow maps 122 rendering shadows eee ee 122 rendering option 34 rendermmn lhl cec nevebbes DUNG YURRPY ibis aari 59 resetrelativeshadingrate attribute 53 resizing AITAYS ee me ASSEN Babes 70 return values from renderdl 10 EEN 65 HiArchtvefegn 00 0 ec eee ee eee eee 59 RiArchiveEnd seen 59 RiArchiveRecord sseseeeeeeeee 59 RIB files rendering o vd KE NN inset dE Ne 7 rib OULD UE EE 156 RIB output options 0 0 eee eee ee eee 42 RIB output using lib3Delight 214 ribdepends oseree esee I mee IER 24 EE 56 ele EE 24 RICONE EE 57 RA CURVES d EEN NEE Ee P RH ai 55 E EE EE 57 RiDelayedReadArchive ee 57 D KEE 57 RiDisplay extensions to 29 RiDynamicLoad 66 cece ences 57 rif command line option renderdl 10 Tif RIB parsing i ecce mr nme 214 BiGeneralPolvgon ccc cece eee 55 RiHypetbolOid i 21 RI eme 0 bx 57 RiNu Patch eise hold eese e RUP A 55 Ri bgje
77. difference between multiprocessing and multithreading mul tiprocessing is implemented in the renderdl executable while multithreading is implemented in the 3Delight library While this doesn t make any difference for users that render RIBs using the renderdl command users that link with the 3Delight library can only use multithreading 7 1 5 Licensing Behavior In the multithreading case the behavior is as follows e If enough licenses are available the render will proceed normally e If there are fewer licenses available than requested threads 3Delight will start the render with as many threads as possible and will dynamically add threads as more licenses are made available e Ifthere are no licenses available 3Delight will wait for at least one license and will automatically start the render Threads will be added dynamically as more licenses are available In the multiprocessing case each launched process waits for a license to be available 7 2 Shadows 3Delight has an extensive support of shadow rendering methods It is up to you to choose the algorithm that suits you best 7 2 1 Raytraced Shadows Tracing shadow rays is an easy way for rendering shadows that requires very little setup This technique has the advantage of being convenient and efficient in the case of complex scenes Ray traced shadows are further described in Section 7 3 2 Ray Traced Shadows page 126 7 2 2 Standard Shadow Maps These are normal shadow m
78. diffuse subsurface or transmission label uniform string Returns the label attached to this ray if any Table 6 23 rayinfo field names float raylevel float isindirectray float isshadowray Deprecated functions Their functionalities can be reproduced using the rayinfo shadeop See rayinfo shadeop page 117 float arraylength var Returns the number of elements in the array var or 1 if var is a scalar float isoutput var Returns 1 if var is output to a display driver This is true if Chapter 6 The Shading Language 118 1 The variable is declared as output in shaders parameters 2 The variable is specified in at least one display driver This function is useful to optimize shaders that have to calculate many AOVs it is wasteful to compute an AOV if there is no display driver that uses it surface shader1 output varying float noisy 0 if isoutput noisy noisy noise P float isoutput string varname Returns 1 if the variable with the given name is output to a display driver This is the same function as the other form above but by name instead of directly giving the variable to test This form can also query individual array components surface shader1 output varying float outputs 3 if isoutput outputs 1 1 outputs 1 foo void outputchannel uniform string channelname value This function allows output variables
79. environment shadeops meaning that textures that are never accessed do not waste cache space Delayed Archives Cached only if occlusion culling determines that the archive is visible meaning that invisible models do not waste cache space Archives Cached immediately The design of the network cache was justified by the following observations e Rendering a sequence on a render farm puts a great amount of pressure on the network and file server s starting a heavy job simultaneously on many machines can make the network unusable and the file server non responsive especially on slow networks or weakly configured environment e Accessing a file locally is faster than accessing it on a network mounted system such as NFS Clearly texture and archive access can have a significant impact on rendering speed e File server s load would be greatly minimized since file access requests happen less often e The nature of the rendering process makes it very probable that a texture or archive used during a rendering of a given image is used again in forthcoming renderings of more images so keeping it handy is a good investment e Storage is cheaper and simpler than bandwidth Activating the Network Cache To enable the network cache use the following RiO0ption Option netcache string cachedir tmp 3delight_cache This informs 3Delight to use a directory named tmp 3delight_cache to cache textures files If the dire
80. example Formats a float using the style d ddde dd that is exponential notation This is the recommended conversion for floats when precision matters The floating point is converted to style 4f or 4e If a precision specifier is used f is applied Otherwise the format which uses the least characters to represent the number is used Equivalent to 0f useful to format integers Formats a point like type point vector normal using the style Dr 4f 4f Same as Ap but for colors Formats a matrix using the style Vf LEE Af Af HE AL HE Af Af Af Af f Af 4f 4f if a precision specifier is used Otherwise each element is formatted to full precision as with 4g Formats a string Formats a shader handle Light shaders and co shaders will use the handle of their declaration The null shader object is output as null Surface Dis placement etc become surface displacement etc Note that all conversion characters recognize the precision specifier EXAMPLE Chapter 6 The Shading Language 113 Formats a float using exponential notation string expo format Ae sqrt 27 Formats a float with 5 decimals in the fractional part point p sqrt 5 string precisionb format p 5p p Aligns text string aligned format 420s align me please void printf string pattern vali valn Same as format but prints the formatted string to stdout instead of retur
81. field of view for fov option h for help The fov option requires one scalar value as decribed in tdlmake options page 15 T0430 missing wrapping mode for smode tmode or mode option h for help T0450 optionname option is not useful for this texture type The option specified by optionname is not used for the asked conversion For example specifying the fov option to a simple texture conversion is useless since fov is only valid for environment maps More about tdlmake options in tdlmake options page 15 T0451 output is the same as input Overwriting the input file is not permitted T0455 tdlmake warning reading texture texturename may take a large tdlmake amount of memory Please refer to user s manual if you are tdlmake unable to convert this file See Working with Large Textures page 20 T0456 tdlmake error reading previous mipmap level tdlmake accesses the destination texture in both writing and reading when building mip map levels and this error indicates the mixing of those two operations did not succeed We encountered such errors when textures are being created on SAMBA drives WINDOWS platforms The problem can be fixed by updating to a newer SAMBA device driver or creating the texture on a local drive T0459 tdlmake cannot read file texture system error systemerror tdlmake is unable to read the file T0460 tdlmake invalid zfile filename T0461 mi
82. float step float min value float smoothstep float min max value step returns 0 if value is less than min otherwise it returns 1 smoothstep returns 0 if value is less than min 1 if value is greater than or equal to max and returns a Hermite interpolation between 0 and 1 when value is in the range min max A very large floating point number is actually returned it is equal to FLT MAX approximately 3 4e38 Chapter 6 The Shading Language 91 type mix type x y alpha Returns x 1 alpha y alpha For multi component types color point the operation is performed for each component float filterstep float edge value float filterstep float edge value1 valued type type type type type 6 4 2 type type type type type type type type type type type type type Similar to step but the return value is filtered over the area of the micropolygon being shaded Useful for shader anti aliasing Filtering kernel is selected using the filter optional parameter Recognized filters are gaussian box triangle and catmull rom Default is catmull rom If two values are provided return value is filtered in the range valuel value 2 spline string basis float value type begin p1 pn end spline string basis float value type p Interpolates a point on a curve defined by begin p1 to pn and end control points value s
83. float t 1 2 3 WARNING create a static array of size 3 Resizing Arrays Resizable arrays can be resized using the resize shadeop as in float A resize A 3 Note that the three elements of A in the example above are not initialized Arrays can also be resized by assignment float A float B resize A 3 4 Tf less initializer are specified the remaining elements are set to zero Chapter 6 The Shading Language 71 B A B is now of length 3 Arrays can be resized by adding or removing elements from their tail float A push A 1 push A 2 length 2 pop A length 1 resize push and pop are further described in Section 6 4 10 Operations on Arrays page 119 Array s Capacity Additionally to its length a dynamic array has a capacity Declaring a capacity for a dynamic array is solely a performance operation it allows a more efficient memory allocation strategy capacity is described in Section 6 4 10 Operations on Arrays page 119 6 1 5 Variable Classes Additionally to variable types the RenderMan shading language defines variables classes Since the beginning RSL shaders were meant to run on a multitude of shading samples at a time a technique commonly called single instruction multiple data or in short SIMD SIMD execution was a natural specification for the shading language mainly because the first production oriented RenderMan co
84. from the C binding using RiProcedural are supported Built in procedures for the RIB binding RiProcDelayedReadArchive RiProcRunProgram and RiProcDynamicLoad are also fully supported The following two RIB bindings were added to provide functionality equivalent to calling RiProcRunProgram or RiProcDynamicLoad directly from a C program ProcDynamicLoad dsoname dsodata detail ProcRunProgram progname progdata detail They invoke the corresponding procedural immediately when encountered in a RIB Unlike their counterparts used through the Procedural RIB binding they can be used to alter the current at tribute and transform stacks Note that the corresponding binding for RiProcDelayedReadArchive is simply ReadArchive 3Delight also supports a RiProceduralV C API which allows the following parameters to be specified string instancekey Setting this makes 3Delight handle procedurals for which it has the same value as instances of the same geometry This means the procedural may be expanded only once and its output reused internally This can improve both performance and memory use Limitations Procedural primitives cannot be used inside a RiMotionBegin RiMotionEnd block They can still be subject to transformation motion blur as well as contain motion blocks themselves When a procedural primitive contains a motion block it is the user s responsability to take it into account when providing the renderer with a bounding box fo
85. from top to bottom left to right spiral Rendered in a clockwise spiral starting at the center of the image circle Rendered in concentric circles starting at the center of the image random Rendered in no particular order Should not be used since it is not memory efficient Option render integer standardatmosphere 1 Traditionnally volume shaders are applied on top of surface shaders on a per surface basis While this approach is fine for basic effects like the depthcue shader it is very limiting for more complex volumetric effects which make use of ray marching It suffers from a well known issue with transparent surfaces parts of the volume are integrated several times leading to undesirable artifacts It also becomes very slow as the geometric complexity of the scene increases Chapter 5 3Delight and RenderMan 35 This option when set to 0 allows the use of an alternate algorithm better suited for volumetric effects It handles transparent surfaces properly and provides better performance characteristics with complex scenes However it requires that volume shaders follow a few rules for proper composition 1 The volume shader must be built so that it can be evaluated independently of the surface and later composited Volume shaders are normally given the color and opacity of the surface as input but with this option they will receive only black Thus they must do their work without surface values v
86. gaussian filter Note that the filename in argv 1 is a pointer of a string extern C SHADEOP rxTexture RtString filter gaussian return RxTexture RtString argv 1 0 3 RtFloat argv 2 RtFloat argv 3 RtFloat argv 4 RtFloat argv 5 RtFloat argv 6 RtFloat argv 7 RtFloat si argv 8 RtFloat argv 9 RtFloat argv 0 width RtFloat argv 10 filter amp filter 0 The DSO has to be compiled with the shared flag activated as shown below for each platform Linux g shared o rxexample so I DELIGHT include rxexample cpp IRIX CC shared o rxexample so I DELIGHT include rxexample cpp MacOS X g dynamiclib o rxexample so I DELIGHT include rxexample cpp Windows cl I DELIGHT include DELIGHT lib 3delight lib LD rxexample cpp 10 2 2 The Gx API This API allows the evaluation of RenderMan geometry The design principal is to provide the user with an interface that is easy to use and coherent with the rest of the RenderMan protocol All geometry types that are supported by 3Delight can be evaluated using this API this includes subdivision surfaces including hierarchical subdivision surfaces polygons NURBS conics Etc To use the interface one must include the gx h header file 10 2 2 1 Entry Points GxGeometryHandle GxGetGeometry RtObjectHandle i_object GxGeometryHandle GxGetGeometryV RtObjectHandle i object Rt
87. given solid angle solar vector axis float angle statement For the same reason as in the case above 3Delight doesn t consider the angle variable and considers this form as solar vector axis O statement An example directional light is listed in Listing 6 3 This light source cast lights towards the positive z direction and has to be properly placed using scene description commands to light in any desired direction light directionallight float intensity 1 color lightcolor 1 1 solar vector shader 0 0 1 0 Cl intensity lightcolor Y Listing 6 3 An example directional light using solar 9 And some sampling for custom made illuminance loops Chapter 6 The Shading Language 78 The gather Construct This construct explicitly relies on ray tracing to collect illumination and other data from the surrounding scene elements In other words this construct collects surrounding illumination through sampling Incidentally gather is well suited to integrate arbitrary reflectance models over incoming indirect light light that is reflected from other surfaces The general form of a gather loop is as follow gather string category point P dir angle samples statement else statement The lt P dir angle gt triplet specifies the sampling cone and samples specifies the number of samples to use more samples will give more accurate results The angle should be specified in rad
88. h header file and is further investigated in the following sections 10 1 1 1 Required Entry Points A display driver must implement four mandatory entry points PtDspyError DspyImageQuery PtDspylmageHandle image PtDspyQueryType type int size void data Queries the display driver about format information PtDspyError DspyImageOpen PtDspyImageHandle image const char drivername const char filename int width int height int paramcount const UserParameter parameters int formatcount PtDspyDevFormat format PtFlagStuff flags Opens a display driver PtDspyError DspyImageData PtDspyImageHandle image int xmin int xmax plus one int ymin int ymax plus one int entrysize const unsigned char data Sends data to display driver PtDspyError DspyImageClose PtDspylmageHandle image Closes the display driver An optional entry point is also defined PtDspyError DspyImageDelayClose PtDspyImageHandle image Closes the display driver in a separate process This means that renderer will exit leaving the display driver running This is particularly useful for framebuffer like display drivert Every function is detailed in the following sections DspyImageQuery This function is called for two reasons 1 3Delight needs to know the default resolution of the display driver This may happen if the user did not call Format 2 3Delight needs to know whether the display driver overwrites or not the specified file not
89. have nice properties such as filtering and automatic level of detail There is two ways to convert a point cloud file into such a texture a By using the ptc2brick utility see Section 3 9 Using ptc2brick page 26 as in ptc2brick scene ptc scene bkm b By calling RiMakeBrickMap from inside a RIB file or programmatically from inside a C source file MakeBrickMap scene ptc scene bkm NOTE The first parameter to RiMakeBrickMap in the example above is an array of strings and not a single string This means that the command can receive more than one point cloud file at a time The same applies to ptc2brick more than one point cloud file can be specified as input A brickmap file can then be accessed using the texture3d shadeop see texture3d shadeop page 111 exactly as for point cloud files 7 6 4 Baking Using Lights One potential downside to baking is the necessary modifications to all contributing shaders The basic structure of a shader that has been modifying for baking is similar to this surface foo common parameters baking related parameters Main shader s code baking code The most annoying part of this approach is the addition of the baking related parameters Not only one has to add them to all shaders but also one needs to specify them for each shader instance One solution to this problem is to specify the baking parameters as user attributes Attribute user string bakef
90. hider the renderer will not render the scene but instead store all the computed photon maps into files specified by Attribute photon globalmap and Attribute photon causticmap Those photon maps can then be read by specifying the same attributes in a normal render using the hidden hider An example of this approch is found in the DELIGHT examples photons directory Chapter 7 Rendering Guidelines 133 The total number of bounces a photon can travel can be specified on a per prmitive basis for example Attribute trace maxdiffusedepth 10 maxspeculardepth 5 7 4 3 Final Gathering Final gathering is a technique to render global illumination effects color bleeding efficiently In summary for global illumination rendering using n bounces the algorithm first proceeds by emitting photons from light sources for the n 1 bounces Then the last bounce is simulated by tracing a specified number of rays from surfaces at each ray surface intersection the photon map is used to compute the radiance The main benefit here is that instead of ray tracing the entire n bounces we only ray trace one bounce and the rest is available through photon maps This functionality is readily available using the indirectdiffuse shadeop see indirectdiffuse shadeop page 99 which traces a specified number of rays in the scene and collects incoming light If indirectdiffuse encounters photon maps on surfaces it will automatically use them a
91. how to call the error message handler error_handler RIE CONSISTENCY RIE ERROR dspy z need z in order to proceed n return PkDspyErrorUnsupported h if nl np 1 error handler RIE CONSISTENCY RIE ERROR dspy z need Nl amp Np matrices in order to proceed bug n return PkDspyErrorBadParams if i_width gt USHRT_MAX i_height gt USHRT_MAX error_handler RIE_LIMIT RIE_ERROR dspy z image too large for zfile format use shadowmap display driver n return PkDspyErrorUndef ined zFile aZFile new zFile i_filename np nl i_width i_height if aZFile aZFile ValidO 1 error handler RIE SYSTEM RIE ERROR dspy_z cannot create file n 1 delete aZFile return PkDspyErrorNoResource Chapter 10 Developer s Corner i_phImage void aZFile Ask display manager to provide data scanline by scanline flagstuff gt flags PkDspyFlagsWantsScanLineOrder return PkDspyErrorNone DspyImageQuery PtDspyError DspyImageQuery PtDspyImageHandle i_hImage PtDspyQueryType i_type int i_datalen void i_data zFile aZFile zFile i_hImage if i data 1 return PkDspyErrorBadParams size_t datalen i_datalen switch i_type case PkSizeQuery PtDspySizeInfo sizeQ if aZFile sizeQ width aZFile gt GetWidth sizeQ height aZFile gt GetHeight sizeQ aspectRa
92. in a separate process so that 3Delight can exit without waiting for the display driver The framebuffer display driver uses this functionality see Section 8 2 This is better than using printf or the like Chapter 10 Developer s Corner 198 framebuffer page 168 This is not supported on Windows so it should be avoided whenever possible 10 1 1 2 Utility Functions IMPORTANT The following functions are useful to search through the parameters list and to per form some other low level tasks Note that there is a slightly annoying side effect it becomes mandatory to link with 3delight dll on the Windows operating system see Section 10 3 link ing with 3delight page 244 This means that display drivers that use these functions are not directly usable with other RenderMan compliant renderers and will have to be re compiled for them although with no other modfications PtDspyError DspyFindStringInParamList const char name char result int parameters_count const UserParameter parameters PtDspyError DspyFindFloatInParamList const char name float result int parameters_count const UserParameter parameters PtDspyError DspyFindFloatsInParamList const char name int result_count float result int parameters_count const UserParameter parameters PtDspyError DspyFindIntInParamList const char name float result int parameters_count const UserParameter parameters PtDspyError DspyFindIntsInPara
93. included All used archives executables must be present in default search paths It is possible to cause procedurals to be turned into archives read with DelayedReadArchive by using the rib callprocedurals option see RIB Output Options page 42 10 librib a or libribout a Chapter 7 Rendering Guidelines 158 Set output format to binary int fd open test rib O_WRONLY RiOption rib pipe amp fd RI NULL Set output format to binary Can also be done inside the Begin End block RtString format 1i binary RiOption rib format RtPointer format RI NULL Enable procedurals expansion during output Can also be done inside the Begin End block RtString expansion 1 on RiOption rib callprocedurals RtPointer expansion RI NULL RiBegin RI NULL Scene description follows here RiEnd close fd don t forget to close that file gt Listing 7 14 RIB output using pipes renderdl can also be used to redirect the RIB stream to a file by using the catrib option see renderdl options page 8 Redirecting a RIB into another RIB may sound useless but is in fact useful in many regards e renderdl can output binary encoded RIBs using binary which are much smaller in size than their ascii counterpart e renderdl can read binary RIBs so it can be used to convert those into a humanly readable ASCII format e It is sometimes desira
94. ins All Rif API function and class definitions are defined in DELIGHT include rif h so this file must be included API entry points are described in the following sections Plug in Entry Points The following functions should be defined in all Ri plug in filters RifPlugin RifPluginManufacture int argc char argv This function is called after the plug in is loaded It should return an instance of the Ri plug in filter An example is provided in Listing 7 17 All parameters are passed us ing i argc and i Argv as for the mainO in C The RiPlugin abstract class is defined in DELIGHT include rif h and all plug in filters must derive from it Chapter 10 Developer s Corner 213 class RifPlugin 1 public virtual RifPlugin O virtual RifFilter amp GetFilter 0 3 The RifFilter structure returned by RifPlugin GetFilter contains all the filtering information refer to Section 7 17 Using Ri Plug in Filters page 162 for usage examples struct RifFilter 1 enum k UnknownVersion 0 k CurrentVersion 1 enum k Continue 1 k Terminate 2 DefaultFiltering int Filtering short Version void ClientData char Reserved 64 RifFilter Transforms RtVoid Perspective RtFloat fov RtVoid ConcatTransform RtMatrix transform RtVoid CoordinateSystem RtToken space RtVoid ScopedCoordinateSystem RtToken space RtVoid CoordSysTransform RtToken space RtVoid Ident
95. into this layer in the chain k RifParseFirstLayer Inject RIB stream into first layer in the chain The declaration of RifParseMode is found in DELIGHT include rif h typedef enum 1 k RifParseNextLayer k RifParseThisLayer k RifParseFirstlayer RifParseMode RtVoid RifParseBuffer const char i buf unsigned i size RifParseMode i mode Same as RifParseFile but parse RIB commands from memory 10 1 4 Procedural Geometry Plug ins This section is meant to provide examples on how to write simple procedural primitives for 3Delight For more complete documentation about procedural primitives and the interface to them refer to the RenderMan Interface Specification 10 1 4 1 The RunProgram Procedural Primitive This example shows how to write a procedural primitive in the form of an external program which generates RIB It can be invoked in a RIB stream as such Procedural RunProgram sphere O O 5 1 1 1 1 1 1 1 The three floats it receives as parameters represent a color as expected by the program The program itself outputs a sphere of that color This example also shows how to generate a RIB using Chapter 10 Developer s Corner 215 lib3delight Note that on Windows 3Delight searches for sphere exe if it doesn t find sphere in its procedural search path Note that a poorly written program especially one which fails to output the 377 delimiter may easily hang the renderer Great care was taken in 3Deligh
96. is not recommended and will create large and inefficient brick maps newer Only builds the brick map if one of the input files is newer than the output This option has no effect if the output file doesn t exist h Prints a help screen A brick map is a 3D texture file format that is suitable for anti aliased lookups Please refer to Section 7 6 Baking page 141 bake3d shadeop page 110 and texture3d shadeop page 111 for further discussions 3 10 Using ptcview ptcview displays a point cloud file in a window The generl command line syntax is ptcview info h file ptc When started with an empty command line ptcview will start with an empty window A point cloud can then be loaded through the File menu item When provided with a file this utility will proceed with the load prior to display Here is the list of supported functionalities 1 All channels contained in the point cloud can be displayed through the View Channels menu item 2 Point normals can be displayed through the View gt Normals menu item 3 The current view port can be copied into the clipboard as a 2D image through the Edit gt Copy menu item When given the info option ptcview will only print useful information about the given point cloud file An example output looks like this 1 Does not work on brick maps Chapter 3 Using 3Delight 27 Number of points 462694 Number of channels 1 Channel
97. is to use the raytype option as shown in Table 6 10 The only reason this attribute is provided is to keep compatibility with another RenderMan compliant renderer emit n Enables automatic photon map generation and specifies the total number of photons to cast in the scene In this mode the photon maps are not saved to disk by default More about this option in Section 7 4 2 2 Single Pass Photon Mapping page 132 Option photon Chapter 5 3Delight and RenderMan 37 Option photon writemaps n If automatic photon map is generated photon maps can still be written to disk if this option is set to 1 Default is 0 Option photon maxdiffusedepth 10 Option photon maxspeculardepth 10 Specifies the maximum diffuse and specular bounces for photons when using the au tomatic photon map approach In the two pass approach see Section 7 4 2 3 Two Pass Photon Mapping page 132 the renderer will honour the maximums specified by maxdiffusedepth and maxspeculardepth trace attributes Quality vs Performance Options Option limits integer bucketsize 2 16 16 This option specifies the dimension of a bucket in pixels Using smaller buckets may reduce memory use at the expense of slight performance loss In our experience this default value is the best compromise for 3Delight Option limits integer gridsize 256 During the rendering process geometry is split into small grids of micropolyg
98. load RtxPlugin plugin systemerror 3DELIGHT is unable to load the DSO that contains the plugin 2107 cannot find func function in RtxPlugin plugin may be missing extern C After loading the DSO 3DELIGHT is unable to get the required function 82383 not enough parameters for format string The format string given to a function such as printf or format required more arguments than were given Chapter 9 Error Messages 190 2384 parameter type does not match format string got type but expected expectedtype The format string given to a function such as printf or format requires that the following arguments be of a certain type The actual arguments did not match the requirement T0400 optionname option is not useful for algoname algorithm The option specified by optionname is not used for the asked algoname algorithm For example specifying the nscales option to the simple algorithm is useless since nscales is only valid for local tone mapping More about hdri2tif options in Section 3 5 Using hdri2tif page 22 T0425 missing space time coordinates for skymap option h for help Parameter set passed to the skymap option is incomplete please refer to Section 3 3 Using the texture optimizer page 15 T0426 invalid space time coordinates coordinate for skymap option Parameter set passed to the skymap option is invalid please refer to tdlmake options page 15 T0427 missing
99. maximum number of strings that can be written to o names It can be useful to set this parameter to O when only the number of predefined parameters and not their names is needed const char SxGetParameterInfo SxShader i shader unsigned i index Sx Type o type bool o varying SxData o defValues unsigned o arraySize const char o_spaceName 0 bool o output 0 Returns parameter s name and all information about the parameter which matches the spec ified index for the specified shader i shader The shader of interest iindex Specified index o type Parameter s type would be one of SxFloat SxPoint SxColor SxString SxMa trix SxVector or SxNormal o varying Parameter s class would be true for varying false for uniform o defValues Parameter s default values o_arraySize Parameter s array size Would be 0 if not an array o_spaceName Parameter s space for the default value optional o_output Parameter s output state optional Would be true for output false otherwise unsigned SxGetParameter SxParameterList i paramList const char i_paramName SxData o values Returns the number of values associated with the specified output variable Chapter 10 Developer s Corner 227 i_paramList The parameter list from which to retrieve values Normally this will be a list which was passed to SxCallShader i paramName Variable s name o values Values of the predefined or output variab
100. n Sets the sharpness parameter Higher values mean sharper images Default is 8 The following options control the compression applied to the output H Erik Reinhard Mike Stark Peter Shirley and Jim Ferwerda Photographic Tone Reproduction for Digital Images ACM Transactions on Graphics 21 3 pp 267 276 July 2002 Proceedings of SIGGRAPH 2002 1 Implies frequency domain computations Chapter 3 Using 3Delight 23 lzw deflate packbits none Selects compression method to use for output TIFF 1zw is enabled by default 3 6 Using shaderinfo to Interrogate Shaders shaderinfo is a utility to interrogate shaders compiled with shaderdl It could be used as a quick way to see what parameters are needed for a particular shader or it could be used by third party software to build a graphical interface to manipulate shader parameters The general command line syntax is shaderinfo options shader1 shader2 shadern And the following list of options is accepted d Output shader s parameters in a RIB format see example below t Output shader s parameters in an easy to parse tabular format a Output shader s annotations if available source Output shader s source code if the shader was compiled with the embed source option as described in shaderdl options page 11 methods Output the name of all the methods in the shader V Output shaderinfo version h Print a help screen A sample run on the matte s
101. printf d arraylen printf n printf t t s DlGetText DlText_1725_default switch parameter gt svd_type case SLO_TYPE_COLOR Even if color has a different spacename it has been converted by evaluation printf rgb Wis break case SLO_TYPE_POINT case SLO_TYPE_VECTOR case SLO_TYPE_NORMAL case SLO_TYPE_MATRIX if parameter gt svd_spacename 0 char O printf s _ parameter gt svd_spacename break default break if is_array 1 printf J int num_elements is_array arraylen 1 for int k 0 k lt num_elements k x const SLO_VISSYMDEF elem Chapter 10 Developer s Corner 235 Slo_GetArrayArgElement SLO_VISSYMDEF parameter k if elem 1 printf lt error gt continue switch parameter gt svd_type case SLO_TYPE_SCALAR printf ien elem gt svd_default scalarval break case SLO_TYPE_POINT case SLO_TYPE_VECTOR case SLO_TYPE_NORMAL case SLO_TYPE_COLOR printf De g gl elem gt svd_default pointval gt xval elem gt svd_default pointval gt yval elem gt svd_default pointval gt zval OD break case SLO_TYPE_MATRIX printf Den elem gt svd_default matrixval 0 for int kk 1 kk lt 15 kk printf Ag elem gt svd_default matrixval kk J printf ein elem gt svd_default matrixval 15 break case SLO_TYPE_STRING printf s elem svd defaul
102. ptcview can be used to verify that the save point cloud file contains all the necessary points 2 Shading Rate This determines the total number of points in the point cloud This is an important quality vs speed control knob higher shading rates will lead to faster processing times and smaller point cloud files at the expense of a lower quality render 3 Resolution This has the same impact as the shading rate During the main beauty pass the important control parameters are all part of occlusion parameter list see occlusion shadeop page 99 maxdist This parameter is an important look control knob in point based occlusion As ex plained below point based occlusion is not good when rendering very dense environ ments since and this parameter artificially lowers the complexity of the scene for the algorithm maxsolidangle This is a quality vs speed control knob A good range of values is 0 01 to 0 5 clamp Setting this parameter to 1 will force 3 Delight to account for occlusion in dense envi ronments The results obtained with this parameter on should look similar to what a ray traced rendering would give Enabling this parameter will slow down the point based algorithm by a factor of 2 Chapter 7 Rendering Guidelines 148 7 8 Multi Camera Rendering 3Delight is able to render many camera views in a single run This feature is commonly called multi camera rendering and is particularly useful for stereo rendering both the
103. rate for 3Delight 3delight shadingrate 0 5 set default shader path 3delight defaultsearchpath shader HOME shaders DELIGHT shaders the file display drivers defaults to tiff displaytype file tiff set default resolution for the tiff display driver display tiff xres 800 display tiff yres 600 specify the library to use for a custom display driver display dso stereo 1ib foo stereo_dd so Listing 5 2 An example rendermn ini file Finally setting the DL_DUMP_DEFAULTS environment variable forces 3Delight to print all read keys and their values from the configuration file s Chapter 6 The Shading Language 62 6 The Shading Language 6 1 Syntax 6 1 1 General Shader Structure 6 1 1 1 Traditional Structure Traditional shaders are pre RSL 2 0 shaders they exhibit a very simple structure consisting of one main entry point and a certain number of supporting functions a structure clearly inspired by the C programming language Function declarations surface displacement volume imager light shadername Parameters Shader body The output of such shaders depends solely on their type and is passed back to the renderer through a standard output variable see Section 6 2 Predefined Shader Variables page 84 Here is a summery for each shader type surface Surface shaders define the color and the opacity or transparency of the material by setting the Ci and Oi output variables displa
104. really worth the effort to carefully optimize shaders e Use uniform variables whenever possible Remember that 3Delight s shaders run in SIMD which means that an operation processes many shading samples at once uniform variables are computed only once per grid contrary to varying variables which are computed once per micro polygon Consider the following example surface test float i_angle PI 0 5 float half_angle i_angle 0 5 more code goes here There is a hidden overhead in this shader since i angle is uniform and half angle is varying This means that half angle is initialized to the same value i_angle 2 for each micro polygon on the grid Although the shader compiler optimizes some varying variables into uniform declaring half angle as uniform guarantees to avoid unnecessary operations e Avoid using conditionals in shaders Conditionals can stall 3Delight s SIMD pipeline which has an impact on shaders execution speed e Use light categories Evaluating light sources is a non negligible part of total shading time Light categories can help avoid evaluating light source shaders which are not needed in some particular context A very good example is an atmosphere shader that uses a ray marching algorithm to compute volume s translucency and color for each sample along the marched ray illuminance is called to compute incoming light which triggers the evaluation of all attached light s
105. running on the computer named servername L2031 make sure the license server is running on servername The renderer is unable to contact the license server that has been specified in the rendermn ini file Make sure that the rendermn ini file is right and that the license server licserver is running L2032 please complete the rendermn ini file as explained in InstallationGuide pdf This means that you are running without a license and that a watermark will be displayed Completing the rendermn ini file with the 3delight licserver line will solve the problem L2033 invalid license key Server was contacted but license key is invalid It may have expired or the setup is not done properly L2034 all licenses are taken waiting for a free license delay There are not enough licenses available to proceed with the render 3DELIGHT will wait until a license is available If the preferred behavior in this case is to exit immediately please add the following line to rendermn ini 3delight waitforlicense 0 L2035 cannot resolve license server servername The computer named servername could not be found This looks like an incorrect setup in the rendermn ini file L2036 no more than numservers license servers can be specified Some special licenses allow many license servers to run for geographically separated sites for example This error message indicates that you are trying to run more license
106. servers than permitted Chapter 9 Error Messages 180 L5034 licserver can t connect to service control manager L5035 licserver service does not exist L5036 licserver can t open existing service L5037 licserver error uninstalling service L5038 licserver error installing service L5039 Manages licenses for 3Delight and related products L5040 licserver service uninstalled L5041 licserver service installed L5059 License does not support this version of product Use an older version or contact sales to renew support P1000 invalid grouping membership groupname Format is invalid There might be multiple or in the membership P1001 catmull clark subdivision mesh objectname edge between vertices vertexi and vertex2 has more than two attached faces The mesh definition is not a manifold Some faces will be ignored P1002 catmull clark subdivision mesh objectname face has the same vertex index twice A face is using the same vertex more than once Some vertices will be ignored P1003 catmull clark subdivision mesh objectname vertex ID out of range A face is using an unknown vertex It is ignored P1004 catmull clark subdivision mesh objectname face with less than 3 vertices A face has no area This error may occur with more vertices if they are duplicated P1005 catmull clark subdivision mesh objectname facevertex variables are inconsistent so discontinuities may occu
107. sets the ray tracer as the primary renderer and switches off jittering Hider raytrace int jitter 0 The ray tracer is slower than the default REYES renderer but it could prove useful in some cases e No eye split problems Primitives that are difficult to render using the standard algorithm can be rendered in the ray tracer without problems e Motion blurred mirror like objects will have good reflections This is a classical problem in REYES renderers where shading is done only once for a mirror like objects meaning that motion blurring the mirror will blur the reflection which is not the correct behavior e Can produce nicer refractions and reflections since there is one shading point per subsample and not per micro polygon The ray tracing hider produces the same quality images as the REYES hider and supports all the features you expect from a high end renderer motion blur depth of field and correct derivatives in shaders 7 4 Global Illumination 7 4 1 Ambient Occlusion Ambient occlusion also known as geometric exposure is trivially computed using the occlusion shadeop see occlusion shadeop page 99 Objects contributing to occlusion have to be tagged as visible to transmission rays using Attribute visibility transmission opaque occlusion works by tracing a specified number of rays into the scene or can be provided with a point cloud to compute occlusion using a point based approximation The rest
108. shadow maps and obtain excellent results Now the drawbacks e Self shadowing This is the most common problem encountered when using shadow maps It ap pears as dark artifacts in areas that should appear completely lit This problem can be resolved by using an appropriate shadow bias either via an option see Rendering Options page 34 or through the bias parameter when calling shadow see shadow shadeop page 109 e Nearly impossible to generate high quality area shadows Even if tweaking with shadow blur can give a nice penumbra effect it is impossible to generate a true area shadow e Expensive to generate really sharp shadows This is because high resolution shadow maps are needed which often leads to longer render times and memory disk usage e No motion blur in shadows Moving geometry still casts shadows It is wise to remove motion blur when rendering shadow maps e No colored shadows Translucent surfaces cast opaque shadows e Only objects that are in the shadow map cast shadows That is why shadow maps work so well with spot lights they light only a limited field of view Point lights are more tricky to handle need six shadow maps and distant lights are difficult to setup with shadow maps When creating shadow maps make sure that shadow casting objects are framed correctly and tightly in the camera view that is used to render the shadow map If objects are too far small in shadow map view precision prob
109. string fromspace tospace vector V vector vtransform string fromspace matrix M vector V normal ntransform string fromspace tospace normal Nr normal ntransform string fromspace matrix M normal Nr Same as transform above but specifically selects a transform on normals or vectors no polymorphism NOTE One should use transform instead since that shadeop will correctly select the appropriate transform depending on the parameter type color ctransform string fromspace tospace color src color Transforms color src color from color space fromspace to color space tospace If the optional fromspace is not specified it is assumed to be rgb 3Delight recognizes the following color spaces RGB HSV HSL YIQ and XYZ If an unknown color space is given 3Delight returns src color When converting to and from XYZ color space 3Delight considers that RGB tristimulus values conform to Rec 709 with a white point of Des Chapter 6 The Shading Language 93 float distance point Pt1 Pt2 float length vector V vector normalize vector V distance returns the distance between two points length returns the length norm of the given vector normalize divides the given vector by its length making it of unit length All three operations involve a square root float ptlined point Pt1 Pt2 Q Returns minimum distance between a point Q and a segment defined by Pt1 and Pt2
110. the blinn distribution needs one parameters which is the roughness color result trace P N samples 16 distribution blinn roughness 0 1 wo I R5058 The specified distribution distribution was invalid R5060 memory limit exceeded rendering aborted Rendering was interrupted because memory use exceeded the processmemory option R5062 The specified bsdf bsdf needs udir direction and roughnessv value For anisotropic BSDFs such as the Ashikhmin Shirley BRDF the renderer expects a vector for anisotropy direction and a second roughness value R5063 The subsurface shadeop should be specified with an irradiance channel for correct rendering and better performance when using global illumination See Table 6 13 R5064 Cannot outpout deep data including for deep shadow maps when using ray tracer in progressive or editable mode When using the raytrace hider deep image data can only be output when progressive and editable are disabled For example the following RiHider declaration will produce this error message won t output any deep image data to the display driver Hider raytrace int progressive 1 Display image exr deepexr rgba Won t work because of the above 0523 encountered invalid operand operand during the evaluation of shader shadername The shader evaluator encountered an unknown opcode This could happen when read ing corrupted or very old shad
111. the Ri client library see Section 10 3 linking with 3delight page 244 Some renderers come with a specialized library that is intended 9 Permissions mask 0775 Chapter 7 Rendering Guidelines 157 for such usage while 3Delight provides the same functionality through the library that is used for rendering in three different ways l By specifying an output file name to RiBegin specifying an empty file name as in RiBegin outputs the RIB stream to stdout This is the recommended way for exporting geometry from 3D packages It is possible to concatenate a RIB stream to an existing file by using RiBegin gt gt filename rib It is also possible to pass the RIB stream to custom filters by using a command such as RiBegin filteringscript gzip gt final rib gz By specifying a file descriptor using the Option rib pipe option By setting the RISERVER environment variable to a valid file name before rendering more precisely before the first RiBegin call This environment variable can be of great help when debugging since one can redirect the RIB stream to a file for analysis without prior code modification Binary RIB output is possible by setting the RIFORMAT environment variable to binary Compressed output is possible by setting the RICOMPRESSION environment variable to gzip Additional controls on RIB output are provided through Ri0ption One is for binary RIB output and the other is for procedura
112. the information needed The following requests are accepted npoints Number of points in the point cloud file C data type is int bbox The bounding box of the point cloud Will return an array of six floats min x min y min z max x max y and max z datasize pointdatasize The number of floats needed to store each data point C data type is int world2eye The world to eye world to camera transformation matrix Will return an array of 16 floats world2ndc The world to NDC transformation matrix Will return an array of 16 floats format The resolution of the render that generated the point cloud file Three floats will be returned x resolution y resolution and aspect ratio nvars Total number of variables attached to each point In this case result is considered to be of type int varnames pointvarnames The name of each variable In this case result is considered to be of type char vartypes pointvartypes The type of each variable In this case result is considered to be of type char A pointer to an array large enough to hold the returned informations Chapter 10 Developer s Corner 229 Returns 1 if the request is successful 0 otherwise NOTE Some point cloud files generated with older 3Delight versions may not contain the format information int PtcReadDataPoint PtcPointCloud pointcloud float point float no
113. the mipmap levels To know if directory textures are beneficial in a particular situation one should analyze texture access statistics to see if the most detailed mipmaps are accessed or not Safety Many precautions have been taken to ensure the proper operation of the network cache 1 3Delight does not access the original textures or archives in any dangerous way only reading is performed on those files 2 The cache is kept synchronized with the files it mirrors if an original texture is newer than the cached one the cache is updated 3 A file is identified by its full path files that have the same name in different directories do not collide 4 UNIX file links are resolved prior to caching this ensures that a given file is cached only once even if many links point to it 5 The network cache is multiprocess safe Even if many renders are running on the same machine the cache is kept in a consistent state one 3Delight instance does not remove a texture or archive used by another instance 6 Cache directory is created with full access permissions to user and group but only read access to other 7 If for any reason 3Delight is unable to cache a file it reverts to use the original and this is the worst case scenario 7 15 RIB Output It is sometimes desirable to redirect the RIB stream into a file instead of sending it to the renderer This is particularly useful for applications that link directly with
114. the rendermn ini file this is not necessary Chapter 5 3Delight and RenderMan 40 Option searchpath string rslpluginmap map from map to map from map to Sets a mapping table for rsl plugin names This can be used to make a shader use a different plugin than the one it was compiled with as long as it contains the required functions Default values are shown in Table 5 3 An environment variable can be set to track down searchpath related problems see Section 2 4 Environment Variables page 5 Statistics Options Statistics can prove useful when fine tuning the renderer s behavior for quality or performance reasons Option statistics integer endofframe 0 Specifies the desired statistics level The level ranges from 0 to 3 with 0 meaning no statistics at all and 3 meaning all possible statistics A level of 2 is enough for most uses Option statistics string filename By default statistics are dumped to the console more specifically to stdout this option can be used to specify an output file name instead If the file name has the html or htm extension statistics are dumped in HTML format Note If specified the file name should be on the same line as the endofframe statistic option in order to get statistics at all Option statistics int progress 0 Turning this option on forces 3Delight to output a progress status to the console Output text looks like this
115. this in Section 6 1 7 4 Functions page 82 It is recommended not to abuse the varying and uniform keywords where the default behaviour is clear this makes code more readable 6 1 6 Parameter Lists Parameters list can be declared in three different contexts shader parameters shader class param eters and function parameters Shader and shader class parameters have exactly the same form and will be described in the same section whereas function parameters has some specifics and will be described in their own section 6 1 6 1 Shader and Shader Class Parameters This kind of parameters has three particularities 1 Each parameter must have a default initializer This is to be expected since all parameters must have a valid state in case they are not specified in the RenderMan scene description through RiSurface or similar By default each parameter is uniform see Section 6 1 5 Variable Classes page 71 They can be declared as output Meaning that they can be passed to a display driver as declared by RiDisplay Follows an example of such a parameter list surface dummy float intensity 1 amplitude 0 5 output color specular 0 shader body 6 1 6 2 Function Parameters Function parameters have the same form as shader parameters but have no initializer Another notable difference is that by default parameters class is inherited from the argument For example Chapter 6 The Shading Language 73 note that
116. way of doing things makes running displacement shaders straightforward and efficient One potential problem might arise though when rendering sequences with a moving camera the renderer might tessellate the geometry slightly differently from frame to frame leading to displacement shaders to react differently between frames and this in turn may lead to pops in static geometry This usually happens in displacement shaders that have a high perturbation frequency Although this problem can be solved using lower shading rates and proper anti aliasing it is often easier to use a dicing camera A dicing camera is a camera that is declared along with the main camera and is usually static in the animation sequence so that objects are always tessellated the same way from frame to frame One can declare such a camera using the RiCamera command Display example tif tiff rgb Format 640 480 1 Projection perspective fov 60 Translate 0 0 5 TransformBegin Translate 0 0 100 Camera faraway TransformEnd WorldBegin Translate 0 1 5 0 Rotate 90 1 0 0 Attribute dice referencecamera faraway Geometry teapot WorldEnd Listing 7 12 Declaring and using a dicing camera In this example a teapot is diced using a camera named faraway that has been placed very far see dice referencecamera page 52 So rendering the image will produce a teapot with very rough tessellation A few notes e It is possible to declare multiple
117. 3Delight 10 0 User s Manual A fast high quality RenderMan compliant renderer Copyright c 2000 2011 The 3Delight Team Short Contents iid hcg ah ak oo ee bain a dee ee an eas 1 Welcome Zeechner ated eege dei Eeer wee 2 SE dee d oe DES 4 a Using gDelsHL ciedeostaa te per be oer b eu ed doe d 7 4 Integration with Third Party Software 2 244 28 5 3Delight and RenderMan i ceo ce SEENEN 29 6 The Shading L nguagg EE 62 7 Rendering Guidelines eyeccsscecacstaegscesaduns RE Re RE re 120 B Display DEIVEEBS Loos with ee eae Ee abe 168 Or ee eet eee ete EE 177 10 Developer s Cotter sacs An steeds EE E EE EE 194 11 Acknowledgements e obere secre ERR ebd 24T 12 Copyrights and Trademarks iis rr brc Rt 248 Concept Ddile esae eiei edaran o Ed bn bua A Ea iea Etre 250 Function Indek REP 257 Listof E 260 Table of Contents IUE 1 1 Welcome to 3Delighil deer ERR ER ERE 2 1 1 What Is In This Manual 2 13 jJBeatutesugn esciad pee iad Dad ret ted M ope vbt bed p ob aat 2 2 Installations echec ee teases eed He eee eee week d ate A 21 MacOS EE 4 ER D KEE 4 2 3 e et 5 2 4 Environment Variables esnsssrsrereresrereresrresrereresreres 5 a Using 3Delght EE T 3 1 Using the RIB Renderer renderdl 00 cece eee eee ees T 3 2 Using the Shader Compiler sbaderdl 0 cece eee ee jr 3 3 Using the Texture Optimizer tdlmake 0 cee eee 15 3 4 Using dsm2tif to Visualize D Ms
118. 5 environment gather category 80 environmentcolor occlusion parameters 102 environmentdir occlusion parameters 102 environmentmap occlusion parameters 102 environmentspace occlusion parameters 102 eps display driwer 172 error codes from renderdl 10 estimator photon 0 e eee eee 48 estimator photonmap shadeop 106 Gl ecu orae wins xad rr e ERE E ES 125 examples RIB output 0 20 eee 158 exr custom header attributes 174 extensions to RiDisplay sess 29 extreme motion blur with depth of field 32 eye plane splitting 0006 3T eye splits curing e RIS Wied ie end ideas 130 eyesplits RiOption 0 cece eee 37 F facevaryinginterpolateboundary subdivision S rface TAG corie isr ku et Rr bodes REE 54 facevertex variable pe 54 falloff occlusion parameters 102 falloffmode occlusion parameters 102 features 3Delight eee eee 2 file format shadow maps 171 filtering messages 41 Hes EE 162 final eatbhering 0 eee e eee eee 133 final gathering indirectdiffuse 99 for lo0p ix be nis ER bh RE a ERIS T3 formatting file names RiDisplay 30 forward message passing 008 75 framebuffer display driwer 168 framing shadow maps 123 function index sessile i ddd e repete oe ee 257 G
119. 55 O 255 0 5 Quantize diff 255 0 255 0 5 Quantize spec 255 0 255 0 5 Display output_multi_layer psd psd amb Ci diff alpha spec 8 14 The PIC display driver This display driver writes SOFTIMAGE s PIC files RGB and RGBA formats are supported in 8 bits The following parameters can be passed to this display driver uniform string compression rle none Enables or disables compression Disabled by default string fullimage on See explanation in Section 8 3 dspytiff page 169 An example call Display image pic pic rgb string compression rle Chapter 8 Display Drivers 176 8 15 The JPEG display driver This display driver output JPEG images and is able to write 1 channel gray scale and 3 channel RGB images One parameter is accepted to control the quality of the JPEG image as outlined in the example below Display image jpg jpeg rgb int quality 80 Chapter 9 Error Messages 177 9 Error Messages This is a list of most of the error messages 3Delight can produce along with a brief description of possible causes for each A2010 RiProcDynamicLoad cannot find shared object libname Specified shared object was not found This is usually a search path problem A2011 RiProcDynamicLoad libname is not a shared library system error syserror Search paths may be in incorrect order or the file is corrupted A2012 RiProcDynamicLoad ai does not contain the necessary entry points system er
120. Behavior 0c sce e eee cence entree eeees 122 1 2 IBhadoWSscstoseedveriigpx ENEE heehee EU Ee de 122 7 2 1 Raytraced Shadows ccc sce e cece eee e ence cence eee eens 122 7 2 2 Standard Shadow Mans 122 7 2 3 Deep Shadow Maps 123 7 2 4 Aggregated Shadow Maps 124 Zi Ray Lracmg ive ate ta ase e NEE Ne deer 124 7 3 1 Reflections and Bebractions nunun 125 T8 2 Ray Traced Ohadows csse 126 4 3 3 Ray Labels sois Le becbk geet bone deed Re dr eh 127 7 3 4 Trace Group Membership 000 cece eee eee eee eee 128 7 3 5 Ray Tracing Displacements 0 c cece eee eee 128 7 3 6 Oversampling and Derivatives 0 c cece eee eee ee 129 7 3 7 The Ray Tracing Hider cee eee eee eee tee eee 130 CA Global llumanation 2 x RR RE RE EE ae ER 130 7 4 1 Ambient Occlusion ssssssssssesssssse nee 130 1 4 2 Photon Mapping ENEE ence pesca Rb t reper as 131 1 4 2 1 Photon Mapping Concepts 0c cece eee eee eee 131 7 4 2 2 Single Pass Photon Manning 132 7 4 2 3 Two Pass Photon Mapp 132 17 4 3 Final Gathering EEN eee ANEN EENS e 133 74 4 Image Based Lighting sees 133 7 4 5 Subsurface Scattering cece eee eee eee eee 136 7 4 5 1 One Pass Subsurface Bcatieing 00 eee eee 136 7 4 5 2 Two Pass Subsurface Scattering 0 2c eee 138 7 5 Texture Mapping in Linear Space 000s cee eee eens 140 1 6 Baking ceu RR tees e r
121. EFAULT_RIB_RENDERER environment variable to 3Delight8 5 for Houdini versions up to 10 0 473 or to 3Delight9 0 for Houdini versions after 10 0 473 This variable will instruct Houdini to use 3Delight for shader compilation and for rendering and also provides relevant default properties for the RIB output driver Houdini comes with a houdini display driver that can be used with 3Delight This display driver is installed using the proto install Houdini command SDelight provides a digital asset library of all the shaders included in the package Once this file is imported in Houdini all 3Delight shaders will exist as SHOP nodes The digital asset library file can be found in the shaders directory of the 3Delight installation DELIGHT shaders Custom shaders can also be packaged in a digital asset library file which can then be imported in Houdini The sd12otl py Python script that comes with Houdini will parse the output of shaderinfo to create the digital asset library file from any compiled shader file While the RIB output driver comes with the most common rendering parameters several more can be added through the parameter pane s tool menu It is possible to add new parameters remove unwanted ones and save the custom parameter set as the default set to be used for future RIB output drivers This is done through the Save as Permanent Default option of the parameters pane s Tools menu The same mechanism can be us
122. For example setting DL OUTPUT DIR to tmp transforms Display test rif file rgb into Display tmp test rif file rgb This also applies to files generated by RiMakeTexture RiMakeShadow RiMakeCubeFaceEnvironment and RiMakeLatLongEnvironment DL_DUMP_DEFAULTS Forces 3Delight to dump the contents of the configuration file s it reads More on this subject in Section 5 5 configuration file page 59 2 The deprecated DL_RIB_OUTPUT is also accepted for compatibility with older versions Chapter 2 Installation 6 DL_SHADERS_PATH DL_TEXTURES_PATH DL_DISPLAYS_PATH DL_ARCHIVES_PATH DL_PROCEDURALS_PATH DL RESOURCES PATH RIBDIR These variables specify default search paths for different 3Delight resources They can be extracted using the symbol when specifying search paths through RiOption Note that default search paths can also be specified through the configuration file see Section 5 5 configuration file page 59 but setting them through environment variables overrides configuration file defaults This environment variable is set by 3Delight in each RiReadArchive call to the path of the current RIB This lets the user load RIB archives that have a path relative to the parent RIB without using absolute paths For example if the master RIB is scene master rib and the archive to be loaded is scene models car rib one can write the following in master rib to load the archive ReadArchive RIBDIR models car rib
123. Int i n Rt Token i tokens RtPointer i params Prepares a stored object for processing with this API The object must be declared us ing a RiO0bjectBegin RiO0bjectEnd block The i object parameter is the one returned by RiObjectBegin void GxFreeGeometry GxGeometryHandle i geo Release memory and resources that have been allocated by GxGetGeometry This should be done when the object and all the other resources derived from it will no longer be used Chapter 10 Developer s Corner 223 unsigned GxGetFaceCount GxGeometryHandle i_geo Returns the number of faces for a given piece of geometry This can be different from what is specified through the RI interface as 3Delight may transform some types of geometry into a different internal representation int GxCreateSurfacePoint GxGeometryHandle i_geo unsigned i face float i_u float void i v float i time GxSurfacePoint o_point Initializes a surface point handle directly with a face number of parametric coordinates on the face Parameters are i geo The geometry to evaluate i face The face number Must be in the 0 GxGetFaceCount i geo range u v The parametric coordinates on the face local to the face i time Time Currently unimplemented o point A pointer to the handle to be initialized The initialized handle must be cleaned up with FreeSurfacePoint or resources will leak Possible return values all RIE NOERROR Everything went well RIE
124. Interpolation of edges only infinitely sharp creases are added to boundary edges facevaryinginterpolateboundary A per surface value which allows using either true facevarying set to 0 or a facevertex like version set to 1 which smooths out the boundaries The default value is 1 and can be changed in rendermn ini with the 3delight subdivisionmesh facevaryinginterpolateboundary key The following are 3Delight specific extensions smoothcreasecorners This tag requires a single integer parameter with a value of 0 or 1 indicating whether or not the surface uses enhanced subdivision rules on vertices where more than two creased edges meet With a value of 0 such a configuration uses the conventional rules which treat the vertex as a sharp corner With a value of 1 the vertex is subdivided using an extended crease vertex subdivision rule which yields a smooth crease Note that sharp corners can still be explicitly requested using the corner tag Unlike other rendering packages 3Delight does not attempt to tesselate the entire subdivision surface into many small polygons thus taking a large amount of memory instead a lazy and adaptive process is used to generate only those portions of the surface that are needed for some specific bucket All standard variable types are supported constant uniform varying vertex facevarying and facevertex facevertex is used exactly as facevarying but interpolates the variables ac cording to su
125. LOCK ieu ases crx dece eg bag 240 RiMutex UnloCck i22 2bnace d eue Eg Ga 240 RixContext GetRixInterface 239 RixInterface GetVersion 240 RixStorage Get 240 RixStorage Locke 240 EE 240 RixStorage Unlock eee eee 240 RixThreadUtils NewMutex 240 EES iles x EE ERU D ur aaa Ere d 93 kolonii EE 90 BxAttrib te EE 220 RxCachePile eege Ar dae vee bed wi ee er 22 BRxCellNoise eeesithee eue ue mei UE Eque 218 RxEnvironment 22552 p v Sav e DE 220 RxEnvironmentPoints1 219 RxEnvironmentPoints4 ss 219 Rx Pari Fa Giese aie 2 M dde aot aiear tua pedi metu 22 e TEEN 218 Rx ptiOn eere n EEN EEN 220 BxPNO1SO d pede dng EELER d 218 EE EE 219 RxRendererInfo ccc cece etnies 220 EE EE 220 RxShadowPoints1 0 cee cece eee 219 RxShadowPoints4 cece cece eee 219 RXTOXCUNE e eae ond hake ERN RR DAE 220 RxTextureIn 0 5s 0 cease cd vain t EE 220 RxTexturePoints1 sese ees 219 RxTexturePoints4 sees ees 219 RxTransform c c ziigdeacosseev e a aut 220 Rcfranstformboints cece eee eee 220 S SCAM pre d PEE 93 Setcomp sccenrentcadu cde eerte EE 92 EE EEN Ae EE A 92 GT EE 92 Ge EE 92 Share ee RAR paga aie Vaud s 109 SIMU coco Bie lows e eel RE eee Oh rel PER da 90 EE 89 Slo DetailtoStr esee eee 231 Slo End hader esee 231 Slo Gerthonortationbvker sss 231 Slo GetAn
126. P1045 invalid quantize arguments Quantize max is less than max or dithering amplitude is less than 0 P1046 invalid variable variable passed to RiQuantize The variable specified by variable has not been declared Declare it using RiDeclare or use an inline declaration P1047 invalid depth filter a The filter name passed to RiHider is invalid More about hider filters in hider parameters page 31 P1049 unknown RiHider parameter param param is not a valid parameter to RiHider More about RiHider parameters in hider parameters page 31 P1051 filename line invalid context for command The issued Ri command is not allowed in the current context An example would be to issue a RiOption inside the world block P1052 invalid declaration declaration for variable var The variable var is badly declared syntax error P1054 variable type var cannot be assigned to shader variable of the same name but of type type shader is shader and primitive is prim There is a type mismatch between a variable attached to a primitive and its destination parameter in the shader Chapter 9 Error Messages 183 P1055 invalid parameter passed to RiOrientation orientation Only lh and rh are accepted as parameters to Ridrientation RI_LH and RI Bn respectively P1056 invalid parameter passed to RiSides sides RiSides only accepts 1 or 2 as a parameter
127. Range calls should have small overlapping windows Large overlapping windows forces the renderer to keep two model definitions in memory in order to cross fade between them Of course abrupt transitions may cause undesirable geometry pops in ani mation so a fine balance is required Note Different levels of detail can have different rendering attributes This means that costly resources such as displacement maps can be stripped off the lower detail models 7 14 Network Cache 3Delight offers a special extension for more efficient rendering in networked environments a local file cache for textures and archives to minimize network traffic and file server load This proves particularly powerful when using a large quantity of rendering servers The working principle of 3Delight s network cache is to copy files to a local file system and reuse them when needed If either a texture or a RIB archive is cacheable and the file cache is full one or more files are removed from the cache to make space for the new one a LRU Least Recently Used strategy is used to choose which texture s or archive s to remove from the cache Eligibility to caching is different for textures and archives in summary 8 It is also possible to use RiRelativeDetail to modify renderer s detail estimate Chapter 7 Rendering Guidelines 155 Textures Shadow maps Environment maps Cached when accessed through the texture shadow and
128. RiAttributeBegin and restored at RiAttributeEnd Attributes are also implicitely saved at each RiFrameBegin and RiWorldBegin and restored at the enclosing RiWorldEnd and RiFrameEnd Attribute Name Default Comments Color 1 1 1 Default is white Opacity 1 1 1 Default is opaque TextureCoordinates 00 1001 1 1 This option only applies to parametric surfaces such as RiPatch and RiNuPatch Surface defaultsurface This default surface shader does not need a light source to produce visible results Atmosphere Interior Displacement LightSource ShadingRate 1 Default is approximately one shading computa tion at every pixel GeometricApproximation 1 ShadingRate is scaled up by motionfactor 16 motionfactor times the number of pixels of motion This also affects depth of field GeometricApproximation 1 ShadingRate is scaled proportionally to the ra focusfactor dius in pixels of the circle of confusion for depth of field multiplied by this constant Matte 0 Sides 2 Objects are visible from both sides by default Orientation outside Do not invert transform handedness by default TrimCurve m No trim curves defined by default Table 5 4 Standard RenderMan attributes and their default values 5 2 1 Primitives Identification Attribute identifier name Subsequent objects are named as specified by this attribute This is useful when SDelight reports warnings or errors about a primitive Attri
129. RtString i fileName RtInt i nPoints RtInt i firstChannel const RtPoint i P RtFloat Zo result RtInt RxTexturePoints1 RtString i fileName RtInt i nPoints RtInt i firstChannel RtInt i nChannels const RtFloat i s const RtFloat i t RtFloat Zo result Each function takes a texture name and an input point specifying the texture location to be sampled When these are called over all the points being shaded at once proper deriva tives are automatically computed for smooth filtering Otherwise the corresponding function below is called with the same point duplicated four times ie no filtering i nChannels channels is retrieved starting at channel i firstChannel in the texture i fileName Optional parameters described in Table 6 16 provided as name value pairs as accepted Named pa rameters which are varying must be explicitely declared as such inline eg varying float blur or they will be read as uniform All read channels are stored in o result These three functions also have their vector versions RxEnvironmentPointsiV RxShadowPointsiV and RxTexturePointsiV which take a vector of tokens and a vector of values similar to Ri calls A return value of 0 indicates a sucess RtInt RxEnvironmentPoints4 RtString i fileName RtInt i nPoints RtInt i firstChannel RtInt i nChannels const RtPoint i dirO const RtPoint i diri const RtPoint i dir2 const RtPoint i_dir3 RtFloat Zo result RtInt RxShadowPoints4
130. T13 tTACE eg ele domi EE deb RE Webs qu 97 98 EE EE aah hee 92 translater entr ensubu bee iS tien 93 bransmisslOn oc icone deutrespv ves pd EM Ue 98 V VolumeTracer EvaluateStep 243 VolumeTracer GetParameters 242 VolumeTracer InitGrid s 241 VolumeTracer InitRay esee 242 VolumeTracer_StepRay esses 243 VUIansfOIH zc awrckadequpee denen tede 92 X EE EE e AE ae 92 Y EE 92 Z List of Figures 260 List of Figures Figure 5 1 An out of focus moving disk 0 0 cece cece nent e 32 Figure 5 2 A patch of 50000 curves rendered with opacity cull ng 38 Figure 7 1 Ray traced dsplacements 00 e cece ence cence eme 129 Figure 7 2 An image rendered using an HDRI map and the envlight2 shader There is no light sources in the scene the shadows are cast from bright regions in the environment EE 135 Figure 7 3 Teapot rendered with subsurface scattering enabled 00085 136 Figure 7 4 Highly scattering materials long mean free path can benefit from higher shading pU 137 Figure 7 5 Outlines on 0i opacity and z depth Note how outlines get thinner with distance Example scene available in DELIGHT examples toon s sess 151 Figure 7 6 Example of edge detection using normal 152 Figure 7 7 Ri plug in filters lie between the program that generates the Ri calls such as the RIB reader renderdl and the 3DELIGHT ren
131. Variables 00sec eee ee 85 6 2 2 Predefined Light Shader Natalie 86 6 2 3 Predefined Volume Shader Variables 000 eee ee ee 87 6 2 4 Predefined Displacement Shader Vanables 88 6 2 5 Predefined Imager Shader Variables 0000s eee eee 88 6 3 Predefined Shader Parameters 0000 e cece eee rrr 89 6 4 Standard Functions ce ea EE ede A RER EEN 89 6 4 1 Mathematics d ect tb TUER I tere RUE EE EE 89 6 4 3 Noise and Random 20 cece cece eee neces 91 6 4 3 Geometry Matrices and Colors 00 ccc cece ene 92 GAA Lighting decere eg g ree ERR Ee SEN e er vu ebd ide weed nn 94 64 5 Hay Tracing assai sus eee e Seed EE 95 6 4 5 1 Common Parameter 95 6 4 5 2 The trace Shadeop 2 ccc cece eee cnet eee reso 97 6 4 5 3 Other Ray Tracing Shadeops esses 98 6 4 6 Lext re Mapping iem re dE Gidea gander bed ERR EIER 107 6 4 7 String Manipulation AEN EN ENN sees ter rene bow beens 112 6 4 8 Message Passing and Information 113 6 4 9 Co Shader Access sen 119 6 4 10 Operations on Amravs s 119 7 Rendering Guidelines Lsuussusususs 120 7 1 Multithreading and Multiprocessing 00 e cece eee eee 120 TAL Multithreading ee ZE dE ev gea dee oe 120 7 1 2 MultiprocessiBg i i WER bie bade SES ge ceeds A Alege HER Sa 120 7 1 3 Network Rendering eee e eee eee eee eee ener eeee 121 7 1 4 Performance and Implementation Notes 122 7 1 5 Licensing
132. _RANGE Invalid face id RIE BADHANDLE Invalid i geo GxFreeSurfacePoint GxSurfacePoint i point Releases the memory associated with a surface point handle that was previously allocated by GxCreateSurfacePoint int GxEvaluateSurface unsigned i npoints GxSurfacePoint i points RtToken i variable unsigned i width float o values Evaluates a primitive variable at the given surface points inpoints Length of the i points array i_points A pre allocated array of GxSurfacePoints i variable The name of the primitive variable to evaluate eg P Any primitive variable that is attached to the geometry can be evaluated using this function Note that dPdu dPdv N and Ng can always be passed to this function these variables are inherent to the geometry and don t have to be passed as a primitive variable i width The number of components of i variable eg 3 for P o values A buffer to receive the results This should be i_npoints i width long Possible return values are RIE_NOERROR Everything went well Don t worry time stills work in your reality Chapter 10 Developer s Corner 224 RIE_BADHANDLE At least one the the evaluation points is invalid RIE_MISSINGDATA The provided token i varibale cannot be found in the geometry RIE CONSISTENCY i width is not equal to the with of the primitive variable declared in the geometry RIE_BADTOKEN i_variable is of type RtString so it cannot be
133. _methods 1 PrMan doesn t seem to print a header in methods mode else if format e_source 1 We want the source that is output directly compilable So we don tg want the name the shader in the listing else 1 printf s s n Slo_TypetoStr Slo_GetType Slo_GetName if format e_annotations 1 if Slo GetNAnnotations O d fprintf stderr D1GetText D1Text_2261_nokey argv i J continue printf Z d n Slo_GetNAnnotations for int id 0 id lt Slo_GetNAnnotations id const char key Slo_GetAnnotationKeyById id 1 if key assert false fprintf stderr DlGetText DlText 1727 nokey id argv i J return 1 const char annotation Slo_GetAnnotationByKey key printf s _ s n key annotation else if format e_source 1 const char value 10 GetAnnotationByKey source if value 1 printf s n value F Chapter 10 Developer s Corner 239 else 1 fprintf stderr DlGetText DlText 1796 no source else if format e_methods const char const method_names Slo GetMethodNames while method names 1 printf s n method names method names else printArgs format Slo_EndShader return exitCode 10 2 6 The Rix Interface API The Rix API is a collection of classes giving access to useful methods These classes and methods can be used from in
134. a meaning similar to RiShadingRate subsurface referencecamera cameraname Specifies a dicing camera to use when evaluating the subsurface light transport The camera must be declared with RiCamera first as explained in Section 7 12 Dicing Cameras page 153 Chapter 5 3Delight and RenderMan 49 More on subsurface scattering in Section 7 4 5 Subsurface Scattering page 136 5 2 5 Displacement Whenever a displacement shader is applied to a primitive one must specify a displacement bound to inform the renderer about maximum displacement amplitude This is done using one of the attributes described below Attribute displacementbound float sphere radius string coordinatesystem ss name Attribute Attribute Attribute Attribute Attribute Attribute This tells the renderer that a displaced point does not move outside a sphere of a given radius in the given coordinate system The following coordinate systems are supported e surface which is the surface shader s coordinate system e displacement which is the displacement shader s coordinate system e shader which means displacement if a displacement shader is attached to the object and surface if not e current which is the shading language current space e null which specifies the coordinate system active when the attribute call is made e Any other named coordinate system which will be accessible to the object s shaders
135. a pointer to the structure and then traverse the fragments Chapter 10 Developer s Corner 201 PtDspyError DspyImageData PtDspyImageHandle i_hImage int i_xmin int i_xmax_plusone int i_ymin int i_ymax_plusone int i_entrySize const unsigned char i_data if i_data return PkDspyErrorBadParams const PtDspyRawData rawData const PtDspyRawData zi data if strcmp rawData gt ID 3DL return PkDspyErrorBadParams unsigned numFrags 0 fpbx fragments per bucket in x fpby fragments per bucket in y unsigned fpbx rawData gt sppx rawData gt width unsigned fpby rawData gt sppy rawData gt height unsigned numFrags 0 for unsigned i 0 i lt fpby fpbx i PtDspyFragment f rawData gt fragments i we ll skip fragments with a depth of FLT MAX while f amp amp f depth FLT MAX f f next while f 1 numFrags f f gt next b printf total number of fragments d n numFrags Listing 10 2 Accessing lists of fragments deep buffer in display drivers A fragment has the following C declaration Chapter 10 Developer s Corner 202 typedef struct PtDspyFragment_s Fragment color amp opacity float color Thickness of this sample union 1 float thickness float filler F depth of this fragment float depth u v float u v fragment opacity float opacity 3 Next fragment o
136. above copyright notices and this permission notice appear in all copies of the software and related documentation and ii the names of Sam Leffler and Silicon Graphics may not be used in any advertising or publicity relating to the software without the specific prior written permission of Sam Leffler and Silicon Graphics SDelight uses the jpeg library from the IJG It requires that we mention that This software is based in part on the work of the Independent JPEG Group The Windows version of 3Delight uses the regex library The regex license requires the following statements to appear in the documentation of the software The regex library is Copyright copyright 1992 Henry Spencer Copyright copyright 1992 1993 The Regents of the University of California All rights reserved The regex library code is derived from software contributed to Berkeley by Henry Spencer of the University of Toronto Redistribution and use in source and binary forms with or without modification are permitted provided that the following conditions are met 1 Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer 2 Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution 3 All advertising materials mentioning features or use of this s
137. ack function progress cscscrcrceu 40 callback function stop 35 camera EE 66 camera e TEE 153 camera option 29 camerahitmode shading attribute 46 cancelling render callback suus 35 capacity resizable arrays suerrerrrrer 71 categories light 4 cesses eet es 161 caustic shadeop cece e eee eee eee 106 e DEE 47 centered derivatives 0 0 ccc e eee eee eee 52 centered Bikttribute 0 eee eee 52 chaining Ri olue Ans 166 chrome causticn cece eee eee eee 47 cineon display driver 044 173 GO Sbaders EE tens cies irri SE nae ged 68 color bleeding eee eee eee 133 Color Space hsl 2 iie esl RU 65 color space be 65 color space rb 65 color space XyZ sssseee eee eee eee 65 ele EE 65 command line options dsm2tif 21 command line options hdri2tif 22 command line options renderdl 8 command line options shaderdl 11 command line options tdlmake 15 compiled shaders name 11 compiling shaders 0 0000 18 composite hider attribute 46 compressing deep shadow maps Et compressing shadow maps suse 171 coneangle occlusion parameters 102 configuration Die 59 constructive solid geometry sssu 58 corner subdivision surface Lag 54 crease subdivision surface tag
138. alen Scales down the output image Values larger than 1 0 or smaller than 0 0 are not accepted Default is 1 0 preview n Adds a preview image to the texture The preview is the first image in the TIFF file and is written in a format which is readable by most software unlike the mipmaps 3Delight uses The argument is interpreted as an absolute size for the preview if greater than 1 and as a relative size otherwise preview8 n Does the same as preview except that the preview image is always 8 bit This makes it smaller and potentially more compatible with some software quality low medium high Controls mipmap downsampling strategy when using low each mipmap level is created from the previous one At medium quality each level is created from the 2nd previous level At high quality each level is created from up to the 4th previous level The default medium setting is more than enough for most applications Chapter 3 Using 3Delight 18 flips flipt Flips the image horizontally or vertically respectively flipst Flips the image in both directions bakeres n Specifies the output image resolution when converting bake files to a texture map Note that a bake file can be of any resolution but is of the same width and height forcecolor Force greyscale input to be expanded to RGB gamman Indicates the gamma of the input image This allows tdlmake and 3Delight to convert the texture t
139. ame and active in the current attribute scope shader getshaders category string category name Get all co shaders declared in the current attribute scope filtering them using an optional category name shader getlight string light handle Returns the co shader for the light source with handle light handle shader getlights category string category name Returns all active lights in the current attribute scope filtering them using an optional cate gory name This method can be used to build custom illuminance loops For example vector L color Cl C20 shader lights getlights category diffuse uniform float num lights arraylength lights i for i 0 i lt num lights i 1 t lights i light L Cl C Cl Nn normalize L Note that the L vector is automatically inverted by illumiance but in this case one has the responsibility to invert it manually Refer to The Illuminance Construct page 74 for a more explanation about the mechanics of illuminance O and refer to Light Categories page 74 and Section 6 3 Predefined Shader Parameters page 89 for more about light categories float getvar shader coshader string name output type variable A function to access member variables in a specified co shaders see Section 6 1 2 6 Co shaders page 68 Another use of this function is giving it the null shader handle to make it search for the variable directly on the geometr
140. ample dPdtime vector varying How the surface position P is changing per unit time as de scribed by motion blur in the scene Ci color varying Same as Cs Oi color varying Same as Os L vector varying Incoming light ray direction Cl color varying Incoming light ray color Ol color varying Incoming light ray opacity Output Ci color varying Incident ray color Oi color varying Incident ray opacity P point varying Displaced surface position N vector varying Displaced surface shading normal Table 6 5 Predefined Surface Shader Variables Chapter 6 The Shading Language 86 6 2 2 Predefined Light Shader Variables Name Type Storage Description P point varying Surface position on the light dPdu vector varying Derivative of surface position along u dPdv vector varying Derivative of surface position along v N normal varying Surface shading normal on the light Ng normal varying Surface geometric normal on the light u V float varying Surface parameters du dv float varying Change of surface parameters S t float varying Surface texture coordinates L vector varying Outgoing light ray direction Ps point varying Position being illuminated E point uniform Position of the eye ncomps float uniform Number of color components time float uniform Current shutter time as specified by RiShutter dtime float uniform The amount of time covered by this shading sample I vector varying Incident ray direc
141. an 10 units and in a solid angle of Pi 4 hemi occ occlusion P Ng 8 maxdist 10 coneangle PI 4 Same as above but only consider light coming from a hemisphere oriented toward 0 1 0 uniform vector sky vector 0 1 0 hemi occ occlusion P Ng 8 maxdist 10 coneangle PI 2 axis sky color indirectdiffuse point Pt vector R float samples Computes diffuse illumination due to diffuse to diffuse indirect light transport by sampling a hemisphere around a point Pt and direction R Use this shadeop to render color bleeding effects e Pt and R must lie in current space and R must be of unit length e This function makes it possible to lookup into an HDR image when sampled rays do not hit any geometry the map is specified using the environmentmap parameter as shown in Table 6 11 e Computing the occlusion while calling this function is also possible through the occlusion parameter with the following restriction indirectdiffuse only sees geometry tagged as visible to reflections as opposed to occlusion which sees geometry visible to shadows For more informations about visibility attributes refer to Section 5 2 attributes page 44 Note This shadeop will automatically perform final gathering if there is a photon map attached to geometry Using photon maps will speed up global illumination compu Chapter 6 The Shading Language 100 tations tremendously using this
142. ap as a sampling dis tribution to compute image based occlusion float occ 0 uniform numSamples 20 gather illuminance P Nf PI 2 numSamples distribution lightprobe tdl 1 do nothing else occ 1 occ numSamples 6 1 7 4 Functions As in many other languages functions in the RenderMan shading language are re usable blocks of code that perform a certain task The general form of an RSL function is as follows return_type function_name parameters list function body return return_value In traditional shaders see Section 6 1 1 1 Traditional Structure page 62 functions have to be declared prior to their calling points In class shaders see Section 6 1 1 2 Shader Objects page 62 functions can be declared anywhere outside the class or inside the class with functions declared in the class scope being accessible to other shaders An example function is shown Listing 6 5 1 This parameter is somewhat redundant to the environment category In the future environment category will be replaced by a samplepattern category combined with distribution parameter Chapter 6 The Shading Language 83 void print_error string tex printf error loading texture s n tex color tiled_texture string texture_name float u v float num_tiles_x num_tiles_y output float new_u newv color red return color 1 0 0 if texture na
143. apn This options specifies which mipmap level is converted Note that mipmapping can be disabled by an option given to the display driver see Section 8 8 dspy_dsm page 171 8 16 32 float Chooses data format for the output TIFF Default is 8 bits per channel lzw deflate packbits logluv Selects a compression scheme Default is 1zw logluv is only supported with float data type y Prints version and copyright information h Shows help text Chapter 3 Using 3Delight 22 3 5 Using hdri2tif on High Dynamic Range Images hdri2tif uses a range compression algorithm to convert high dynamic range images into dis playable low dynamic range TIFFs All the important HDRI formats are recognized in input 1 Floating point TIFFs as well as LogLuv encoded TIFFs 2 Radiance files uncompressed or RLE packed 3 ILM s OpenEXR files Note that all formats must have 3 or 4 channels The fourth channel is considered to be alpha information and stays untouched in the output image hdri2tif accepts the following options middle gray n key n Sets the value of the middle gray in the image default is 0 18 Range is 0 1 Specify ing a value of 0 enables a histogram based automatic estimation one can use verbose to display the computed key value simple By default hdri2tif uses a dodging and burning algorithm which is relatively costly This option uses a simpler algorithm that is well suited for image
144. aps that are widely used in the industry Generating such shadow maps implies placing the camera at the position of the light source and rendering the scene from that view point zfile or shadowmap display driver has to be selected see Section 8 6 dspyzfile page 170 Chapter 7 Rendering Guidelines 123 and Section 8 7 dspy_shadowmap page 171 for information about file formats used and options The shadow map is then used from inside a light source shader to cast shadows on objects Shadow maps have a number of advantages e They are fast to generate Indeed shadow maps can be generated much faster than a normal color image mainly because only depth information is needed When rendering a shadow map one could remove all surface and light shaders even displacement shaders can be removed if they do not affect the geometry too much Also filtering using PixelFilter command can be lowered even to 1x1 and ShadingRate increased up to 10 or more e They can be reused in more than one render If the scene is static and only the camera moves a generated shadow map can be used for all subsequent renders This often happens in the lighting stage of a production pipeline e They can be used to generate low cost penumbra Specifying an appropriate blur to the shadow call one can simulate penumbra effects see shadow shadeop page 109 e They provide fairly good results when used carefully Many of the recent CG productions use normal
145. aps to render reflections In most cases the viewer won t see the difference Use image based lighting instead of brute force global illumination See Section 7 4 4 Image Based Lighting page 133 If using ray traced shadows use the opaque or Os transmission modes this avoids costly shader interrogations Shaders triggered by a secondary ray traced rays should use a less expensive code Secondary rays can be detected using the rayinfo shadeop See rayinfo shadeop page 117 Use true displacements and motion blur only when necessary in the context of ray tracing Textures It is well known that texture access eats up a significant amount of rendering time Textures are also known to be great resource hogs Do not use oversized textures or shadow maps Appropriate texture or shadow map dimensions depends on final image resolution and should be adjusted by performing experiments Use compressed textures it pays off in most cases Two benefits are less disk usage and less network traffic tdlmake has several options for texture compression see tdlmake options page 15 Use box filtering if possible see texture shadeop page 107 The gaussian filter gives nicer results in general since it is a high quality anisotropic filter but in many cases such as on smooth textures the box filter can be used without any visible quality penalty Increase texture cache memory This is particularly im
146. aring varying arrays follows the same logic but one has to make sure a varying is really needed in such a case a varying array can consume a large amount of memory B Nothing to do with C classes S Although the shader compiler is good at detecting variables that have not been declared properly and turn them into uniforms Chapter 6 The Shading Language 72 NOTE Assigning varying variables to uniforms is not possible and the shader compiler will issue a compile time error Assigning uniforms to varyings is perfectly legal 6 1 5 3 Constant Variables Constant variables were introduced in RSL 2 0 and are meant to declare variables that are initialized only once during the render This type of variables is further explained in Section 6 1 1 2 Shader Objects page 62 6 1 5 4 Default Class Behaviour If no uniform or varying keyword is used a default course of action is dictated by the RenderMan shading language This default behaviour is context depended 1 Member variables declared in shader objects see Section 6 1 1 2 Shader Objects page 62 are varying by default Variables declared in shader and shader class parameter lists are uniform by default Variables declared inside the body of shaders are varying by default Variables declared in function parameter lists inherit the class of the parameter and this be haviour also propagates inside the body of the function This is possible since RSL functions are inlined more on
147. as many threads as there are processors A thread is different from a process in that it runs in the same memory space as the parent process meaning that using many threads on a single image won t affect memory use significantly unlike multiprocessing as explained in Section 7 1 2 Multiprocessing page 120 One can override the number of threads used by passing the p option to renderdl For example renderdl p 3 frame1 rib will use three threads to render an image More about the p option is explained in Section 3 1 Using the RIB renderer page 7 The number of threads can also be specified inside the RIB using a dedicated RiOption For example Option render nthreads 2 will use two threads to render the image 3Delight will assign a small region of the image to each thread started Typically each region will have a size of 2x2 buckets 7 1 2 Multiprocessing A process is different from a thread in that it runs in its own memory space this means that using multiprocessing will generally use more memory resources than a multithreaded render The advantage of using processes instead of threads is that there is very little synchronization overhead between processes and this might lead to faster renders compared to multithreaded renders Multiple processes can be launched using P command line option For example renderdl P 2 image rib will start a render using two processes The way renderdl splits the image in a multi
148. at Complete path to point cloud file Number of variables to save in the point cloud A type for each variable Types are the same as in the shading language point normal color float matrix Etc A name for each variable A world to camera transformation matrix A world to NDC transformation matrix The X resolution Y resolution and aspect ratio of the image int PtcWriteDataPoint PtcPointCloud pointcloud float point float normal float radius float data Adds a point along with its data to a point cloud file pointcloud A handle to a point cloud file as returned by PtcCreatePointCloudFile Chapter 10 Developer s Corner 230 point normal radius Position orientation and radius of the point and data point and normal cannot be null data Array of floats containing data for all variables continuously in memory The data must be of the same size as the sum of sizes of the variables passed to PtcCreatePointCloudFile Returns 1 if the operation is successful 0 otherwise void PtcFinishPointCloudFile PtcPointCloud pointcloud Writes out all data to disk and closes the file 10 2 4 4 API Example An example is available in DELIGHT examples ptc2rib directory This simple application trans forms a point cloud file into a RIB that is renderable using renderdl An example usage is ptc2rib cloud ptc renderdl d 10 2 5 The Slo API Shader interrogation is possible by using the shaderinfo command li
149. at detail in the RenderMan specification the following chapters give only a brief description and some useful implementation details 5 3 1 Subdivision Surfaces Catmull Clark subdivision surfaces are supported by 3Delight All standard tags are recognized hole A per face value tagging faces that are considered as holes The parameter is an array of integers listing the indices of the hole faces corner A per vertex value tagging vertices that are considered semi sharp The tag should be specified with an array of integers giving the indices of the vertices as well as an array of floating point values giving their sharpness Corners are smooth at sharpness 0 0 and grow sharper as the value is increased crease A per edge value tagging edges that are considered as semi sharp This tag is specified with an array of integers indicating the list of vertices that form an edge chain An array of floating point values specifies the sharpness value for each edge in the chain interpolateboundary A per surface value specifying that boundary edges and vertices are infinitely sharp This tag takes an optional integer parameter with the following possible values e 0 No interpolation the default behavior e 1 Full interpolation infinitely sharp creases are added to boundary edges and infinitely sharp corners are added to boundary vertices of valence 2 This is the behavior obtained when the tag is specified without a parameter e 2
150. at the renderer does when executing a Ri command As shown in lines 02 and 03 as soon as as the renderer encounters a plug in filter that handles the Ri command it calls it and exits from the Ri command This means that if the filter doesn t call the Ri command explicitly the execution will not continue down the chain Continuing Listing 7 17 the myRiSphere procedure would look like this if the wanted action is to continue with renderer s RiSphere code RtVoid Example myRiSphereV RtFloat radius RtFloat zmin RtFloat zmax RtFloat tmax RtInt n RtToken tokens RtPointer params 1 Example current plugin Example RifGetCurrentPlugin current plugin m area 4 0f M PI radius radius Call RiSphereV to continue in the filter chain RiSphereV radius zmin zmax tmax n tokens params Note in the code snippet above how we obtain the current active plug in using RifGetCurrentPlugin This is necessary since myRiSphereV is static and only the renderer knows which instance of the Example plug in is running At the end of the function calling the RiSphereV command insures that execution continues normally and that the sphere is rendered 7 17 2 Using renderdl to Load Ri Plug ins The simplest way to load Ri plug in filters is by specifying them as a command line argument to renderdl As explained in Section 3 1 Using the RIB renderer page 7 renderd1 accepts the rif Chapter 7 Rendering Guide
151. ay excluding the void type The general syntax for a static array is type array_name array_size x y z type array_name array_size scalar array_size must be a constant expression and the total number of initializers must be equal or less than array size When initializing an array with a scalar all array s elements are set to that particular value For example float t 4 0 1 2 3 color n 10 1 set first element to 1 1 1 the rest to O Note that the length of the array in the initializer can be omitted in which case the size is deduced from the right hand expression float t 1 2 3 3 create a static array of size 3 The length of arrays can be fetched using the arraylengthO shadeop see arraylength shadeop page 117 float array length arraylength t A particular element in an array can be accessed using squared brackets float t 4 1 float elem 2 t 2 6 1 4 2 Resizable Arrays Resizable arrays are declared using a non constant length or by not providing the array length at all color components empty shader lights getlights color light_intensities arraylength lights one per light Note that arrays specified without a length as shader parameters are not resizable arrays their length is fixed when the parameter is initialized Thus only locally declared arrays can be resizable Additionally initializing an array will define a static array
152. ayArgElement SLO_VISSYMDEF i_array int i_index If a parameter is an array as specified by Slo_GetArgById or Slo_GetArgByName each of its element should be accessed using this function Chapter 10 Developer s Corner 231 int Slo_GetNAnnotations void Return the number of annotations contained in this shader Annotations are further discussed in Section 10 4 Attaching annotations to shaders page 245 char Slo_GetAnnotationKeyByld int i id Returns an annotation key by it s index i_id Acceptable indexes range from 1 to n where n is the number of annotations available Any index outside this range returns 0x0 null pointer char Slo_GetAnnotationByKey const char i key Returns an annotation specified by it s key If i key doesn t refer to any annotation 0 null pointer is returned It is possible to retrieve the different possible keys with Slo GetAnnotationKeyByld void Slo_EndShader void Close the current shader char Slo_TypetoStr SLO TYPE i type Get a string representation of type i type char Slo_StortoStr SLO STORAGE i storage Get a string representation of storage class i storage char Slo_DetailtoStr SLO DETAIL i detail Get a string representation of variable detail i detail const char const Slo GetMethodNames Returns a null terminated array of strings containing the names of the methods in the current shader Next is the complete source code of the shaderinfo utility
153. be called before any other Ri Calls C2047 non closed condition block missing RilfEnd RIB conditions are not balanced properly C2049 filename line premature call to RiMotionEnd Some motion steps have not been described yet An example would be MotionBegin 0 0 5 1 0 Translate 0 0 1 Missing two more steps MotionEnd C2080 RiBegin not called RiBegin should be the first function called when using the Ri API D2002 cannot connect to display driver displayname system error syserror Some entry points are missing D2003 cannot open display driver displayname system error syserror The dso could not be loaded It could be a library problem D2004 failed to open display driver displayname display driver returned gt displayerror Display driver s DspyImageOpen entrypoint returned a failure code A code of 3 is usually for an unsupported combination of number of channels and format A code of 4 usually occurs when the file cannot be created no permission of the directory does not exist D2005 display driver a did not deallocate its data properly Display driver s open returned a failure and did not free the image data D2006 failed to close filename display driver displayname display driver returned displayerror Display driver s close entry point returned a failure code D2007 rendering aborted display driver displayname will be closed Rendering was inter
154. be semi transparent without other objects showing through giving direct control over the alpha channel of the final image trace float bias 01 This bias affects all traced rays The bias specifies an offset added to ray s starting point in ray s direction so as to avoid intersecting with the emitting surface trace int samplemotion 0 By default rays are all launched at the object s shading time However rays traced from an object which has this attribute set are spread over the object s visibility time span so they can see motion blur trace maxdiffusedepth 1 trace maxspeculardepth 2 Specifies the maximum depth for reflections and diffuse bounces Chapter 5 3Delight and RenderMan 47 Attribute light string shadows off Turns automatic shadow calculation on or off for RiLightSources specified after this directive Attribute light integer samples 1 Controls the oversampling of automatic shadows Larger values improve shadow accu racy but slow down rendering Attribute light string samplingstrategy lightsource Controls how 3Delight samples area lights Two values are accepted lightsource When this sampling strategy is selected it is the default 3Delight will run each area light as many times as there are area light samples and will average the result Surface shaders will be provided with L Cl and 01 that are the result of the averaging This method will generally produc
155. ble to flatten a RIB which includes many archives or procedurals this can be done using the callprocedurals option e The resulting RIB is nicely formatted EXAMPLES Output the content of a RIB in gzipped binary format gt renderdl catrib binary gzip teapot rib gt teapot binary rib Do the same using environment variables working in a tcsh shell setenv RIFORMAT binary gt setenv RISERVER teapot binary rib gt renderdl teapot rib Append the content of a RIB to an existing file expanding all procedurals and including all archives gt renderdl catrib callprocedurals frame12 rib gt gt sequence rib Chapter 7 Rendering Guidelines 159 7 16 Optimizing Renderings 3Delight is heavily optimized only state of the art algorithms are used in every area and continuous re evaluation of every functionality against the most recent techniques ensures that every release is a step forward in terms of speed and memory consumption This doesn t mean that no user guidance is required to the contrary carefully chosen options and scene layouts can speed up renderings enormously The following sections give some important advices to that matter Rendering Options Tuning Be careful to select the right options the render the fastest option settings without a quality tradeoff Format image resolution Image size is directly proportional to rendering time that is why it is very important to select the right resoluti
156. blur 0 05 The specialized transmission can be used to test the visibility between two given points it can also be used to render soft shadows Here is an example light source that uses this shadeop 4 Refer to Primitives Visibility and Ray Tracing Attributes page 45 for more about visibility 5 Note that shadow can ray trace shadows only from light source shaders Chapter 7 Rendering Guidelines 127 light shadowspot float intensity 1 color lightcolor 1 point from point shader 0 0 0 point to point shader 0 0 1 float coneangle radians 30 float conedeltaangle radians 5 float beamdistrib 2 float samples 1 float blur 0 float bias 1 uniform vector A to from length to from float cos_coneangle cos coneangle float cos_delta cos coneangle conedeltaangle illuminate from A coneangle 1 float cosangle L A length L color atten pow cosangle beamdistrib L L atten smoothstep cos_coneangle cos delta cosangle atten transmission Ps from samples samples samplecone O0 bias bias Cl atten intensity lightcolor Listing 7 3 Ray traced shadows using transmission 7 3 3 Ray Labels Ray labels are identifiers attached to traced rays Labels are specified using the label optional parameters that is supported by all ray tracing shadeops A shader can then obtain the label of the current ray the
157. bute grouping string membership Specifies group membership of subsequent primitives Beginning the group name with or adds or removes subsequent primitives from the specified group name Spec ifying as the group name resets any group memberships More about grouping in Section 7 3 4 Trace Group Membership page 128 and Section 7 9 Display Subsets page 148 Chapter 5 3Delight and RenderMan 45 Attribute grouping string tracesubset Sets the default group subset for primitives that are shooting a ray This attribute sets the default value if ray tracing functions do not provide any value More about grouping in Section 7 3 4 Trace Group Membership page 128 3 5 2 2 Primitives Visibility and Ray Tracing Attribute visibility integer camera 1 Specifies if an object is visible to primary camera rays Attribute visibility integer trace 0 Specifies if an object is visible to secondary rays traced in the scene It affects rays traced by environment traceO gather and indirectdiffuse This at tribute is obsolete visibility diffuse and visibility specular should be used instead Attribute visibility integer diffuse 0 Attribute visibility integer specular 0 Specifies if an object is visible to diffuse or specular rays Diffuse rays are traced by gather indirectdiffuse and occlusion Specular rays are traced by gather trace and environment Note that th
158. butions vector udir Specifies the orientation of the u direction for the anisotropic ashikhmin shirley and ward distributions This is the directon where roughness applies roughnessv is applied in a perpendicular direction on the surface The udir vector does not need to be strictly tangent to the surface as SDelight will project it on the surface itself float eta Specifies an index of refraction to compute a fresnel effect for the blinn ashikhmin shirley and cook torrance distributions This is optional Chapter 6 The Shading Language 98 and not specifying it is visually equivalent to using a very large index of refraction but faster to compute uniform string environmentmap Specifies an environment map to use as incoming light in directions where there is no geometry uniform string environmentspace Specifies a coordinate system to orient the environment map color environmenttint Specifies a multiplicative factor for the content of the environment map output varying color transmission Returns the transmission in the traced direction This takes into account both coverage if sampling a cone and the opacity of the surfaces hit by rays It is not influenced by the specified environment map There is no speed penalty to get the transmission from trace IMPORTANT The returned value is exactly the same as what would have been returned by the transmission shadeop page 98 with the important difference that transmission de
159. c extensions are discussed in Chapter 5 3Delight and RenderMan page 29 Shading Language SL support and shadeop details are given in Chapter 6 The Shading Language page 62 Rendering tips and useful suggestions can be found in Chapter 7 Rendering Guidelines page 120 3Delight s extensible display driver interface and descriptions of all provided display drivers can be found in Chapter 8 Display Drivers page 168 1 2 Features Here is an overview of 3Delight features RenderMan Compliant The renderdl program can render any RenderMan Interface Bytestream RIB file binary or text formats or an application can link with the 1ib3delight library di rectly and use the RenderMan Application Programming Interface API refer to User s Manual Chapter 5 3Delight and RenderMan page 29 for details RenderMan Shading Language Support Programmable shading and lighting with an optimizing shader compiler RenderMan shaders are fully supported surface displacement light atmosphere interior and im ager Matrices arrays normals vectors and all the standard shadeops are supported DSO shadeops light categories message passing and output variables are also sup ported Shaders can be either compiled or interpreted See User s Manual Section 3 2 Using the shader compiler page 11 Rich Rendering Features Depth of field motion blur level of detail and surface displacement Standard and deep shadow maps as well as ray traced shadow
160. cameras and use them on different objects if desired e A camera will take into account the entire graphical state when declared screen window resolution field of view etc This means that one can control the shading rate of a camera by changing the resolution prior to its declaration lower resolution means higher shading rate e A list of cameras can be specified instead of just one camera In that case 3Delight will tesselate using the camera that is the closest to the rendered objects An example RIB snippet Attribute dice referencecamera faraway closer IMPORTANT Before integrating dicing cameras into your pipeline make sure the problem has been correctly identified Dicing cameras will make your pipeline slightly more complicated and many problematic displacement shaders can be healed by proper programming 7 13 Level of Detail Level of detail gives the ability to specify several definitions of the same model letting the renderer select an appropriate definition considering the size of the model in the rendered image and some user guidance LOD can be thought of as being a mipmapping algorithm that works on geometry instead of textures Chapter 7 Rendering Guidelines 154 As an example to render a forest of trees one might specify two tree models a complex one with detailed structures and leaves and a simpler one with only the basic structures and fewer and most probably bigger leaves The renderer is able to
161. cement Displacement shaders can perturb the geometry of the material by modifying the P and N variables volume Volume shaders are executed in between surfaces or between the eye and some surface for atmosphere shaders to simulate various atmospheric effects They modify Ci and Oi as in surface shaders imager Imager shaders run on the image plane on every pixel They modify Ci and alpha variables light Light shaders are slightly more complicated than other shaders in that they also declare an illuminate construct see The Illuminate Construct page 76 They operate by setting Cl and L output variables 6 1 1 2 Shader Objects The modern structure introduced in RSL 2 0 specifications closely resembles C or Java classes The general structures is as follows class shadername shader parameters 1 member variables declarations member methods declarations F In a nutshell this new structure an example is shown in Listing 6 1 provides interesting capa bilities and some performance benefits 1 Unless they are ambient lights in which case they don t need such a construct Chapter 6 The Shading Language 63 1 Shaders can call methods and access member variables of other shaders only public variables and methods are accessible as expected This feature allows finally to build comprehensive shader libraries that are pre compiled and re usable Intra shader data and method access is perfor
162. coding in the TIFF is not supported Make sure you ran tdlmake on that file Please refer to supported formats page 18 to see what is supported by tdlmake T2039 file filename is not a valid texture file error The file format seems invalid or corrupted T2040 filename not found The specified texture or shadow file cannot be found This usually indicates a problem with search paths T2041 texture texturename was not generated by tdlmake performance and or quality will suffer Textures used by 3DELIGHT work better when generated with tdlmake Chapter 9 Error Messages 193 T2042 filename texture is not adequate for 3delight try using tdlmake 3Delight cannot read the specified texture file directly tdlmake is a utility that can convert pretty much any image file format to a readable texture so it should be tried on the input texture See Section 3 3 Using the texture optimizer page 15 T2087 netcache could not copy file from sourcefile to targetfile When using write caching the output file could not be written back to the network once complete This could be caused by a permission issue or a full target disk T2092 netcache could not update timestamp of file filename When using write caching the file in the cache is touched after being written back to the network This message is shown when this fails most likely because of a permission issue in the cache T2104 netcache
163. cript The command to run then becomes the second argument Forces a display to the framebuffer display driver Note that a framebuffer display driver is added to the displays declared inside the RIB so those are still called If there is already a framebuffer display driver declared in the RIB it is ignored Chapter 3 Using 3Delight 9 D Has the same effect as d but automatically closes the framebuffer display driver when rendering ends id Starts i display and launches the render enabling the user to send multiple renders into a centralized application See Section 8 1 dspy_idisplay page 168 idf Same as id but sets the display to output floating point data nd Ignores all framebuffer display drivers declared in the RIB file s This option overrides id d and D displayvar var Works in conjunction with id d or D to specify which display variable to render For example renderdl id displayvar color aov occlusion test rib The default value for this option is rgba res x y Specifies the resolution to use when rendering the specified RIB This overrides any RiFormat command specified in the RIB file frames fi f2 Renders the frames between f1 and f2 inclusively This options enables you to render some specific frames inside one RIB file Frames outside the specified interval are skipped croplrtb Sets a crop window defined by lr t b gt left right top bottom The values should be given in scree
164. cription Controls the solid angle considered Default covers the entire hemisphere Default is PI 2 If specified and different from vector 0 indicates the direc tion of the light casting hemisphere Rays that are not directed toward this axis are not considered This is useful for specify ing skylights Scales the amount of jittering of the start position of rays The default is to jitter over the area of one micropolygon Default is 1 0 Only consider intersections closer than this distance Default is 1e38 Specifies an environment map to probe when a ray doesn t hit any geometry Specifies the coordinate system to use when accessing the pro vided environment map Default is world Specifies what distribution to use when tracing rays uniform and cosine distributions are recognized One can also spec ify an environment map file that describes the distribution to use an HDRI of the environment is most appropriate for this Finally an array of vectors can be given to specify an arbi trary user generated distribution Default is cosine Not supported in point based occlusion If specified it is set to the color resulting from environment map lookups on unnoccluded samples If no environment map is provided this variable is set to black If specified it is set to the average un occluded direction which is the average of all sampled directions that do not hit any geometry Note that this vector is defined in cu
165. ctBegin i i 2 34 Eeer Deg br E RETE ues 58 Ri bjectInstance closes isses 58 RiParaboloid e ENEE EE EN ede 57 PUP at E 55 RiPatchMeSh ege sade sald EELER HERR Ss 55 RAP OANCS A sis e s ssca REENEN e E an SEN 55 BiPointstGeneralbolvgons 55 BibPoiotebolegons cece eee eee e eee 55 RiPolygOn a Pee Wadden ed Peak ai bre aoi 55 255 RiProcDelayedReadArchive 5T Bibrochenamiclosad cece eee eens 57 Bibrochunbrogram cece eee eee eee 57 RiRunProgram RENE ieties enes 57 RISERVER environment variable 9 RiShadingInterpolation for implicit surfaces EE 56 BEE Ae Aere eege 57 RiTOruS 2 eee nih bebe hea ee nt eens meds A 57 rsl TEE 209 rsl shader structure 62 RunProgram writing a program 214 RX EPI eode erede eI EIL DERE 218 S sample Huption 00 eee eee eee ee 38 samplebase occlusion parameters 102 samplelock hider option 33 samplemotion RiAttribute 46 samplemotion RiHider 0 31 samplepattern gather category 78 samples light attribute ssuesunurrnnn AT samplingstrategy light attribute 47 scattering RiAttribute esses 48 EE 66 search path option 39 second derivatives cece eee eee eee eee 52 self shadowing 0 00005 34 123 semantics multi camera rendering 148 Sense B kttei buten cscs ian y ee Sees ol sgi e EE
166. ctance 1 1 1 This is a multiplier over the reflectance given by the surface shader or the primitive color as specified by the shading model below This can be used to exaggerate or to attenuate the color bleeding effect produced by a particular object Although the difference with the correct illuminance sampling is in many case unnoticeable 2 This include explicit and implicit illuminance loops that are hidden inside shadeops such as specular Chapter 5 Attribute Attribute Attribute Attribute 3Delight and RenderMan 48 photon string shadingmodel matte Sets the shading model of the surface when interacting with a photon Accepter shading models are matte chrome water glass and transparent photon causticmap photon globalmap Specifies a caustic or a global photon map for the current surface This value be retrieved from inside a shader using the attribute shadeop See attribute shadeop page 114 photon int estimator 50 Specifies the total number of photons to use when estimating radiance or irradiance This will be the default value when calling the photonmap O shadeop See photonmap shadeop page 105 5 2 4 Subsurface Light Transport Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute subsurface color absorption absorption color scattering scattering Specifies reduced absorpt
167. cted by the content of rendermn ini On the other hand renderdl is only read by renderdl Each line in the configuration file is of the form key valuel value2 value_n key being the option or attribute in lowercase As illustrated in Listing 5 2 the naming conventions for key are closely related to its RIB binding Additionally each key can be prefixed by 3delight which will make it meaningful to 3Delight only This can prove useful if more than one RenderMan compliant renderer is used in a facility Note that such keys will override the keys that do not have the 3delight prefix as shown in Listing 5 2 Recognized options and attributes are Chapter 5 3Delight and RenderMan 60 exposure 4f 4f geometricapproximation motionfactor f geometricapproximation focusfactor Af shadingrate Af shadinginterpolation je All attributes and options which can be set with RiAttribute see Section 5 2 attributes page 44 and RiOption see Section 5 1 options page 29 can also be set this way A few examples attribute dice hair 1 attribute limits eyesplits 5 option limits othreshold 0 96 0 96 0 96 option netcache cachedir tmp 3delight_cache option netcache cachesize 2000 Default resolution and aspect ratio can be specified for any display driver using the following three keys display displaydrivername xres d display displaydrivername yres d display displaydrivername par f It is possible to s
168. ctory is already created 3Delight uses whatever cached files it contains It is important to use a locally mounted directory since caching network files on a network volume is useless The chosen directory should be dedicated to 3Delight do not put any files in that directory since they can disappear without notice It is possible to disable the cache again by calling the same RiO0ption with a null file name This can be useful in multi frame RIBs Option netcache Cache size is controlled using another Ridption For example to specify 1000 megabytes of network cache use string cachedir Option netcache integer cachesize 1000 Specifying a size which is smaller than the actual cache size causes files to be removed from the cache until the specified size is reached There is no need to specify which files to cache 3Delight detects automatically slow access files and caches them Slow access files are files mounted on a NFS disk or a CD ROM It is also possible to instruct 3Delight to cache some output files by using Option netcache integer writecache 1 This can save a great deal of bandwidth when the output file is going to be reused as the input to another render on the same machine Shadowmaps are a common example of this Even for files which are not going to be reused it is usually more efficient for the file server to receive them in one large chunk Note that because the size of output files is not known in advance th
169. d Type Description resolution uniform float 2 Returns texture map resolution type uniform string Returns type of texture map Can be one of the fol lowing texture shadow environment ptex ture pointcloud brickmap photonmap channels uniform float Returns the total number of channels in the map viewingmatrix uniform matrix Returns a matrix representing the transform from current space to camera space in which the map was created projectionmatrix uniform matrix Returns a matrix representing the transform from current space to map s raster space bitsperchannel uniform float Returns the number of bits used to represent each channel of the texture This is typically 8 16 or 32 pixelaspectratio uniform float Returns the aspect ratio of the pixels in the texture min uniform float Returns the minimum value of each channel over the entire texture max uniform float Returns the maximum value of each channel over the entire texture fileformat uniform string Returns the file format for textures Can be one of tiff openexr or deepshadow Table 6 19 textureinfo field names float float float float float float float atmosphere string paramname output type variable displacement string paramname output type variable incident string paramname output type variable opposite string paramname output type variable lightsource string paramname outpu
170. d by DspyImageOpen page 195 It contains all the channels provided to this display driver out format count The size of the out format character array out format The desired ordering For example bgra If a display driver wants the channels in an bgra ordering it can call this function as follows the formats will be re ordered in place DspyReorderFormatting format count formats 4 bgra DspyMemReverseCopy unsigned char target const unsigned char source int len Reverse len bytes from source to target DspyError const char module const char fmt Output an error message using the specified formatting For example DspyError dspy tiff cannot open file s n file name PtDspyError DspyRegisterDriverTable const char driver name const PtDspyDriverFunction Table pTable This function allows a new display driver to be registered by an application by directly supplying function pointers to the required entry points This is useful when 3Delight is used as a library and the output is to be displayed in the host application For example in 3Delight for Maya we have PtDspyDriverFunctionTable table memset amp table 0 sizeof table table Version k_PtDriverCurrentVersion table pOpen amp MayaDspyImageOpen table pQuery amp MayaDspyImageQuery table pWrite amp MayaDspyImageData table pClose amp MayaDspyImageClose DspyRegisterDriverTable maya_render_view
171. d is an issue triangle 2 0 filterwidth larger than 2 0 is unnecessary gaussian 2 50 A good filter that might produce slightly blurry results not as much as the box fil ter though catmull rom 4 0 A better filter producing sharper textures bessel 6 47660 lanczos Filter width chosen in order to include 2 roots sinc 8 0 lanczos We recommend this high quality filter as the best choice Although it can produce some ringing artifacts on some textures Us ing a filterwidth smaller than 4 is not recommended Table 3 1 tdlmake filters window lt lanczos hamming hann blackman gt Applies a windowing function to bessel and sinc filters which are infinite in width to achieve a softer cut at the filter s support boundaries Possible windowing functions are lanczos hamming hann and blackman By default no function is applied filterwidth n Overrides the default filter width in s and t Important Filter s width is the diameter of the filter and not the radius sfilterwidth n tfilterwidth n Overrides the default filter width in s or t respectively blur n Blurs or sharpens the output image Values larger than 1 0 make the image more blurry and values smaller than 1 0 give sharper looking textures This function works by scaling the filter function by the specified value This is not the same thing as scaling filterwidth Default is 1 0 sc
172. d no ean eee eid es E 141 7 6 1 2D Baking eee EE NEE NENNEN NNN ENEE en 142 1 0 2 3D Baki lg ie shoes set oii Sea dE EE EE E AA 142 7 6 3 Brick Maps Aer dE EE E da dua e eini Per 143 76 4 Baking Using Lights incre E KEE RR ences 143 7 7 Point Based Occlusion and Color Bleeding 0005 145 7 7 1 Difference with Occlusion Baking 0 eee eee 145 7 7 2 Benefits Over Ray Traced Occlusion 0 0002 eee 145 7 7 3 Point Based Imaging Pipeline 0 0 eee eee eee 145 7 7 4 Algorithm Control PDarameters lessen 147 7 8 Multi Camera Bendermg 00 cece eee eens 148 IS DE DEE 148 4 8 2 Limitations 2 2 Ae caves omens connate Mody dee e Pede er DR 148 1 0 Display Subsets 2 saepta Lir EP a piven Se dk Ed 148 7 10 Exclusive Output Variables 0 0 e cece eee eens 149 7 11 Rendering Outlines for Illustrations 0 cece eee eee 150 T 12 Dicing Cameras 3 st esis dees noe SA deed d wea repente 153 7 13 Levelot Detalle eer REENEN SR 153 G14 Network Cache csse orae rete E Red Eo sor C dad enn 154 Ab Eum 156 7 16 Optimizing Renderings 0 cece 159 7 17 Using Ri Plug in Filter 162 7 17 1 Ri Plug in Anatoms 0 c cece eee n eee n rana 163 7 17 2 Using renderdl to Load Ri Plug ins 004 165 B Display Drivers cided ated eh erences 168 8 1 The idisplay display driwer 168 8 2 The framebuffer display driwer 168 8 3 The TIFF display drive 169 8 4 The texture
173. d on points 6 1 2 4 Matrices A matrix in the shading language is a 4x4 homogeneous transformation stored in row major order A matrix initialization can have two forms matrix m matrix space scalar matrix m2 matrix space mOO m01 m02 m03 m10 mii m12 m13 m20 m21 m22 m23 m30 m31 m32 m33 2 Similarly to all RenderMan compliant renderers Matrices declared using Ri calls or in a RIB file are column major Chapter 6 The Shading Language 68 The first form sets the diagonal of the matrix to the specified scalar with all the other positions being set to zero So to declare an identity matrix one would write matrix identity 1 A zero matrix is declared similarly matrix zero 0 Exactly as for point like variables see Section 6 1 2 3 Points Vectors and Normals page 65 matrices can be declared in any standard or user defined coordinate system see Table 6 3 matrix obj_reference_frame matrix object 1 Point like variables can be transformed with matrices using the transform shadoep see transform shadeop page 92 6 1 2 5 Strings Strings are most commonly used in shaders to identify different resources textures coordinate systems other shaders etc A string declaration is of the form string name value One can also declare strings like this string name si s2 sN All operations on strings are explained in Section 6 4 7 string shadeops page 112 6 1
174. d provided that the following conditions are met Redistributions of source code must retain the above copyright notice this list of conditions and the following disclaimer Redistributions in binary form must reproduce the above copyright notice this list of conditions and the following disclaimer in the documentation and or other materials provided with the distribution Neither the name of Industrial Light amp Magic nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE Concept Index Concept Index Se COUCBOLY EE 89 leren EE 89 ionspecular Ae d eee eee eee mime 89 2 2D Wer 110 3 3Deli
175. de io context void SxSetOption SxContext i context const char i optionName Sx Type i option Type SxData i values unsigned i_arraySize void SxSetAttribute SxContext i_context const char i optionName SxType i option Type SxData i values unsigned i_arraySize Sets a rendering option or attribute in the given context All options are accessible from inside the shader through the optionO and attribute shadeops see Section 6 4 8 Mes sage Passing and Information page 113 This is similar in spirit to the RiOption and RiAttribute RenderMan commands Chapter 10 Developer s Corner 225 void i context The SxContext as returned by SxCreateContext i option Type Type of the option i values Pointer to the actual values iarraySize Total number of elements in the array 0 if the variable is not an array Note that all options are uniform SxDefineSpace SxContext i context const char i spaceName float i matrix Binds a matrix to the specified space in the specified context Any name can be specify except current which is reserved by this library This function must be called before SxCreateShader for each space of interest for the new shader SxParameterList SxCreateParameterList SxContext i context unsigned void void void i numPoints const char i spaceName Creates a parameter list for use in either intializing a shader instance or running a shader on a set of points i numPoints specifie
176. derer 0 00 cece eese 163 Listing 5 1 Using sphere shaped Riboints 0 cece cece eee ene nes 56 Listing 5 2 An example rendermn ini De 61 Listing 6 1 En example class shader computing both surface shading and displacement 64 Listing 6 2 An example of a standard point Debt 77 Listing 6 3 An example directional light using solar esses it Listing 6 4 An example usage of the samplepattern category in gather 79 Listing 6 5 An example illustrating the syntax of a RSL function 83 Listing 6 6 specularstd implementation 0 0c 94 Listing 6 7 Baking into a binary Die 110 Listing 7 1 Computing the correct index of refraction for surfaces such as glass 125 Listing 7 2 How to combine ray tracing and environment Mapping ssissrierrrrrrren 126 Listing 7 3 Ray traced shadows using Cransmiesiont esses eee ee 127 Listing 7 4 Ambient occlusion using a lightsource shader 0 eee e cece eee eens 131 Listing 7 5 Using gather to extract lighting information from environment maps 134 Listing 7 6 Simple subsurface shader 0 0c c cece cece eee ent n ee eas 138 Listing 7 7 Example RIB illustrating two pass subsurface scattering eriurrreriu 139 Listing 7 8 Occlusion baking using the bake shadeop 0 00 e cece eee 142 Listing 7 9 Baking using a light source 144 Listing 7 10 An example shader to convert micro pol
177. display driwer 170 amp 5 The IFF display driver escis scinensas dee SEELEN EE nares 170 8 6 The zfile display drtver 00 c cece cence teen eee eees 170 8 7 The shadowmap display drive 171 8 8 The DSM display drtver 0c cece eee nee e nee eeetet eens Td 8 9 Encapsulated Postscript display driwer 172 8 10 Kodak Cineon display driver 0 cee eee eee eee ee 173 8 11 Radiance display driver 0 cece cence eee 173 8 12 OpenEXR display driwer 174 8 13 The PSD display driver 0 0 c cece ene eee eens 175 8 14 The PIC display driver edere et Rex ERE cheated arenes 175 8 15 The JPEG display driwer 176 D Error leet eelere E ege 177 10 Developer s Corner 194 10 1 3Delight Plug ins uoce ere RR ERR Rev ERROR does 194 10 1 1 Display Driver Plug ins 0 cece cece ee ee 194 10 1 1 1 Required Entry Ponts 194 10 1 1 2 Utility Functions ereot rasiri rE AEAEE 198 10 1 1 3 Accessing 3Delight s Deep Buffer 199 10 1 1 4 A Complete sample 202 10 1 1 5 Compilation Directives 0 0 00 eee eens 209 10 1 2 RSL Plugins erreian ete vH E Vea EE TR Iree ORE d TRE 209 10 1 3 Ri Filter Plug ins sees e 212 10 1 4 Procedural Geometry Plug Ans 214 10 1 4 1 The RunProgram Procedural Primitive 214 10 1 4 2 The DynamicLoad Procedural Primitive 216 10 2 3Delight EE 218 10 21 Th Baz APIS EE 218 10 2 1 1 Noise unctions lisse enn 218 10 2 1 2 Texture l
178. dius Call RiDisk instead for more fun RiDisk 0 0f radius tmax RI NULL When running renderdl on the following simple RIB scene 4 renderdl catrib rif example so Translate O O 10 WorldBegin Sphere 1 1 1 360 Translate O O 1 Color 10 0 Sphere 0 5 0 5 0 5 360 WorldEnd D We obtain the following RIB Chapter 7 Rendering Guidelines 167 Translate 0 O 10 WorldBegin Disk 0 1 360 Translate 0 0 1 Color 100 Disk O 0 5 360 WorldEnd Spheres have been replaced by disks as intended Note renderdl uses 3DELIGHT s RifPluginLoad function to load plug in filters Plug ins are unloaded using RifUnloadPlugins These entry points are available to all programs that link with 3DELIGHT and are further described in Section 10 1 3 Ri Filter Plug ins page 212 Chapter 8 Display Drivers 168 8 Display Drivers 3Delight comes with a set of useful display drivers Since 3Delight uses the standard RenderMan display driver interface it is possible to use third parties display drivers also Each display driver is described with more detail in the following sections 8 1 The idisplay display driver This display driver redirects 3Delight s output to i display The i display application is a standalone program designed for image sequence playback when used with 3Delight it enables the user to perform the following tasks 1 Accumulate multiple renders into a centralized ap
179. drivers texture ssseesssssss 170 display drivers IF 169 display drivers ale 170 distribution occlusion parameters 102 DL ARCHIVES PATH environment variable 6 DL DISPLAYS PATH environment variable 6 DL DUMP CORE environment variable 6 DL PROCEDURALS PATH environment variable 6 DL RESOURCES PATH environment variable 6 DL RIB ARCHIVEPROCEDURALS environment variable DEE 5 DL RIB OUTPUT environment variable 5 DL_SEARCHPATH_DEBUG environment variable 6 DL_SHADERS_PATH environment variable 6 DL_TEXTURES_PATH environment variable 6 dodeing and bung 22 doubleshaded Ri ArCtzibute ss ol DSM i206 tise vie raS u a E EEEa REAS REA 123 dsm display driwer kel e EE 21 dso search path 22 Ihm 39 Dspeimageiloset 0 cece eee ee 197 Despeimagebarat 0 eee eee eee 197 Depe Imagelpen cece eee ee eee nne 195 DspyImageQuery eee 194 dynamic output variables ssussurnerne 118 DynamicLoad writing a DSO 216 Concept Index E edges rendering 2 0 e eee eee eee 150 efficiency camera butter 36 encapsulated postscript display driver 172 endofframe RiOntion 00s 40 environment tracing ee eee 125 environment variable 5 environment variables DELIGHT 5 environment optional parameters 109 environment Configuring s ssrsrrrrerrrr
180. e Chapter 8 Display Drivers 172 string nomipmap off Disables or enables mipmapping for this deep shadow map Mipmapping is enabled by default but one could save more than 25 of storage space by using raw DSMs Be careful though since mipmaped DSMs usually produce nicer results especially when viewed from far away string volumeinterpretation discrete Specifies whether the deep shadow map is used to compute shadows cast by solid objects or those cast by participating media fog clouds smoke etc When render ing participating media shadows one should specify continuous to this parameter Default is discrete EXAMPLE Write out a deep shadow map for participating media Display shadow dsm dsm rgbaz string volumeinterpretation continuous There is not need to run tdlmake on files produced by this display driver since they are already in the right format This display is limited to resolutions which are a power of two Particle and volume self shadowing Particles rendered into a deep shadow map will appear as flat objects Thus when viewed from a different location than the light the half closer to the light will not be shadowed while the other half will have self shadowing To work around this problem 3Delight allows shaders to specify the thickness of a surface by outputting a float thickness variable This will spread the opacity computed by the shader over the specified depth around the surfac
181. e 0 10 author Aghiles Kheffache has shadow type toggle version 1 0 Chapter 11 Acknowledgements 247 11 Acknowledgements We would like to thank Moritz Moeller Berj Bannayan Paolo Berto The jupiter jazz group Graeme Nattress Jason Belec Frederick Gustafsson Yu Umebayashi Daniel Moreno Goran Kocov Brian Perry John McDonald and Alexandre Menard for their very helpful suggestions and bug reports Also thanks to Robert Coldwell the creator of the wonderful 3Delighter and Ming Mah for the MacOS X framebuffer And last but not least Jean Jacques Maine always on the front line when it comes to 3Delight testing Chapter 12 Copyrights and Trademarks 248 12 Copyrights and Trademarks 3Delight is RenderMan compliant in that it reads RenderMan RIB files and implements the Ren derMan API The RenderMan R Interface Procedures and Protocol are Copyright copyright 1988 1989 Pixar All Rights Reserved RenderMan R is a registered trademark of Pixar 3Delight uses the libtiff library to read and write TIFF files The libtiff license requires the following statements to appear in the documentation of the software The libtiff library is Copyright copyright 1988 1997 Sam Leffler Copyright copyright 1991 1997 Silicon Graphics Inc Permission to use copy modify distribute and sell the libtiff library and its documentation for any purpose is hereby granted without fee provided that i the
182. e netcache includepaths netcache excludepaths statistics endofframe statistics file statistics mindispbound Default Value 0 225 0 300 horizontal 1 1 0 1 0 1 0 0 0 16 16 256 0 99608 131072 1 1 0 1 0 1 0 256 16 1 10 DELIGHT shaders DELIGHT textures DELIGHT displays DELIGHT archive WW 1000 50 0 Comments old behavior by default shades for every pixel The shutter opens and closes sharply No offset One grid is approximately as large as a bucket when RiShadingRate 1 Enough for most cases larger values may slow down rendering 128 megabytes Consider only opaque objects for z No network caching 1 gigabyte of disk space Has no effect if caching is disabled Output files are not cached No stats Outputs stdout statistics to console Table 5 3 Implementation specific options and their default values Chapter 5 3Delight and RenderMan 44 5 2 Attributes Attributes are components of the graphic state that are associated with elements of the scene such as geometric primitives and light sources As with options there are two kinds of attributes the standard and the implementation specific Standard attributes along with their default values are listed in Table 5 4 Implementation specific attributes are passed through the RiAttribute command and are described in the subsections sections below All attributes are saved at
183. e embed source option This means the 3Delight is able to recompile it on runtime Still re compiling it manually once and for all is a better solution 2073 paramname is not a parameter of shader shader You are trying to set a parameter which is not part of the specified shader 2074 cannot assign variable of type type to parameter typeinshader varname shader shadername SDelight detected a type mismatch between a shader parameter and the value provided for the shader 2088 cannot find dso shadeop shadeop 3DELIGHT is unable to find the DSO that contains the shadeop 2089 cannot load dso shadeop shadeop systemerror 3DELIGHT is unable to load the DSO that contains the shadeop 2090 cannot find func function in dso shadeop shadeop may be missing extern C After loading the DSO 3DELIGHT is unable to get the required function 2100 co shader handle not found in parameter parametername of shader shadername The requested co shader could not be found 2101 bake3d bad value replaced by 0 in file bakefile bake3d was given infinite or NaN values to bake They were replaced by 0 2102 bake3d point with bad geometry skipped in file bakefile bake3d was given infinite or NaN values for a point s geometry That point was skipped 2105 cannot find RtxPlugin plugin 3DELIGHT is unable to find the DSO that contains the plugin 2106 cannot
184. e P vtransform world R return ray transmission env Listing 7 2 How to combine ray tracing and environment mapping 7 3 2 Ray Traced Shadows Before rendering ray traced shadows one should make sure that shadow casting objects those that can obstruct light rays are visible to transmission rays This is accomplished using Attribute visibility int transmission 1 4 Once the visibility flags are correctly set one can compute shadows in many ways 1 By using transmission usually from a light source shader 2 By calling shadow and passing raytrace as a shadow map name 3 By using the automatic shadows functionality Using automatic shadows is the simplest way to render shadows since it requires the addition of only one statement in front of a light source declaration provided that objects are visible to transmission rays Attribute light shadows on LightSource spotlight 1 Using shadow with raytrace as a shadow map name is another simple way to trace shadows without any shader programming and existing shaders that use shadow maps are directly usable In this case user has more control on shadows shape using the blur bias and maxdist options passed to shadow see shadow shadeop page 109 Here is a RIB snippet that uses the standard spotlight shader to compute soft shadows LightSource spotlight 1 string shadowmap raytrace float
185. e The default value is inside Specifying outside reverses the behavior dice rasterorient 1 When raster oriented dicing is off 0 surfaces are diced as if they will always face the camera This is most useful when rendering surfaces that lose displacement details when turned sideways to the camera since micropolygons become big in camera space while they stay small in raster space This feature increases the number of diced and shaded micropolygons which leads to longer render times dice hair 0 This attribute allows direct control over the tesselation in the u parametric direction of curves When set to 0 the width of the curve determines tesselation like other primitives When set to a greater value it is taken as the number of micropolygons to create in the u direction A value of 1 is typically used to render hair dice hairumin 0 This attribute is an alternate form of control over the tesselation in the u parametric direction of curves It specifies the minimum number of micropolygons to create in the u direction Unlike dice hair the actual tesselation can be greater than the specified value It is useful for shaders which require more than one micropolygon to produce the correct look Note that if both this attribute and dice hair are specified the actual number of micropolygons will be the largest of both dice lodreferencecamera Specifies a camera or a list of cameras separated by co
186. e The depth should be specified in current space by the shader For particles using width as the thickness is usually correct surface particle shader varying float width 0 output varying float __thickness 0 __thickness width More shading code SDelight will also automatically compute a thickness for interior and atmosphere shaders It is possible to disable that feature by having the shader output a __thickness of 0 Note that this features requires that the volumeinterpretation parameter of the DSM display driver be set to continuous 8 9 Encapsulated Postscript display driver Use this display driver to produce eps files Those are Postcript files that can be used inside pdf and ps files The alpha channel is ignored in an eps file Only one option is supported uniform string fullimage off When using a crop window this parameter enables the user to create an image of the original size with the rendered crop window placed inside Areas that are outside the crop window are set to black The default value is off Chapter 8 Display Drivers 173 8 10 Kodak Cineon display driver This display driver writes Kodak s Cineon files Each channel is encoded in 10 bits using a logarithmic scale regardless of Exposure and Quantize Such an encoding is appropriate for film recording since it is designed to cover film s color range A color encoded using the Cineon format can be much brighter than whi
187. e aZFile zFile i_hImage if laZFile 1 return PkDspyErrorUndefined h delete aZFile return PkDspyErrorNone h 10 1 1 5 Compilation Directives Here is the compilation command line for the given example zfile cpp Linux g shared o zfile so I DELIGHT include zfile cpp IRIX CC shared o zfile so I DELIGHT include zfile cpp MacOS X g dynamiclib o zfile so I DELIGHT include arch ppc zfile cpp Windows cl I ADELIGHTA include LD zfile cpp 10 1 2 RSL Plug ins It is possible to extend the capabilities of the shading language by calling C or C functions from inside shaders When compiling a shader if the compiler encounters a function it doesn t now it automatically searches all the directories specified by the I command line option see Section 3 2 Using the shader compiler page 11 looking for a DSO containing a definition of the unknown function All this is better explained by an example A sample rsl plugin with two functions one to square float values and another to square point values Chapter 10 Developer s Corner 210 include RslPlugin h include lt iostream gt int float_sqr RslContext rslContext int argc const RslArg argv RslFloatIter retArg argv 0 RslFloatIter argi argv 1 unsigned numVals RslArg NumValues argc argv for unsigned i 0 i lt numVals i retArg argi arg1 retArg arg1 return 0 int point_sqr
188. e correct soft shadows since in most cases light sources are responsable of shadow computation but incorrect lighting illuminance This is the physically correct area light sampling that will run illumi nance based shadeops in all surface shaders as many times as there are area light samples so to ensure a proper BRDF sampling This mode is recommended if e Accurate specular highlights are important e Shadows are generated from inside surface shaders and not light shaders In terms of performance the lightsource mode is obviously slightly faster since it doesn t trigger multiple evaluation of illumiance constructs 5 2 3 Global Illumination Attributes Attribute irradiance nsamples 64 Specifies the default number of samples to use when calling occlusion or indirectdiffuse shadeops This default value can be modified by passing a parameter to those shadeops See Section 7 3 6 Oversampling and Derivatives page 129 Attribute irradiance shadingrate 4 SDelight can use a different shading rate for irradiance computations to speed up occlusion and indirectdiffuse computations Using higher shading rates en ables irradiance interpolation across shaded grids and therefore speeds up rendering Attribute irradiance maxerror 0 1 Controls a maximum tolerable error when using interpolation for an irradiance shading rate higher than 1 Parameter range is 0 1 Attribute photon color refle
189. e can have a sever performance impact it is advised not to touch it unless necessary NOTE Some shadeops contain implicit illuminance loops These shadeops are specular specularstd diffuse and phong These are all described in Section 6 4 4 Lighting page 94 The illuminate Construct The illuminate construct is only defined in light source shaders and serves as an abstraction for positional light casters In a way it could be seen as the inverse of an illuminance construct There are two ways to use illuminate 1 Non oriented Such as a statement is meant to cast light in all directions illuminate point position statement 2 Oriented Such a statement will only cast light from a given position and along a given axis and angle Surface points that are outside the cone formed by lt position axis angle gt will not be lit CI will be set to zero see below illuminate point position vector axis float angle statement Inside the illuminate construct three standard variables are of interest 1 The L variable This is set by the renderer to Ps P This means that L is a vector pointing from light source s position to the point on the surface being shaded The length of L is thus the distance between the light and the point on the surface 2 The Cl variable This variable is the actual color of the light and should be set inside the construct to the desired intensity 3 The 01 variable This is the equivalent of Oi a
190. e light source Both forward and backward message passing can be combined in the same illuminance loop Some default value in case light source has no cone_angle parameter uniform float intensity 2 float cone_angle 1 illuminance P send light intensity intensity light cone angle cone angle d do something with the cone_angle parameter Chapter 6 The Shading Language 76 NOTE Message passing is a powerful feature in the shading language but one has to be aware that improper use could complicate the rendering pipeline fundamentally since it introduces a bi directional flow of data between light sources and surface shaders Working Principles The mechanics of illuminance are straightforward loop over all active lights withing the specified category and evaluate them to compute Cl Ol and L see Section 6 2 Predefined Shader Variables page 84 These variables are automatically available in the scope of all illuminance loops Note that the result of light evaluation is cached so that calling illuminance again within the same evaluation context doesn t trigger re evaluation of light sources This optimization feature can be disabled using a special lightcache argument to illuminate In the example below the evaluation light cache will be flushed and the light sources will be re evaluated illuminance lightcache refresh statements Flushing the light cach
191. e stored The following grid parameters are supported nbattributes A float indicating the number of volume attributes managed by the grid defined by the number of attributes returned by the grid s shaders This is the number of attributes that will be returned by the VolumeTracer_StepRay function cellsize A vector indicating the size of the cells in each dimension nbcells A vector indicating the number of cells in each dimension of the grid This function returns the number of grid parameters successfully retrieved might be 0 if none were requested or a negative value if the grid was not found or the function was called with invalid arguments float VolumeTracer_InitRay uniform string gridName varying point start end varying float stepLength uniform string interpolation Initializes a ray to be traced across the grid Note that this function is SIMD so it will initialize many rays in practice Parameters are gridName Name of the grid in which ray tracing takes place start Starting position of the ray end Ending position of the ray stepLength Approximative length of steps to be made along the ray interpolation Type of interpolation to be used when computing the volume s attributes along the ray The following values are accepted trunc No interpolation sample position is truncated to a grid vertex position This can be useful to simply test the existence of the grid Chapter
192. e there is no boolean type in RSL such as the bool keyword in C scalars are also used to hold truth values e Scalars can be promoted to almost any type For example a color can be initialized with a scalar Ci 1 6 1 2 2 Colors The shading language defines colors as an abstract data type it could be an RGB 3 tuple or an elaborate spectrum definition But until now all known implementations only allow a 3 tuple definition in various color spaces A color definition has the following form square brackets mean that enclosed expression is optional color color name color color_space x y z As an example the following line declares a color in HSV space color foo color hsv 5 5 5 If the space is not provided it is assumed to be RGB color foo 1 set the color to 1 1 1 in RGB space rgb Red Gree and Blue hsv Hue Saturation and Value hel Hue Saturation and Lightness xyz CIE XYZ coordinates yiq NTSC coordinates Table 6 2 Supported color spaces Operations on colors are addition multiplication and subtraction All operations are performed channel per channel Transformation of points between the various color spaces is performed using the ctransform shadeop see ctransform page 92 6 1 2 3 Points Vectors and Normals Point like variables are 3 tuples used to store positions directions and normals in the euclidean 3 space Such a 3 tuple definiti
193. e two closest mipmaps doesn t apply to shadow map lookups This usually achieves higher quality Table 6 16 texture shadow and environment optional parameters type shadow string shadowmap float channel point Pt type shadow string shadowmap float channel point Pri Pt2 Pr Pt4 Computes occlusion at a point in space using a shadow map or a deep shadow map Shadow lookups are automatically anti aliased When using deep shadow maps colored shadows and Chapter 6 The Shading Language 110 void motion blur are correctly computed If the file name passed to shadow is raytrace then ray tracing is used to compute shadows Note that if ray tracing is used only objects tagged as visible to shadows are considered using Attribute visibility transmission Op tional parameters to shadow are described in Table 6 16 Additional information for both shadow maps and deep shadow maps are found in Section 7 2 Shadows page 122 bake string bakefile float s t type value This shadeop writes the given value of type float point or color to a file named bakefile This file can then be converted to a texture map using tdlmake see Section 3 3 Using the texture optimizer page 15 or a call to RiMakeTexture We recommend using the bake extension for files containing such baked data By defaul data is saved in a human readable ASCII format for easy inspection but saving in binary format i
194. eading and returns a file handle than shall be used in other reading calls filename The complete path to the point cloud file nvars A pointer to an int that will be filled with the total number of channels in the point cloud file varnames A pointer to an array of const char that will hold the name of each variable Chapter 10 Developer s Corner 228 vartypes A pointer to an array of const char that will hold the type of each variable Types are string representing the type of the variable as declared in the shading language color point float normal etc This function could fail if the file is not accessible or is not a valid point cloud file in which case null is returned Data allocated by this function is managed by the library and not user intervention is necessary to deallocate it NOTE This API call is badly designed since the caller cannot know the size of var types and varnames in advance But for compatibly reasons with other software we decided to provide this API entry A safe way to open a point cloud file is to call PtcSafeOpenPointCloudFile and then call PtcGetPointCloudInfo to get nvars varnames and vartypes int PtcGetPointCloudInfo PtcPointCloud pointcloud const char request void result This function returns informations about a point cloud file Accepted requests are pointcloud request result A handle to the point cloud file as returned by PtcOpenPointCloudFile The name of
195. ecifies the irradiance entering the surface at this point This is an optional parameter that is used by the renderer to com pute fast approximations in certain contexts The renderer will issue warning R5063 when this parameter is needed but not pro vided usually when combining subsurface scattering and global illumination A good approximation to this value is the diffuse illumination at the surface point Table 6 13 subsurface optional parameters l scale is also normalize is also accepted Chapter 6 The Shading Language 106 float photonmap string mapname point P vector N This shadeop performs a lookup in the photonmap specified by mapname at the surface location described by P N This shadeop accepts the following additional parameters float estimator An integer specifying the number of photons to use for the lookup More photons will give smoother results The default is 50 string lookuptype Can take one of the following values irradiance Returns the irradiance at the specified location radiance Returns the radiance at the specified location Note that 3DELIGHT stores a coarse estimation of the radiance which is not meant for direct visualization It is mainly useful for the indirectdiffuse shadeop when performing final gathering as explained in Section 7 4 3 Final Gathering page 133 float mindepth When performing irradiance lookups specifies the minimum number of b
196. ed to modifiy any object s rendering properties Again it is possible to define a new default set of attributes better suited for rendering with 3Delight than the default properties that Houdini creates by using the Save as Permanent Default option of the parameters pane s Tools menu Chapter 5 3Delight and RenderMan 29 5 3Delight and RenderMan There are two ways to describe a scene to 3Delight the first is by using the RenderMan Application Programming Interface API and the second is by using the RenderMan Interface Bytestream RIB files The RenderMan API and the RIB format are well described in RenderMan Interface Version 3 2 This document is available electronically at https renderman pixar com products rispec index htm A RIB file is a set of commands meant to be interpreted by a RIB reader such as renderdl There is almost a one to one correspondence between the API calls and RIB commands For in depth documentation about RenderMan and the RenderMan API consult the following two classics e The RenderMan Companion Steve UPSTILL Addison Wesley e Advanced RenderMan Creating CGI for Motion Pictures Larry GRITZ and Anthony A APODACA Morgan Kauffman Check http www 3delight com links htm for a direct link to those references 5 1 Options Options are parameters of the graphic state that apply to the entire scene All options are saved at each RiFrameBegin and restored at the corresponding RiFrameEnd call It
197. eee eee eee 21 3 5 Using hdri2tif on High Dynamic Range Image 22 3 6 Using shaderinfo to Interrogate Shaders 00 e eee eee 23 3 Using TIDSHTINK iscriere itoni tn aca e TAG RERE REDERE EE e 24 3 8 Using ribd pends ges d Wee sirs ratie AEN Pep b ea 24 3 0 U smingptc2brick o aee maons he RR EELER EA 26 340 Using ptcVlew ele de dEr Re I CREE ad 26 3l Using cos bebertewised ert dan Reden ini tee 27 4 Integration with Third Party Software 28 Al Autodesk s Maya o eere orbs oe chet NEE Ehre dE es 28 4 2 softimage s AST wisiccidenig etnies hives Ee ERE REIR Rr ERR eS 28 4 3 Side Effects Software s Doud 28 5 3Delight and RenderMan o an anananana nannaa 29 DL EES Sege Ee EE EE 29 5 1 1 Image and Camera Options 0 cece eee eee eens 29 5 1 2 Implementation Specific Option 34 Rendering ODpLboUs onere ene e e pt REO Tet IR ex DUC oes 34 Quality vs Performance Option 37 Search Paths Options 0 00 c eee eee eee eee eens 39 Statistics Options 2 dE NR ketene i9 RP ENEE ERR aet d eae 40 Messages Options cece cece eee hme ee 41 Network Cache Options ssseeseeseeeeee ee 41 User ODptODS geleed RE RE Re EE E SE 41 RIB Output Ontions e n 42 Other Options 2 2 xor breue dE SR get NAR Eat 42 5 2 JAtCFIDUDGS S si eo bro Werde te rer Ree UTER deeb eratis 44 5 2 1 Primitives Identification 00 ccc ccc cece cece ences 44 5 2 2 Primitives Visib
198. eene boacSib dun eee Rep d 90 bc EET 91 EE 90 N LllS6 eek Eug E dE ee rx ades 91 norm alize iil lencbjeg44ege ree ebc4 sateen ss 93 nDUransfOCTm Tor iri ce Rape oth pew epu 92 O RE EE 99 enee 114 DEER 244 01 ub bad ees wet etwas 116 output channel ee ee beer es 118 P EE 94 le EE 106 EE 91 le 119 EEN 90 printfz o s 4 EE deeds 113 PtcClosePointCloudFile 229 PtcCreatePointCloudFile 229 PtcFinishPointCloudFile 230 PrtcGertbointCLoudinfo 20 eee 228 PtcipenboinrCLoudbile 227 PtcReadDataPoint cece eee ee eee 229 PtcSafeOpenPointCloudFile 227 PtceWriteDataPoint lt cece cece eee 229 PCCXtUNe EE 108 EG MER 93 UE 119 R radians eebe EA 89 random sg eos sedge ane was a pian dese anaes whe 91 FAY ANLO EE 117 EE LH ee eege Ae DEus quom 93 E 93 EEN 119 dh DC I E 119 RifAddPlugin iiis sake bene rh ee 9a 213 RifGetChainInfo esses iranda 214 BifGertCurrentblugein srn 213 RifGetDeclaration 0 0 cece cece eee 214 RifGetEmbedding cece cese see ees 213 RifGetTokenName esses sees 214 RifLoadPlugin iecoseme ree br n bep 213 RifParseBuffer eese 214 RifParseFile canalcescans sce he dg 214 RifPluginDeletG6 i i soie eel e 213 258 RifPluginManufacture sess 212 RifRemovePlugin 0 ccc eee eee eens 213 BifUnloadblugins 00 cece eens 213 RiMutex st
199. egory en Matches every light that belongs to at least one category Dech Matches nothing Table 6 4 Valid category terms Follows a simple example illuminance specular amp crowd P d Execute all lights in the specular category but omit the ones that are also in the crowd category Message Passing illuminance can take additional parameters as shown in the general form above These optional parameters are used for message passing and forward message passing Forward message passing is performed using the special send light parameter and is used to set some given light parameter to some given value prior to light evaluation For example uniform float intensity 2 illuminance P send light intensity intensity statements Will set the intensity parameter of the light source to 2 and execute the light overriding the value in light s parameter s list The parameter must have the same type and same class see Section 6 1 5 Variable Classes page 71 in order for the forward message passing to work Getting values back from a light source is done through the same mechanism by using the light parameter prefix For example Some default value in case light source has no cone_angle parameter float cone_angle 1 illuminance P light cone angle cone_angle t do something with the cone angle parameter e Will retrieve the cone_angle parameter from th
200. ent overrides this value Option limits color othreshold 0 99608 0 99608 0 99608 Sets the limit opacity value above which surfaces or layers of surfaces are considered fully opaque This cutoff value enables the renderer to cull geometry more aggressively This threshold can provide significant time and memory savings especially for scenes with a large number of layered and semi translucent surfaces An example is shown in Figure 5 2 Setting this threshold to 1 1 1 disables opacity culling 1 See Advanced RenderMan Creating CGI for Motion Pictures p 151 for a complete discussion about eye splits Chapter 5 3Delight and RenderMan 38 Figure 5 2 A patch of 50000 curves rendered with top and without bottom opacity culling The difference is not perceivable less than 0 4 The full top image took 119 seconds and 63 MB of RAM to render The bottom image took 151 seconds and 80 MB of RAM Option limits color zthreshold 0 99608 0 99608 0 99608 Sets the limit opacity value above which surfaces are considered for depth calculations For any given surface the threshold is checked against the accumulated opacity from the camera up to that surface The default value will cause surfaces to appear in shadow maps only when surfaces behind it are nearly hidden from the camera ie the surface itself or combined with surfaces in front of it is nearly opaque Setting a lower value will make partially transparent surfaces
201. er files 2050 cannot find shader shadername will use default 3DELIGHT was unable to find the specified shader A possible cause is wrong or unset shaders paths refer to Search Paths page 39 3DELIGHT will try loading a default shader to replace the missing one 2051 cannot load shader shadername will use default 3DELIGHT was unable to load the specified shader and will try loading a default shader to replace the missing one 2052 shader shadername is of the wrong type 3DELIGHT detected a mismatch between the Ri call and shader s type such as speci fying a surface shader for a lightsource Chapter 9 Error Messages 189 2068 shader shader uses a different interface version please recompile The specified shader was compiled with a different version of 3DELIGHT and should be recompiled Note that 3DELIGHT can perform automated re compilation if the shader was compiled with the embed source option More about this option in shaderdl options page 11 2069 the interface of shader shader is invalid You have specified an invalid shader to 3Delight Try recompile the shader from the source code 2071 cannot open shader shader 2072 the shader shader uses a different interface version Automatic conversion was successful It should be recompiled for better performance The specified shader was compiled for an older version of 3Delight but it has been com piled with th
202. er ree 33 hider samplelock option 33 hole subdivision surface Lag 54 hsl color space 65 hsv Color Space cuoco dore dc ke v reri ds 65 I idisplay display driver susuusuue 168 iff display driver sii cese rrt tUe er 170 Hf Geet EE 19 illuminance gather category sss 79 illuminance light cache control 76 illuminance working principle 76 illustrations 22 2 eer eee eo 150 image based lighting s usnusurrrrrrrrune 133 image options oec Ee PREX TEE UE PEDE 29 implementation specific options 34 implicit Surfaces iso heec pero ree be pain 56 importance sampling eesessseeees 80 index of refraction esses 125 indirectdiffuse shadeop parameters 101 indirectdiffuse final gathering 99 initialization file renderdl 10 inline archives NES e reet 59 installing 3Delight 000 4 installing on MacOS zx 4 installing on UNI 4 installing on Windows 5 Concept Index EI EE 58 interpolateboundary subdivision surface tag 54 interrogating shaders slo api 230 irradiance lookup photonmaps 106 J jpeg display driver 176 jpeg support in tdlmake 19 L labels ray tracing 0 00000 127 latest version 2 latitude longitude environment maps 15 level of detail 2 aile Re Rer
203. er than the footprint of the intersection point will be replaced 2 Rays in 3Delight carry ray differentials so that it becomes possible to compute the area of the hit point Chapter 5 3Delight and RenderMan 39 by a more efficient proxy A value of 0 can be used to turn this feature off completely This optimization is especially beneficial for higher order surfaces such as subdivisions and NURBS Option trace float depthaffectsptc 1 Specifies if ray depths should be checked when using point based occlusion and color bleeding For example setting Option trace maxdepth 0 will somewhat counter intuitively also disable point based occlusion To enable occlusion indirectdiffuse even in this case one should set this option to 0 Search Paths Options A search path is a colon or semi colon separated list of directories The directories should be separated using a slash character On WINDOWS platforms it is possible to use cygwin s convention c diri Some symbols have a special meaning in a search path string e The symbol specifies the default path Default paths for each resource are settable through the configuration file see Section 5 5 configuration file page 59 or through environment variables see Section 2 4 Environment Variables page 5 Environment variables overrides any value set in the configuration file e The amp symbol specifies the previous path list e A word startin
204. ering pipeline more complicated because of the introduction of an extra step e Not all costly operations are bake able because they change abruptly with scene animation not reusable e Baking might require for the entire render important amounts of storage e Baking requires RIB and shader code modifications and slightly more technical skill That being said baking is widely used in production and could result in important rendering speedups Before baking one must make sure to disable 3Delight s hidden surface removal in order to include in the bake file informations that are invisible in a normal render Visibility culling as well as backface culling when RiSides is set to 1 can be disabled using the following RIB snippet Attribute cull hidden 0 Attribute cull backfacing 0 These two attributes should be set for all primitives for which baking is desired see Primitives Visibility and Ray Tracing Attributes page 45 Additionally it is good to disable the view depen dant dicing so that micro polygons on object s silouettes are properly formed Attribute dice rasterorient 0 NOTE Culling and dicing attributes could have a severe impact on performance they should not be used in beauty main renders 1 Although the error is usually unnoticeable Chapter 7 Rendering Guidelines 142 7 6 1 2D Baking 2D baking is the operation of storing some function into a standard texture map Th
205. erirrreces 123 shadow maps midpoint algorithm 123 shadowmap display driwer 171 Shadows Dias ose sucess sng ERNSTER FERE 34 shadows light attribute susuusrururrren 46 shadows ray tracing 122 126 shadows rendering 0000 122 shadows RiAttribute usussssr eeren 46 shadows sampling option 38 shadows translucent 00 e eee eee 123 shutter efficiency option 36 shutter offset option 36 sides raytracing csset UR RR Rn 96 smooth derivatives 0 cece eee eee ee 52 smoothcreasecorners subdivision surface tag 54 softimage display driwer 175 specularhitmode shading attribute 46 specularthreshold trace option 36 sprite self shadowing sresrusrerrerro 172 stacked displacement shaders 49 standard option 29 Statistics Options c ccesecdcnmsenseceregaretes 40 stereo rendering 00 ee eee eee 148 Stop callback tte heme ERRARE 35 stratified sampling ss ssrsrrrrrrrrrerre 78 Strict rsl Syntax cessi ee areren hira aniani 14 string functions 0c eee eee eee ee eee 112 sub surface scattering 00005 136 sub surface scattering shading rate 137 subdivision surfaces ccc eee eee eee 54 SX EE 224 T tdl make 2 eu eege e pep EE UPREERCEPOLS 15 tdlmake and huge textures snusnurnurnu 20 tdlmake filters uge AE EEN 16 tdlmake
206. ers 175 float exrheader_attrname 0 As above but adds a float attribute float exrheader_attrname 2 0 0 As above but adds a v2f attribute float exrheader_attrname 3 0 0 0 As above but adds a v3f attribute float exrheader attrname 4 000 0 As above but adds a box2f attribute rendermn ini Entries The EXR display drivers recognizes the following parameter display exr compression Contains the default compression to use if no compression mode is passed to the display driver display exr pixeltype Contains the default pixel type to use if none is specified to the display driver display exr asrgba Changes the name of channels written to the file See asrgba in the table above More about the rendermn ini configuration file in Section 5 5 configuration file page 59 8 13 The PSD display driver This display driver writes Photoshop s PSD files Each channel is saved within its own layer either in RGB or in RGBA or in GrayScale All layers use the same format if a layer is in GrayScale all of them are in GrayScale meaning that each specified channel has only one component If only one channel has 3 or 4 components all layers will use RGB or RGBA channels with one component will be converted Layers in Photoshop file format are restricted to 8 bits unsigned per component Declare amb varying color Declare diff varying color Declare spec varying color Quantize amb 2
207. ertain kind of surfaces such as glass it is impor tant to take surface orientation into account to compute the correct index of refraction eta rays exiting a surface should invert the index of refraction as shown in the following code snippet normal Nn normalize N vector In normalize I normal Nf faceforward Nn In float eta 1 3 glass if In Nn lt 0 1 The ray is exiting from the surface inverse the relative index of refraction eta 1 0 eta Compute refracted and reflected ray float kr kt vector reflDir refrDir fresnel In Nf eta kr kt reflDir refrDir Listing 7 1 Computing the correct index of refraction for surfaces such as glass It is often useful to account for an environment map when reflected or refracted rays do not hit anything and this can be achieved using the optional transmission parameter available to trace as shown in Listing 7 2 3 Also known as geometric exposure Chapter 7 Rendering Guidelines 126 color SampleEnvironment point P vector R float blur raysamples string envname First trace a ray and then composite the environment on top if the transmission 0 color transmission color ray trace P R samples raysamples samplecone blur transmission transmission if transmission envname return ray NOTE should apply correct blur here color env environment envnam
208. es RiArchiveBegin RtToken archivename parameterlist RiArchiveEnd Any commands issued between that pair will be recorded as part of the archive archivename They can then be replayed using RiReadArchive or the RiProcDelayedReadArchive procedural 5 5 Configuration file rendermn ini Some of the default options and attributes are settable through the rendermn ini initilization file The renderer looks for it in four different locations in order 1 In 3Delight s installation directory as specified by the DELIGHT environment variable 2 In the directories specified by the DELIGHT CONF environment variable a colon separated list 3 In user s home directory as specified by the HOME environment variable It looks also for an rendermn ini file in the same directory 4 Finally 3Delight tries to load rendermn ini in the current directory If 3Delight encounters the file in more than one location it uses the latest keys and values it finds This enables the user to have a site specific initialization file in the DELIGHT directory and user specific settings in their home directory Note that this file has nothing to do with the renderdl file that is read by the renderdl executable see Section 3 1 Using the RIB renderer page 7 The main difference other than the file format is that rendermn ini is read by 3Delight s core library which means that applications linked with this library including renderdl are affe
209. ese attributes must be specified with inline declarations and take precedence over visibility trace The way objects are shaded when hit by a specular or diffuse ray is specified using hitmode attributes described in hitmode page 46 IMPORTANT gather indirectdiffuse and occlusion functions can trace both specular and diffuse rays depending on the specular threshold as explained in specularthreshold page 36 Attribute visibility string transmission transparent Specifies how an object appears to transmission like rays In particular controls how a specific surface casts shadows on other surfaces Possible values for this attribute are transparent The object does not cast shadows on any other object since it is completely transparent opaque The object casts a shadow as a completely opaque object Os The object casts a shadow according to the opacity value given by RiO0pacity or by the Os variable attached to the geometry if provided shader The object casts shadows according to the opacity value computed by the surface shader This attribute affects rays traced by shadow transmission and occlusion This attribute is obsolete visibility integer transmission should be used instead Attribute visibility integer transmission 0 Specifies if an object is visible to transmission rays See also hitmode page 46 Transmission rays are those traced by shadow and transmission No
210. ess RIB using gzip format This is valid in both ASCII and binary format Only meaningful with catrib callprocedurals Calls any procedurals found in the RIB when outputting Only meaningful with catrib More about procedurals and RIB output in Section 7 15 Outputting RIB page 156 archiveprocedurals Only meaningful with catrib Turns any procedurals found in the input RIB into archives named archive0 rib archivel rib etc maxmessages n Print out at most n warnings and errors to the console For example setting n to five will only show the first five warnings and the first five errors filtermessages m Filter out the messages specified in the comma separated list m Note that this simply sets the message filtering option so it can be overriden by a RIB file See also filtering messages page 41 rif plug in name Loads the specified Ri plug in filter 3DELIGHT will look for the file in the current directory as well as in paths specified in DL RESOURCES PATH and DL_PROCEDURALS_ PATH More about Ri plug in filters in Section 7 17 Using Ri Plug in Filters page 162 rifargs parameters rifend Encloses a set of parameters that are meant for the previously declared Ri plug in filters loaded using rif This set of parameters is not interpreted in any way by renderdl and is directly passed to the Ri plug in filter beep Beeps when all RIBs are rendered beeps Beeps after each RIB is rendered y
211. etwork caching logic T2015 netcache cache directory is located on a slow access device 7a The directory is probably on the network instead of a local drive which defeats the purpose of a network cache 3DELIGHT will still use the specified directory but there might be no performance gains T2016 netcache cannot compute cache size caching disabled The network caching algorithm is not able to compute cache s size For safety reasons 3DELIGHT will disable all network caching logic T2017 netcache cannot perform a locking operations to clean the cache At the end of a render 3DELIGHT s network cache has to perform some maintenance tasks This error message signifies that those tasks were not executed because 3DE LIGHT is unable to get a system lock The effect of this will be generally unnoticeable and could only result in some files being accessed on the network instead of the file cache A possible cause is a restrictrive permission on the network cache directory T2018 netcache cannot resolve path for filename this file won t be cached This is a low level system error If it happens contact us T2019 netcache cannot open lock file lockfile 3DELIGHT needs to access a lock file in the networking cache directory in order to work properly because of potential concurrent renders This means no caching will be performed and that 3DELIGHT will access the file s on the network A possible cause is a restrictrive permissi
212. evaluated 10 2 2 2 Example Usage A complete example can be found in DELIGHT examples gx The directory contains code for a procedural that transforms RenderMan geometry into particles To run the example of a Linux or Mac OS X system open a shell and execute the following commands cd DELIGHT examples gx make A framebuffer should popup and some primtives will be rendered as points The primitives are all described in points rib 10 2 3 The Sx API This API allows the evaluation of RenderMan shaders on arbitrary user data The API doesn t expect any scene description so its usable from a variety of contexts Usage examples include e Evaluation of displacement shaders in animation packages to correctly place fur and hair on a displaced surface e Evaluation of RenderMan shaders on object vertices for a rough preview of RenderMan shaders in an animation package e Using the library to access the high quality and efficient texturing mapping shadeops e Using the library to design other libraries which take RenderMan shaders as inputs This is well illustrated by the VolumeTracer API see Section 10 2 7 The VolumeTracer API page 240 The library operates in SIMD so many points can be evaluated at once 10 2 3 1 Entry Points SxContext SxCreateContext SxContext i parent 0 Creates a shader evaluation context i parent Specifies the parent context void SxDestroyContext SxContext io context Destroys the provi
213. examples sees 20 tdlmake supported formats s crerercus 19 texture display driver 170 texture mapping functions s s cc 107 texture mapping color space 140 texture mapping gamma 140 texture mapping linear space 140 texture maps creating eee 15 texture maps optimizing sssssssse 15 texture memory option 3T texture optional parameters 109 texture3d optional parameters texture3d reading baked data texturesample Hien tea tdlmake aen nes ss Rer heme bnt wee tiff display driwer trace bias attribute 0 e eee eee eee tracesubset attributes 2000 tracing environments eee eee transmission visibility attribute transmissionhitmode shading attribute trim curves trimming sense er Debt iiec scene te oct TEE nie uvae two pass subsurface 0 0 0 e eee eee eee H uninstalling from Windows UNIX installing on user attributes 0 cece eee eee eee eee user defined option V vertex displacement eee eee eee view dependent shading volume self shadowing 08 volume shader performance volumegroupsize RiOption volumeinterpretation DSM display driver W waiting for a license ee eee eee water CAUSTICS sees w
214. ey do not count towards the maximum cache size until they are finished writing This means the cache can temporarily grow larger than the set size so ensure there is some extra space available on the drive used Chapter 7 Rendering Guidelines 156 It is possible to override the network cache s choices about which files are eligible for caching Refer to Network Cache Options page 41 for more information Purging the Network Cache The network cache can be purged manually at any moment if no renderings are running on the machine Simply erase the directory and all its contained files rm rf tmp 3delight cache Using Directory Textures For Large Textures The network caching algorithm copies the entire content of the texture from the server to the local machine which is desirable in most cases In some situations however when the textures are very large but the quality settings are not high enough to see all the details copying the entire texture might be a waste of resources For such cases 3Delight provides directory textures textures saved in a format that permits the caching of data with a mipmap granularity level The format is quite simple the texture becomes a directory with all the mipmap levels saved as individual TIFF files that area cacheable independently Creating such textures is straightforward tdlmake dirtex source tif destination tdl This command will create a directory named destination tdl that contains all
215. faults to intersecting objects visible to transmission rays while trace uses specular rays output varying color environmentcontribution Returns the contribution of the environment map to the output of trace EXAMPLE Trace a ray only considering intersections closer than 10 units Intersection distance is stored in dist and intersection color in c If no intersection dist will be very large float dist color c trace P Nf dist maxdist 10 6 4 5 3 Other Ray Tracing Shadeops float trace point Pt vector R This is an obsolete form which returns the distance to the nearest intersection when looking from Pt in the direction specified by the unit vector R Pt and R must lie in current space This function intersects objects that are visible to transmission rays and is strictly equivalent to float distance trace P dir distance type tranmission color transmission point Pt1 Pt2 Determines the visibility between Pt1 and Pt2 using ray tracing Returns color 1 if un occluded and color O if totally occluded In between values indicate the presence of a translucent surface between Ptl and Pt2 Only objects tagged as visible to transmission rays are considered during the operation using Attribute visibility transmission Section 5 2 attributes page 44 Pt1 and Pt2 must lie in current space When tracing area light shadows it is usually better for perfo
216. following values and is modifiable by the display driver PkDspyFloat32 PkDspyUnsigned32 PkDspySigned32 PkDspyUnsignedi6 PkDspySignedi6 PkDspyUnsigned8 PkDspySigned8 Additionally the display driver may choose the byte ordering of the data by or ing the type with one of the following two values PkDspyByteOrderHiLo PkDspyByteOrderLoHi Modifiable flags to control the way data is sent to the display driver This flag can be set to PkDspyFlagsWantsScanLineOrder to receive the data per scanline instead of per bucket Parameters can be passed to a display driver when issuing the Display command Display render my display rgb string compression zip In this case my display driver receives the parameter compression Chapter 10 Developer s Corner 197 Name Type Count Comments NP SE 16 World to Normalized Device Coordinates NDC transform Nl ES 16 World gt Camera transform near ES 1 Near clipping plane as declared by Clipping far EI 1 Far clipping plane as declared by Clipping nthreads e 1 Number of rendering threads origin p 2 Crop window origin in the image in pixels OriginalSize ue 2 Since width and height provided to DspyImageOpen only re flect the size of the cropped window this variable gives the original non cropped window size PixelAspectRatio T 1 Pixel aspect ratio as given by Format Software s 1 Name of the rendering software 3Delight errorhandler p A p
217. g Output pixel color Oi color varying Output pixel opacity alpha float uniform Output pixel coverage Table 6 9 Predefined Imager Shader Variables Chapter 6 The Shading Language 89 6 3 Predefined Shader Parameters Some shader parameters have a special meaning and should not be used to for a different purpose These are all listed in the table below uniform string __category Only meaningful as as light shader parameters this string specifies the categories to which a light source belongs Light categories are used to control what light sources are considered by constructs such as illuminance and solar For example light donothing string category backlight fog shader body More about light categories in Light Categories page 74 and a real world example is shown in Listing 7 4 uniform varying float __nonspecular Only meaningful as a light shader parameter this scalar specifies to what extent this light contributes in specular specularstd and phong Valid range is 0 1 1 disabling completely the light in the aforementioned shadeops uniform varying float __nondiffuse Only meaningful as a light shader parameter this scalar specifies to what extent this light contributes in the diffuse shadeop Valid range is 0 1 1 disabling completely the light in the diffuse Noteworthy details about __nonspecular and __nondiffuse 1 These two parameters can be either uniform or va
218. g with a and followed by uppercase letters e g HOME is considered as an environment variable and is replaced by its value If the specified variable does not exist it is left untouched in the string e The symbol when placed at the beginning of a path is equivalent to HOME Search paths are specified using the following commands Option searchpath string shader path list Sets shader and DSO shadeops search path Option searchpath string texture path list Sets texture search path Option searchpath string display path list Sets display search path Option searchpath string archive path list Sets archive search path Option searchpath string procedural path list Sets procedural search path Option searchpath string resource path list Sets resource search path This is equivalent to adding this path to all the above search paths Option searchpath string dirmap zone map from map to zone Sets a mapping table for all paths Only entries where zone matches the current dirmap zone are used Then whenever a path begins with one of the map from entries this part is replaced by the corresponding map to The current dirmap zone defaults to UNC on Windows and NFS on all other platforms It can be overridden in rendermn ini see Section 5 5 configuration file page 59 Note the quotes which are escaped here for the RIB syntax In
219. ght features 2 3Delight installing 0 2 eee 4 A absorption Bi Attribute es 48 adaptive occlusion parameters 102 aggregate shadowmap display parameter 171 akncowlecdeements 00 0 eee e eee 247 ambient occlusion 0000 e eee eee eee 130 annotations in shaders eee 245 anti aliasing in ray tracing 129 aperture Control 31 le EE 222 API point cloud 0000 e cece ee ee 227 APL Rx acc rf Eat eg dE AE eb DX bd 218 Eet ENEE 224 approximation trace 0 ee eee eee eee 38 archiveprocedurals option 42 array capaclby ieiesteeserereesiee eeseseririeri yal array EEN 71 array PUSH sue sed pada Sue deed EOE REGEER ral atray TESZ eri dice sd ea pea eninin Fd ruled 70 aspect ratio for patch particles 56 atmosphere shader performance 34 attribute cull backiacng 46 attribute cull bidden 46 attribute derivatives eee eee 52 attribute dice har 52 attribute dice hairumin 52 attribute dice lodreferencecamera 52 attribute dice rasterorient 52 attribute dice referencecamera 52 attribute displacementbound 49 attribute hider composite sssscrcsces 46 attribute irradiance maxerror 47 attribute irradiance nsamples 47 attribute irradiance shadingrate Ar attr
220. h unsigned short m_height unsigned short m_currentLine unsigned short m_pixelsLeftOnLine Chapter 10 Developer s Corner A utility function to get user parameters const void GetParameter const char name unsigned n const UserParameter parms Zort unsigned i 0 i n i if 0 strcmp name parms i name 1 return parms i value D return 0x0 Open PtDspyError DspyImageOpen PtDspyImageHandle i_phImage const char i_drivername const char i_filename int i_width int i_height int i_parametercount const UserParameter i_parameters int i_numFormat PtDspyDevFormat i format PtFlagStuff flagstuff int i bool zfound false const float nl float GetParameter N1 i parametercount i parameters const float np float GetParameter NP i parametercount i parameters RtErrorHandler error handler RtErrorHandler GetParameter errorhandler i parametercount i parameters if error handler 1 could happen if display driver is not run from 3Delight error handler amp stderr error 205 Chapter 10 Developer s Corner 206 Loop through all provided data channels and only ask for the z channel for i20 i i numFormat i 1 if strcmp i format i name z 0 1 i format i type PkDspyNone else i format i type PkDspyFloat32 zfound true if zfound An example on
221. h works well with tiled images Using raw striped non converted TIFFs may degrade overall performance Note that a converted file is a normal TIFF that can be viewed with any image viewer We suggest using a tdl extension for 3Delight texture files Command Line Options tdlmake is invoked by specifying at least two file names and an optional set of command line switches tdlmake options input tif input2 tif input6 tif output tif Valid options are envlatl Generates a latitude longitude environment map envcube Generates a cubic environment map Needs six images in input ordered as follows x X y Y z Z twofish Generates a cubic environment map from two images taken with a circular fisheye lens The first image is taken to be z and the second z lightprobe Generates a cubic environment map from a 360 degree fov lightprobe dirtex Creates a directory texture A directory texture or dirtex in short consists of a series of TIFF files save in a directory along with an index file The main advantage of such textures is to have a finer granularity of data transfer when using the network cache Please refer to Section 7 14 Network Cache page 154 for more about directory textures skymap s Generates a latlong environment map that is a representation of a sky as seen from the given position and the given time The parameter to skypmap is a comma separated list of six arguments specifying lat
222. hader gives the following output 4 shaderinfo matte surface matte Ka uniform float Default value 1 Kd uniform float Default value 1 If the output is intended for parsing it might be better to use the t option which gives the parameters in the following format Line 1 displacement volume surface lightsource imager gt Line 2 lt shadername gt Line 3 A number n specifying the total number of shader parameters Lines 4 to n 4 mi lines of output one for each parameter in the shader Each line is a comma separated list of fields Fields are in order name storage class type default space array length default value If there is no default space lt none gt will be used Interrogating the matte shader with the t option gives the following output shaderinfo t matte surface matte 2 Ka parameter uniform float lt none gt 0 1 13 To find a shader shaderinfo uses the search paths specified by the DL_SHADERS_PATH or DL RESOURCES PATH environment variable Chapter 3 Using 3Delight 24 Kd parameter uniform float lt none gt 0 1 Shader annotation keys are listable using shaderinfo but this feature is better described in Section 10 4 Attaching annotations to shaders page 245 3 7 Using ribshrink ribshrink is a utility to factorize archives from a series of RIB files meaning that parts that are common to all RIBs are extracted and put into archives This tool could drama
223. hadow map creation Putting a limit on the number of visible points can accelerate deep shadow map creation for depth complex scenes The default value is 1 which means that there is no limit on visibility lists lengths Hider hidden float midpointratio 0 5 Allows control over the blending of the z values of the first two samples when using the midpoint depthfilter A value of zero will use the depth of the first sample while a value of one will use the depth of the second sample Values in between blend both depths Hider raytrace int progressive 0 Setting this to 1 enables progressive rendering with the raytrace hider The effect will only be visible with some display drivers such as idisplay Hider raytrace int samplelock 1 This option affects how the random number generator is initialized for some sampling shadeops e g trace When samplelock is set to 1 the seed of the random number generator will be the same for any render which means that any noise perceived in an animation will tend to look static When set to 0 the seed of the random number generation is dependent on RiFrameBegin so the sampling noise will change from frame to frame More detail about the ray trace hider can be found in Section 7 3 7 The Ray Tracing Hider page 130 The photon hider accepts the emit parameters as described in 3 Section 7 4 2 3 Two Pass Photon Mapping page 132 Option Default Value Comme
224. hadow map is slightly less than the distance computed while rendering the image To prevent self shadowing specify a bias which is a value that is added to the shadow map value If bias0 is different from bias1 the renderer chooses a random value between them for each sample Note that those parameters do not affect ray traced shadows The value of bias0 and bias1 should be set to 0 if the midpoint algorithm is used to compute the shadow map see Section 5 1 options page 29 for more details on how to use the midpoint algorithm Option render integer nthreads n Specifies how many threads to use for the render Specifying 0 tells 3Delight to use as many threads as there are processors If the value is negative it is added to the number of processors to compute the number of threads to use Refer to Section 7 1 Multithreading and Multiprocessing page 120 for a more thorough discussion about multi threading Option render string bucketorder horizontal In order to save memory the image is rendered progressively in small groups of pixels refered to as buckets This option specifies the rendering order of the buckets Valid values are horizontal Rendered left to right top to bottom this is the default zigzag Rendered left to right on even rows right to left on odd rows This ordering is slightly more memory efficient than horizontal vertical Rendered
225. he correspond ing attribute in the Ri stream with the exception of integer attributes becoming floating point values in the shader since there is no integer type in SL Two entries in the table require slightly more information shaderdisplacementbound sphere This returns the displacement bound as specified by the __displacementbound_ sphere shader parameter If both displacement and surface shader has such parameters their will simply be added together meaning that they should be de clared in the same space Refer to shader declared displacementbound page 50 Chapter 6 The Shading Language 116 shaderdisplacementbound coordinatesystem Will return the __displacementbound_coordinatesystem Surface shader param eter will be returned if displacement shader has no such parameter Again it is imperative to have the same space in both shaders float option string dataname output type variable Returns the data that is part of the renderer s global option state The operation succeeds if dataname is known and the type is correct in which case 1 0 is returned Otherwise 0 0 is returned and variable is unchanged The supported data names are listed in Table 6 21 User defined options as specified by RiOption see User Options page 41 are also accessible EXAMPLE uniform float shadow pass 0 option user shadow pass shadow pass if shadow pass 1 Y Name Type Description Format uniform float 3
226. he existing one This very useful feature can create shadow maps for point lights rendering all six views to a single shadow map file is much more usable than dealting with six different shadow maps More about his feature in Section 7 2 4 Aggregated Shadow Maps page 124 There is no need to run tdlmake on files produced by this display driver since they are already in the right format 8 8 The DSM display driver This display driver produces deep shadow maps As explained in Section 7 2 Shadows page 122 DSMs support opacity prefiltering and motion blur It is suggested to use DSMs whenever possible float tolerance 0 02 DSMs tend to grow quite large unfortunately The display driver tries to compress them using an algorithm that shrinks file size without exceeding some specified error threshold A value of 0 that is no error allowed produces large DSMs and should never be used and a value of 1 compresses DSMs too much and results are unsatis factory If this parameter is not specified or set to 1 the display driver computes a default value currently always 0 02 string compressionlevel 2 This option turns on additional compression which makes DSMs even smaller without affecting quality 0 means no additional compression is not recommended 1 uses compression which has no significant speed impact 2 is the default and usually creates quite smaller files at the expense of slightly longer generation tim
227. her in this fashion When the object is displaced the innermost shaders ie the ones declared last are run first Chapter 5 3Delight and RenderMan 50 Attribute displacement string detail default This attribute controls how displacement shaders are run on geometric primitives The default value causes them to be run at the finest possible detail level for smooth accurate displacement It is also possible to specify vertex which will cause the displacement shaders to be run on the primitive s vertices for less accurate but faster displacement Note that in that case the calculatenormal shadeop will not work so the normals need to be displaced explicitely 8Delight also allows the displacement bound to be specified as parameters of the displacement shader This is especially useful when using stacked displacement shaders The sphere and coordinatesystem parameters of the displacementbound attribute are simply replaced by two parameters EXAMPLE displacement bumpy float Km 1 amplitude 1 string texturename float __displacementbound_sphere Km amplitude string __displacementbound_coordinatesystem current if texturename float amp Km amplitude float texture texturename s t P amp normalize N N calculatenormal P Note that the parameters can be either computed by the shader as in the example or set when the shader is instantiated The displacement bound s
228. here AttributeEnd Chapter 7 Rendering Guidelines 137 Parts of geometry belonging to the same closed object can be specified anywhere in the RIB as long as they all belong to the same subsurface group Specifying Subsurface Scattering Parameters Subsurface light transport parameters can be specified in two different ways see Subsurface Scat tering Attributes page 48 the first one is by specifying the reduced scattering coefficient reduced absorption coefficient and surface s relative index of refraction the second way is by specifying ma terial s mean free path diffuse reflectance and index of refraction All the provided measures should be given in millimeters The shadingrate attribute has the conventional interpretation and determines how finely ir radiance is sampled in the precomputation phase The default value is 1 0 but larger values should be used for highly scattering materials greatly improving precomputation speed and memory use as shown in Figure 7 4 shadingrate 1 0 4 0 10 0 50 0 Timing 48secs 40secs 33secs 23secs Memory 43Megs 20Megs 18Megs 16Megs Figure 7 4 Highly scattering materials can benefit from higher shading rates The chess piece is translucent enough to use very high shading rates without affecting quality significantly Since geometry is rarely specified in millimeters a scaling factor which is applied to the given parameters can also be pr
229. hile Jeep 22i secu e RE RR E C PR Windows installing on Windows uninstalling from world space X XYZ color SDACeuiciv ebbe a a EE Y yiq color space Z LA Scr M zfile display driwer zmax depth filter 0 0 e eee eee ee zmin depth Dlter eee eee eee zthreshold RiOption 00005 256 Function Index Function Index A EE 90 TEE 89 ANDIENG sos sees Mane ee eu pe aes 94 KEE 93 EE EE 117 TEEN 89 CEET 90 atmosphere tins SNE nasa RR hU HER 114 attribut6 is pA EA E AU AR 114 B BAK crec HERE EN sds EE gave IEEE RS PENE Put 110 Bake DEE 110 DBE EE 95 C calculatenormal eere EE 93 TEE 106 COT EE 90 CellnoiS6 s aar ER hae Guba EE E 91 CHALE EE 226 CHAL CONSE gcse kde sued sans NEESS es 231 GELEET 90 EE 92 CONCAb tele Eegiel DEES 112 TEE 89 transformos ieron e prc ERE x 92 D TEE 89 depth dug ub ee RR RR RR ED ERR A 93 Deriv ene xe nee YR REPRE ETE REI ERU RS 9T determinant 3 cog eil V che 93 E a EE 94 displacement ere biu RARE SURE 114 distance cose e RbLRIATEERE GERIERRINIAY E han 93 DSpyErrfor l Records ke exa e ek der ieee ei 199 DspyFindFloatInParamList 198 DspyFindFloatsInParamList 198 DspyFindIntInParamList 198 DspyFindIntsInParamlist 198 DspyFindMatrixInParamList 198 DspyFindStringInParamList
230. hould lie between 0 and 1 otherwise the return value will be clamped to either p1 or pn The default basis is the catmull rom spline Other possible splines are bezier bspline hermite and linear Any unknown spline is assumed to be linear Any recognized spline may be prefixed by solve such as solvecatmull rom In such a case the shadeop becomes a root solver and may be used as an invert function Du type x Dv type x Deriv type num float denom Du and Dv compute the parametric derivative of the given expressions with respect to the u and the v parameters of the underlying surface Noise and Random noise float x noise float x y noise point Pt noise point Pt float w 1D 2D 3D and 4D noise function type can be float color point or vector pnoise float x period pnoise float x y xperiod yperiod pnoise point Pt Ptperiod pnoise point Pt float w point Ptperiod float wperiod Same as noise but has periodicity period Maximum period is 256 cellnoise float x cellnoise float x y cellnoise point Pt cellnoise point Pt float w Cellular noise functions 1D 2D 3D and 4D random Returns a random f1oat color or point Returned range is 0 1 Can return uniform or varying values Here is a trick to put a random color in each grid of micropolygons This spline may also be selected with catrom or
231. i name RtPointer o result RtInt i resultLen RxInfoType_t Zo resulttype RtInt Zo resultcount RtInt RxRendererInfo RtString i name RtPointer o result RtInt i resultLen RxInfoType_t Zo resulttype RtInt Zo resultcount RtInt RxTextureInfo RtString i texture RtString i name RtPointer o result RtInt i resultLen RxInfoType t o resulttype RtInt Zo resultcount The information i name is retrieved and stored into o result which has a size of at least i resultLen in bytes The type is returned in o_resulttype and the number of base elements of type RtString or RtFloat contained in o_result is stored in o_resultcount These two values may be useful for user defined attributes or options For RxAttribute and RxOption a return value N gt 0 indicates that the call failed due to a too small buffer N indicating the number of missing bytes In this case take a look at o resulttype and o resultcount for more explanations A return value of 0 indicates a success A negative return value indicates an error Chapter 10 Developer s Corner 221 10 2 1 5 File functions RtString RxCacheFile RtString i_filename This function allows access to 3Delight s network cache see Section 7 14 Network Cache page 154 When the network cache is enabled the given file is cached and a path to the cached file is returned If caching fails is disabled or is not required i filename is returned This function is useful when the caching of extra res
232. ians and is measured from the axis specified by dir an angle of zero implies that all rays are shot in direction dir and an angle of PI 2 casts rays over the entire hemisphere gather stores its result in the specified optional variables which depend on the specified category The table below explains all supported categories and related output variables samplepattern This category is meant to run the loop without ray tracing and without taking any further action but to provide ray s information to the user This is useful to get the sampling pattern of gather to perform some particular operation In this mode one have access to the following output variables ray origin Returns ray s origin ray direction Returns ray s direction Not necessarily normalized sample randompair Returns a vector which contains two stratified random variables that are well suited for sampling Only the x and y component of the returned vector are relelevant and the z component is set to zero effectivesamples Returns a varying float which is the number of samples effectively used by SDelight This may be different from the requested number of samples Listing Listing 6 4 combines samplepattern and simple transmission queries see transmission shadeop page 98 to compute the ambient occlusion 19 Interestingly this is the only construct in the RenderMan shading language that explicitly relies in its standard fo
233. ibute light samples 0 47 attribute light samplingstrategy 47 attribute light shadows 06 46 attribute maxdiffusedepth 46 attribute maxspeculardepth 46 250 attribute procedural reentrant 53 attribute shade diffusehitmode 46 attribute shade frequency ssrersreres 53 attribute shade shadingrate 53 attribute shade smoothnormals 53 attribute shade specularhitmode 46 attribute shade transmissionhitmode 46 attribute shade volumeintersectionstrategy 53 attribute sides backfacetolerance 51 attribute sides doubleshaded 51 attribute subsurface absorption 48 attribute subsurface meanfreepath 48 attribute subsurface reflectance 48 attribute subsurface scattering 48 attribute trace bas 46 attribute trace samplemotion 46 attribute trimcurve genge 51 attribute user 51 attribute visibility camera 45 attribute visibility diffuse suse 45 attribute visibility photon 45 attribute visibility specular 45 attribute visibility subsurface 45 attribute visibility trace 000 45 attribute visibility
234. ic primitive bypassing all shaders This is likely to be slower to compute than getting a similar variable from another shader 6 4 10 Operations on Arrays void resize output type Al uniform float length Resizes the array to the specified length e Increase array length will leave the new elements uninitialized e length is always uniform e If length is set to 0 the memory held by the array is released void reserve output type Al uniform float length Increase array s capacity if necessary without affecting it s length void push output type Al type value Increase the array length by one and initializes the last element to value type pop output type Al Returns the last element of A and decreases array s length by one The capacity of the array is not decreased Chapter 7 Rendering Guidelines 120 7 Rendering Guidelines 7 1 Multithreading and Multiprocessing 3Delight can render an image using both multithreading and multiprocessing Additionally 3Delight is able to render an image using any number of machines that are reachable on the network and po tentially using many threads or processes on each machine This very complete set of functionalties makes 3Delight usable on any multiprocessor hardware configuration This section explains threading and multiprocessing in more detail and gives hints on when to use one or the other 7 1 1 Multithreading By default 3Delight starts the render using
235. if it was not possible to have a different alpha channel for each display when rendering a foreground and a background one expects to be able to composite the two layers together This is achieved by adding the alpha channel to the display Display foreground tif tiff rgba string subset foreground Display foreground_ambient tif tiff color ambient alpha string subset foreground 7 10 Exclusive Output Variables IMPORTANT Although this functionality is still implemented and useful in some occasions we consider that the display subsets feature see Section 7 9 Display Subsets page 148 supersedes exclusive output variables and offer even more flexibility By Moritz Moeller 3Delight possesses the ability of rendering data to an arbitrary number of so called secondary displays usually image files on disk These displays are fed with certain variables from shaders attached to the geometry Since any variable in a shader can be used to output data this way they are also called Arbitrary Output Variables or AOVs for short The main use of AOVs is decomposing the inner workings of a shader for later recombination in a compositing package where each AOV can be altered rather quick compared to the time it would require to re render a beauty image containing all of them combined into a final and more or less fixed result However AOVs come with two problems Firstly every shader that doesn t write to a
236. ified Here is an example shader that will trigger the execution of the baking light surface plastic 1 Ci i j execute light sources in the bakelight category illuminance bakelight P nothing to do here D D In this case the light source should be attached to the scene during the backing pass and detached in the beauty pass This process can be made somewhat easier by using a user option to enable the light during the backing pass and disabling it in the beauty pass so to avoid light linking operations between passes The illuminance call then becomes float enable 0 option user bakepass enable illuminance bakelight P send light do_bake enable Executing all light sources can have an adverse impact on performance Chapter 7 Rendering Guidelines 145 In this case the user has to properly set the bakepass boolean to 1 during the bake pass and to during the beauty pass The send command will set the do bake parameter of the light source using forward message passing 7 7 Point Based Occlusion and Color Bleeding Point based graphics reply on a dense point set approximation of scene geometry to compute effects such as occlusion and color bleeding It is a two pass process that consists of a rapid geometry conversion step followed by the main render The following sections explain the particularities of those algorithms and show how to use 3Delight s poi
237. ile color ptc The shader can then access these parameters using the attribute shadeop see attribute shadeop page 114 Another solution is to use a light source to perform the baking The main advantage of using light sources instead of user attributes is that most 3D packages have an easy way to perform and visualize light linking so one can easily attach a light source to parts of a scene that needs to be baked Chapter 7 Rendering Guidelines 144 light bakelight bool do_bake 0 0 string bake_file float bake_color 0 0 string spacename world string __category bakelight 1 if do bake 1 0 amp amp bake file 1 if bake color 1 1 color C 0 surface Ci C bake3d bake_file Ps Ns interpolate 1 coordsystem spacename Ci C else bake3d bake_file Ps Ns interpolate 1 coordsystem spacename Listing 7 9 Baking using a light source The light source in Listing 7 9 above can bake both the color for color bleeding or the area for occlusion It uses the surface shadeop to get Ci from the surface shader that is executing the light source This means that the light source has to be executed after Ci has been computed The execution of a light source can be triggered explicitly using the illuminance construct but one should avoid executing light sources that are not meant for baking and that is why a __category string is spec
238. ility and Ray Tracing 00005 45 5 2 8 Global Illumination Attributes 0 0 0 47 5 2 4 Subsurface Light Transport 48 5 2 5 Displacement c irae SN epu Dhaka DRE E ERR 49 52 6 User Attrib tes bere ep ev erae pan eno HO oig 51 5 3 7 Other Attribules eere e e ere ee E RE RR E ees bl 5 8 Geometric Primitives 0 0 0 0000 ccc ccc cece e 54 5 3 1 Subdivision Surfaces 0 00 0 c cece cee eens 54 5 89 2 Parametric Patches 0 0 000 ccc cece cece eens 55 GE E e EE 55 5 3 4 Polygos eate Cane Arel Pu eeu Med du 55 DoD ONUS tss hrene ee su ea etat es 59 5 3 6 Implicit Surfaces Blobbies sees 56 dE QuadriS ER 57 5 3 8 Procedural Dmutu xveng 0 000 57 5 3 9 Object INSTANCES 0 cece eee nee 58 5 3 10 Constructive Solid Geometry 0 0 eee eee 58 5 4 External Resource 58 SAL Texture Maps e iecndcathetind rabat dedit epa ee 58 SA2 Archives regire estet tee eevee bebe bere ette d e eb Ae 59 5 4 2 1 RiArchiveRecord ssssssseeee e 59 5 4 2 2 Inline Archives iiir red d M EIN E RUE CR E ER dees 59 5 5 Configuration file rendermn ini sees eese 59 6 The Shading Language esses 62 6 1 Syntax cds ipribrebe beer ueteres epe ee pae dA ba d ed 62 6 1 1 General Shader Structure 62 6 1 1 1 Traditional Structure ice rrii Ree exea 62 GL Shader Objects cssc bir ehe haerere PG peres 62 0 L2 Variable Types itt Rep S Ah eq
239. in the file name The accepted special codes are UE Is replaced by current frame number specified by RiFrameBegin Chapter 5 3Delight and RenderMan 3l RiHider Display frame f tif tiff rgb ts Is replaced by the sequence number This number is incremented at each RiFrameBegin regardless of the frame number provided Sequence num bering starts at 1 Hn Is replaced by the running sequence number a counter that is incre mented at each RiWorldBegin First value is 1 td Is replaced by the display type The file name in the following example is set to image tiff Display image d tiff rgb dtr Is replaced by 3delight renderer s name HP Is replaced by a Special codes which print numerical values can contain an alignment specifier after the P as in frame 5f tif which would yield frame00001 tif It is also possible to output only a single element of an output variable by using the following syntax Display file tif tiff color many colors 6 2 This would output the element at position 2 in the array of 6 colors named many colors To compute an alpha channel specific to a given AOV simply add the standard alpha variable Display foreground tif tiff color foreground alpha RiHider supports the hidden hider as well as the raytrace and photon hiders refer to Section 7 4 2 Photon Mapping page 131 The optional parameters
240. increasing or decreasing Y Default is increasing When writing an image in decreasing Y order the display driver has to buffer the entire image before writing it to the file This could require a significant amount of temporary disk space uniform string exrpixeltype half Specifies the precision of image data in the file Set to float for full precision at the cost of larger files int asrgba 0 When set to 1 the channels will be recorded as Y RGB or RGBA instead of being named based on the variable being output This only works for 1 3 or 4 channels and is useful for compatibility with poor software int autocrop 0 When set to 1 this will shrink the data window of the file to the smallest window containing all non black pixels Since there is less data written to the file other applications may load it faster This option causes the data to be buffered as for exrlineorder string comment Attaches a comment to the produced EXR file string exrheader_attrname Adds a string attribute named attrname which can be any desired name to the file s header int exrheader attrname 0 As above but adds an integer attribute int exrheader attrname 2 0 0 As above but adds a v2i attribute int exrheader attrname 3 0 O 0 As above but adds a v3i attribute int exrheader attrname 4 000 0 As above but adds a box2i attribute Chapter 8 Display Driv
241. ing because all callbacks are static RifEmbedding RifGetEmbedding Says whether this plug in is run in RIB output mode or in normal rendering mode For example when executing renderdl with the catrib option plug ins are in RIB output Chapter 10 Developer s Corner 214 mode A particular plug in might choose to act differently depending on the embedding RifEmbedding is defined as follows typedef enum k_RifRIB k_RifRenderer RifEmbedding RtInt RifGetDeclaration RtToken i token RiflokenType i token RifTokenDetail i detail RtInt zo array len A helper function to parse Ri in line declarations RtString RifGetTokenName RtToken i token Another helper function to parse in line token declarations This one returns the name of the token or null if the declaration is invalid The returned name does not need to be freed RtVoid RifGetChainInfo RtInt o current RtInt Zo total This procedure returns the current level in the Ri plug in filter chain as well as the total number of plug ins in the chain Range of the o current variable is 0 o_total 1 RtVoid RifParseFile const char i filename RifParseMode i mode This procedure enables a Ri plug in to easily parse RIB files The i mode variables tells 3DELIGHT where in the Ri plug in filter chain the RIB stream should be inserted k RifParseNextLayer Inject RIB stream into next plug in filter in the chain k RifParseThisLayer Inject RIB stream back
242. ing the bake3d shadeop see bake3d shadeop page 110 bake3d occ ptc P N surface color Ci The saved values can be read back using the texture3d call see texture3d shadeop page 111 color res 0 texture3d occ ptc P N surface color res The interface to the bake3d shadeop is richer than the one for bake shadeop as it is possible to specify more than one data channel per 3D point among other things NOTE Point cloud files created with the bake3d shadeop can be viewed using the ptcview utility Implementation Details In contrast with other implementations 3Delight s point cloud files can be loaded partially in memory and efficiently accessed using a caching mechanism similar to renderer s 2D texture caching system Chapter 7 Rendering Guidelines 143 This is important since point clouds can become quite large Additionally point clouds can be read anytime during their creation a shader that issues a bake3d call can also call texture3d on the same file In other words a point cloud file is always in a readable state 7 6 3 Brick Maps Point cloud files are stored in a sparse data structure that is not suited for filtered lookups This means that accessing point cloud files could result in aliasing The solution is to convert the point cloud file into a mip mapped 3D texture similarly to the 2D textures produced by tdlmake Such 3D textures are commonly called brick maps and
243. ings e All internal filtering algorithms are executed in floating point to preserve as much accuracy as possible e An efficient caching system is used to keep memory usage footprint very low tdlmake was tested on textures as large as 16K x 16K 1 Gigabyte of disk space and accomplished its work using less than 12megs of memory e The filtering process has been designed to have a linear cost increase relative to filterwidth unlike some software in which the cost is quadratic For example filterwidth 8 runs twice as slow as f ilterwidth 4 Working with Large Textures As mentioned tdlmake has been designed to adapt very well to huge textures One exception is compressed TIFFs that have a large rows per strip value Here is an example output of tiffinfo on a large texture file that can cause problems for tdlmake tiffinfo earth tif Image Width 43200 Image Length 21600 Resolution 72 72 unitless Bits Sample 8 Compression Scheme AdobeDeflate Photometric Interpretation RGB color FillOrder msb to lsb Software ImageMagick 5 5 7 07 22 03 Q16 http www imagemagick org Document Name earth tif Orientation row 0 top col O lhs Samples Pixel 3 Rows Strip 21600 Planar Configuration single image plane Predictor horizontal differencing 2 0x2 There is only one strip made of 21600 total image height rows This means that accessing any scanline in this TIFF forces the TIFF reading library to uncompress the ent
244. int cloud s 7 7 3 Point Based Imaging Pipeline Since point based algorithms work on point clouds one need to convert scene s geometry to such representation This implies a first pass where polygons surfaces and other geometrical primitives are converted to a point cloud and a second pass where the point cloud is read back and used to compute the occlusion or color bleeding effects Point Cloud Creation Converting a scene into a point cloud representation is a straightforward task but care must be taken to ensure the correctness and the optimality of the operation One should start by disabling all the culling operations to ensure that backfacing and hidden surfaces are not rejected by the renderer prior to shading Chapter 7 Rendering Guidelines 146 Attribute cull hidden 0 Attribute cull backfacing 0 Additionally one should use a dicing method that is independent from the camera view to have correct sampling of points on objects silhouettes Attribute dice rasterorient 0 Since the quality of the image is not important during this first pass one can lower the filter size for fast rendering PixelSamples 1 1 PixelFilter box 1 1 Since no shading is performed during this pass all surface shaders can be removed from the scene and replaced by a shader that converts micro polygons to points The general structure of such a shader is given below A simple surface shader to write out the micro polygons
245. into a point cloud file surface ptc write string ptc file default ptc string ptc coordsys world 1 bake3d ptc file P N coordsystem ptc coordsys interpolate 1 Ci Cs b Listing 7 10 An example shader to convert micro polygons into a point cloud There is many points of interest in Listing 7 10 1 bake3d saves the points as disks and not dimensionless points This is performed by taking the area of each micro polygon using surface derivatives If needed it is possible to manually specify the area of a micro polygon to bake3d float A area P dicing bake3d ptc_file P N coordsystem ptc_coordsys area A interpolate 1 It is suggested not to specify the area channel if it is equal to area P dicing see area shadeop page 93 since this will increase the size of the point cloud file unnecessarily 3Delight already stores that area in the point cloud file 2 The interpolate parameter passed to bake3d is important since we wish to convert micro polygons to points we are interested in micro polygons centers and not corners see bake3d shadeop page 110 Omitting this parameter may lead to unexpected results in the point based occlusion algorithm Surface shaders that contain displacement should be treated with care or replaced by displacement shaders Chapter 7 Rendering Guidelines 147 3 The normal passed to bake3d is no
246. ion along v N normal varying Surface shading normal Ng normal varying Surface geometric normal I vector varying Incident ray direction E point uniform Position of the eye u v float varying Surface parameters du dv float varying Change of surface parameters S t float varying Surface texture coordinates ncomps float uniform Number of color components time float uniform Current shutter time as specified by RiShutter dtime float uniform The amount of time covered by this shading sample dPdtime vector varying How the surface position P is changing per unit time as de scribed by motionblur in the scene Output P point varying Displaced surface position N normal varying Displaced surface shading normal Table 6 8 Predefined Displacement Shader Variables 6 2 5 Predefined Imager Shader Variables Name Type Storage Description P point varying Pixel raster position Ci color varying Pixel color Oi color varying Pixel opacity u v float varying Surface parameters Set to pixel s raster coordinates S t float varying Surface texture coordinate Set to pixel s raster coordinates du dv float varying Change of surface parameters du 1 0 x resolution dv 1 0f y resolution alpha float uniform Fractional pixel coverage ncomps float uniform Number of color components time float uniform Shutter open time dtime float uniform The amount of time the shutter was open Output Ci color varyin
247. ion and reduced scattering coefficients for the subsurface sim ulation These two parameters should always be specified in pairs subsurface marble reduced scattering absorption parameters Attribute subsurface color scattering 2 19 2 62 3 00 absorption 0 0021 0 0041 0 0071 subsurface color meanfreepath subsurface color reflectance Another way to specify subsurface parameters using translucency and reflectance mean free path and diffuse reflectance These two parameters should be specified in pair If reflectance is not specified it is set to the RiColor of the surface marble reduced meanfreepath diffuse reflectance Attribute subsurface meanfreepath 8 50 5 566 3 951 reflectance 0 83 0 79 0 75 refractionindex This attribute specifies the third parameter of the subsurface simulation It is a single float indicating the relative index of refraction of the simulated material commonly referred to as n subsurface subsurface scale 1 The values for subsurface scattering use a millimeter scale Since most scenes are modeled on a different scale this attribute compensates for that instead of adjusting the parameters themselves It is a single float which defaults to 1 0 subsurface shadingrate 1 This attribute controls how many irradiance samples should be taken during the pre computation phase It is a single float which defaults to 1 0 and has
248. ion is some textual information or a meta data indexed with a key the annotation key Annotations were primarily designed for better integration with software that need to build user friendly graphical interfaces and let the user modify shader s parameters gracefully Such software usually need informations about ranges of each parameter in the shader as well as some description about how to present them to the user A classical example is to present a toggle to the user when some shader parameters represent an on off state Annotations are specified in the shader source with a pragma instruction formatted as such pragma annotation lt key gt lt text gt Where lt key gt is the annotation key and lt text gt the annotation itself The preprocessor also supports C99 s _Pragma operator _Pragma annotation lt key gt lt text gt The advantage of this is that it can be used anywhere inside a macro to emit pragma directives To perform substitution of macro parameters inside the pragma a more advanced construct is required because substitution does not happen inside strings define MAKE_STR2 str str define MAKE STR str MAKE STR2 str define MAKE PRAGMA keysuffix textdata _Pragma MAKE STR annotation MAKE_STR key keysuffix MAKE_STR annotation text with textdata MAKE_PRAGMA special a macro parameter When run through the preprocessor this results in pragma annotati
249. ions to print messages using 3Delight s error handler The RiMutex class A cross platform locking mechanism is provided through this class void RiMutex Lock void RiMutex Unlock Locks or unlocks this object 10 2 7 The VolumeTracer API This API provides functions to trace rays in a voxel grid as suitable for volume rendering It is available through a RSL plug in so it is callable from inside regular RenderMan shaders In summary the VolumeTracer API allows a shader to Chapter 10 Developer s Corner 241 e Manage a voxel grid The voxel grid contains a certain number of attributes at each grid vertex Those attributes are grouped into categories each categories being computed by a RSL shader e Trace a bundle of rays in the voxel grid in SIMD and retrieve the values of all defined attributes at current ray position computed using the indicated interpolation mode These provided functionalities make it easy to write efficient volume shaders without hassle 10 2 7 1 Working Principles To use the library one has to write at least two RenderMan shaders 1 A classical ray marching volume shader that uses the provided calls to trace rays in SIMD through 3D space 2 A small shader that returns the volume attributes there can be many at any position in the volume In practice this shader will be called to query volume quantities at each grid vertex Most commonly this shader would return the density of the vol
250. ire file In order to lower memory usage for such large files it is suggested that a lower rows per strip count be used Typically 16 or 32 scanlines is a good choice tdlmake prints a warning if it encounters a file that has the aforementioned problem tdlmake warning reading texture earth tif may take a large tdlmake amount of memory Please refer to user s manual if you are tdlmake unable to convert this file Examples Here are some examples using tdlmake on the command line To create a texture named grid tdl from a TIFF named grid tif using a gaussian downsam pling filter of width 4 tdlmake filter gaussian filterwidth 4 grid tif grid tdl 10 Compression is performed on strips in TIFFs not scanlines Chapter 3 Using 3Delight 21 To create a cubic environment map in which all cube sides were rendered using 90 degrees field of view 4 tdlmake fov 90 envcube ini tif in2 tif in3 tif in4 tif in5 tif in6 tif envmap tdl or won t work in a DOS shell tdlmake fov 90 envcube in tif envmap tdl To create a texture using the high quality downsampling mode and show progress while doing SO tdlmake progress quality high grid tif grid tdl To create a shadow map from a zfile Section 8 6 dspyzfile page 170 4 tdlmake shadow data z shadowmap tdl 3 4 Using dsm2tif to Visualize DSMs dsm2tif is a utility to convert 3Delight s proprietary deep shadow map files into viewable TIFF files A DSM co
251. is associated with a key and is accessible across plug in boundaries when retrieved with the same key Such a class is created through a RixContext object and can return local global or thread local data For example RixContext context RxGetRixContext RixStorate thread_storage RixStorage context gt GetRixInterface k RixThreadData 17 thread gt storage gt Set example somedata void RixStorage Get const char i_key Returns the data associated with the give key NULL is returned if there is no data attached to the given key void RixStorage Set const char i key void i_data RixCleanupFunction i_clean NULL Sets the data associated with the given key If the key has associated data it will be cleared and it associated cleanup function will be called if provided with the previous Set function void RixStorage Lock void RixStorage Unlock Lock or unlocks this object Only necessary when accessing global storage The RixThreadUtils class This class provides access to thread related methods As of now only one method is accessible to provide a mutex object RiMutex RixThreadUtils NewMutex const Returns a RiMutex object Mutexes are necessary to serialize concurrent access to globally memory Please refer to The RiMutex class page 240 for more information All mutex objects allocated using this method must be de allocated using the delete operator The RixMessage class Provides funct
252. is important to set these options before the RiWorldBegin RiWorldEnd block since it is a RenderMan assumption that rendering may begin any time after RiWorldBegin all options must be fixed by then Also and contrary to transforms the order in which options appear is not important The RenderMan API declares a standard set of options which are used to control camera and image parameters and opens a door to implementation specific options through the RiOption call SDelight supports all of the standard options and has some specific calls both groups are described in the following sections For added flexibility many default option values are re definable through a special initialization file as described in Section 5 5 configuration file page 59 5 1 1 Image and Camera Options All the standard options are supported and are listed in Table 5 2 along with their default values Some of those options have an extended behavior in 3Delight RiDisplay Since the renderer uses floating point numbers internally the colors are exposed and quantized using the values specified with the RiExposure and RiQuantize calls How ever one may want to expose and quantize colors differently for each RiDisplay This is made possible by specifying exposure quantization and dithering values directly to RiDisplay Other settings can also be overridden for each display see Table 5 1 for the full list An extended RiDisplay command would look like variable
253. is is possible when the underlying model has a suitable parametrisation which is often the case since one needs a proper parametrisation to use texture mapping The following example code saves the ambient occlusion into a 2D texture map using the bake shadeop see bake shadeop page 110 float occ occlusion P N if is baking 1 0 1 Bake occlusion into a file bake occ bake s t occ Listing 7 8 Occlusion baking using the bake shadeop The created bake is a collection of 2D points and their associated data and is not suitable for later texture lookups To convert it into a mip mapped texture that can be read back using the texture O shadeop one could use tdlmake see Section 3 3 Using the texture optimizer page 15 tdlmake bakeres 2048 occ bake occ tdl Another way to achieve the same effect is to call RiMakeTexture from inside the RIB file or programmatically from inside a C program MakeTexture occ bake occ tdl clamp sinc 8 8 int bakeres 2048 clamp An example of the entire process is illustrated in the setup found in the DELIGHT examples baking directory 7 6 2 3D Baking When no suitable and continuous two dimensional parametrisation exists for some piece of geometry 2D baking becomes tedious or non feasible One parametrisation that is always available is the 3D space in which primitives are defined this gives us the option to save the data in a 3D point cloud file us
254. is means that to modify a member variable in a target co shader one has to use a setter method 6 1 2 7 The Void Type This type is only used as a return type for a shading language function as explained in Section 6 1 7 4 Functions page 82 Chapter 6 The Shading Language 69 6 1 3 Structures 6 1 3 1 Definition Structures or structs in short are defined in a manner very similar to the C language The main difference is that each structure member must have a default initializer struct LightDescription point from 0 0 0 vector dir 0 0 1 varying float intensity 1 Some observations e Note that there is no semicolon at the closing bracket as it is usual in C e A structure has no class modifier so each member has to be declared with the appropriate uniform or varying keyword If there is no variable class specifier uniform is assumed e Embedded structures do no need initializers since each structure will have its own member initialization e Structures can be declared anywhere in the file More generally a structure can be declared anywhere a function can be delcared and same scoping rules apply 6 1 3 2 Declaration and Member Selection Defining a structure variable is done as with standard language variables and structure members are accessed using the arrow gt operator as with C pointers Using the LightDescription structure declared in Section 6 1 3 1 Structure Definition page 69 o
255. isplay channel will not be matted by any other AOV Still certain objects might matte such an exclusive AOV if they have the RiMatte attribute switched on and output the AOV To suppress even those objects from matting an AOV 3Delight supports a matte flag for RiDisplay and RiDisplayChannel A totally unmatted AOV can be produced by setting matte to 0 and exclusive to 1 The second problem that arises is that certain AOVs contain geometry that requires an alpha channel different from the primary display s alpha One could of course just output another single channel AOV with the coverage information of each AOV that might need an individual alpha in compositing For your convenience 3Delight provides a shortcut for this the calculatealpha flag supported by the Display when set to 1 will add a correctly identified alpha channel to the display To complete the set of features that make a compositor s life a happier one 3Delight provides a way to produce images with unassociated alpha It is called associatealpha and has to be turned off by setting it to 0 to get unmultiplied output The AOVs that the renderer then produces are ready to be adjusted in the target compositing application with the requirement removed of dividing them by their alpha first For example in Apple s Shake this means you can skip the MDiv node behind each FileIn node that loads AOVs produced by 3Delight 7 11 Renderi
256. it a given primitive This option enables enabled by default or dis ables not advised automatic ray pruning in the ray tracer Disabling ray pruning may result in catastrophic performance if shaders are not written properly This parameter can be used to adjust the importance of the rays traced by a shadeop This eventually al lows fewer rays to be traced where their impact on the image is less As a general rule its value should be the factor which will multiply the result of the shadeop Proper use of this parameter can provide large gains of performance Table 6 10 Common optional parameters to ray tracing functions Chapter 6 The Shading Language 97 6 4 5 2 The trace Shadeop color trace point Pt vector R output float dist The trace shadeop is a general tool for collecting incoming light at point Pt on the surface In its simplest form it will collect light from direction R If the optional output parameter dist is specified it will contain the distance to the nearest intersection point or a very large number gt 1630 when no intersections are found Note that all parameters must be in current space trace accepts several optional named parameters which are explained below float samples Specifies the number of samples to use Higher sample counts will improve quality at the cost of performance float maxdist Specifies a distance after which no intersections are checked The default value is
257. it manually 3DELIGHT detected a leftover lock file probably because of an aborted render and is trying to delete it but couldn t This could be caused by restrictive file permissions and the file should be deleted manually T2025 netcache cannot create lock file lockfile For every cached and used file 3DELIGHT creates a corresponding lock file This mes sage means that no such lock file was created and 3DELIGHT will safely revert to the original non cached file A possible cause is a restrictrive permission in the network cache directory T2026 netcache file is larger than maximum cache size consider increasing cache size A file is too big for the cache It is either really big or the cache size is not big enough Cache size is adjusted through an option Option netcache int cachesize n Where n is the size of the cache T2027 netcache cannot copy file to cache 3DELIGHT was unable to transfer to file from its network location to the cache A possible cause is a restrictrive permission on the file or the network cache directory T2028 netcache lock file a has disappeared A lock file was deleted too early This is an indication that a texture file could have been removed from the cache while being read by another process T2038 file filename is not a valid TIFF C error The specified file is indeed a TIFF but it 3DELIGHT doesn t know how to handle it This could happen if data en
258. itude longitude timezone julian day time turbidity Ranges for each parameter are latitude Longitude These two coordinates specify the location of the observer in degrees timezone This is the standard time zone indicator Starting at 0 and ending at 12 Julian day Day of the year from 0 to 365 time Time of the day 6 30 PM is 18 5 4 Such as those used by Maya software 5 Such as those used by SoftImage software D Such as those used by Abobe Photoshop software T Native format of Truevision Inc Chapter 3 Using 3Delight 16 turbidity This is a measure of haziness ranging from 2 to 10 A value of 2 will give a clear day and a value of 10 will give a very hazy skylight An example command line would be tdlmake skymap 42 74 5 10 12 5 4 daylight tdl shadow Generates a shadowmap from a zfile When generating a shadowmap only the c option is functional lzw Compresses output texture using LZW algorithm This option is enabled by default since compressed textures take much less space and there is no noticeable speed penality when accessing them deflate Compresses output texture using the Deflate algorithm Has a better compression ration than LZW packbits Compresses output texture using Apple s PackBits algorithm Compression ratio is not as good as with LZW or Deflate but decompression is very fast c Does not compress output texture Separate
259. ity void 3 RtVoid RifPluginDelete RifPlugin i plugin It is recommended to have this entry point in the DSO since 3DELIGHT will use it to destroy DSOs loaded using RifLoadPlugin see below This function has been defined for Windows systems were memory allocation and deallocation cannot span multiple DLLs The Plug in will still work without this entry point but will leak memory on Windows systems Renderer s Entry Points The following functions are implemented in 3DELIGHT and are accessible from Ri plug ins RifPlugin RifLoadPlugin const char i name int i argc char argv Loads the Ri plug in specified named i name and add it at the end of the plug in chain It is necessary to call RifUnloadPlugins to free all allocated resources at the end of render RtVoid RifUnloadPlugins void Free all allocated resources and close all DSOs that have been loaded by RifLoadPlugin RtVoid RifAddPlugin RifPlugin i plugin Add a plug in at the end of the plug in chain The user is responsible of the actual loading and resource management tasks It is suggested to use RifLoadPlugin instead RtVoid RifRemovePlugin RifPlugin i plugin Removes a plug in from the plug in chain The user is responsible for releasing resources used by the plug in RifPlugin RifGetCurrentPlugin Returns the currently active plug in This function is important since there is no way for the plug in on which particular instance it is runn
260. k option above Option shutter efficiency 1 0 1 0 These two values control the shape of the shutter opening and closing for motion blur Smaller values provide a softer look Option shutter offset 0 0 The specified value will be added to all subsequent RiShutter and RiMotionBegin calls The main utility of this option is to write canonical RIB archives that always have the same motion range but are loaded from master RIBs that specify the current shutter time using this option That way an RIB archive is independent from shutter time and thus re usable in each frame no need to regenerate an archive because of shutter time change only specify the current offset in the master RIB before loading the archive Option trace specularthreshold 1 This angle specified in degrees is used to determine if ray sampling patterns are of specular or diffuse nature Patterns with an angle smaller than the value of this option are considered specular This is used by the occlusion and indirectdiffuse shadeops as well as the gather statement A value of 1 default disables this attribute completely IMPORTANT Don t use this attribute since it can affect the visibility of objects since varying the angle in the tracing functions can change ray s type and hence the selection of visibility attributes More about this attribute in visibility page 45 The safe way to override the default ray type for each ray tracing function
261. know about incoming light an example of a different usage is shown in Section 7 6 4 Baking Using Lights page 143 There are two ways to use illuminance 1 Non oriented Such a statement is meant to integrate light coming from all directions In other words integrate over the entire sphere centered at position illuminance string category point position statement 2 Oriented Such a statement will only consider light that is coming from inside the open cone formed by position axis and angle illuminance string category point position vector axis float angle statement Light Categories The optional category variable specifies a subset of lights to include or exclude This feature is commonly named Light categories As explained in Section 6 3 Predefined Shader Parameters page 89 each light source can have a special __category parameter which lights the categories to which it belongs Categories can be specified using simple expressions a series of terms separated by the or symbols logical and logical or Valid category terms are described in Table 6 4 If a category is not specified illuminance will proceed with all active light sources Chapter 6 The Shading Language 75 We Matches all lights regardless of their category name Matches lights that belong to category name name matches lights that do not belong to category name including lights that do not belong to any cat
262. kup region in both s and t expressed in units of texture coordinates range 0 1 A value of 1 0 would request that the entire texture be blurred in the result In ray tracing specifies the half angle of the blur cone in radians Specifies blur in s only Specifies blur in only Multiplies the width of the filtered area in both sand t Specifies width in s only Specifies width in t only Specifies the number of samples to use for shadow and environment lookups This influences the antialias quality A value of 16 is recommended for shadow maps and 4 is rec ommended for both DSM and environment lookups texture only uses this value with the box filter In ray tracing mode specifies the number of rays to trace If a channel is not present in the texture use this value Specifies the reconstruction filter to use when accessing the texture map Supported filters are gaussian triangle and box Used to prevent self shadowing in shadow If set to 0 the global bias is used as specified by Option shadow bias see Section 5 1 op tions page 29 texture only Returns the mipmap level used for the lookup If this is set to 1 single channel textures have their values duplicated to all channels when do ing a color lookup 0 leaves the default behavior of setting the missing channels to the value pro vided by fill If set to 1 lookups will be interpolated be tween th
263. le bool SxCallShader SxShader i shader SxParameterList i paramList Calls executes a shader i shader Shader to evaluate i paramList Parameter list to use created by SxcreateParameterList Result of the evaluation can be queried using the SxGetParameter function on i paramList The shader is run with the lights and co shaders which were created in the same Sx context Any light shader created is added to the active light list and any shader created with a non null handle name is added to the co shaders list 10 2 3 2 Example Usage 10 2 4 The Point Cloud API An easy to use C API is provided with 3Delight to read and write point cloud files as those generated by the bake3d shadeop To use the API one has to include the pointcloud h header file that is distributed in the package and link the application with the 3Delight library see Section 10 3 linking with 3delight page 244 10 2 4 1 Point Cloud API Data Types Only one type is defined in pointcloud h typedef void PtcPointCloud This typedef is used as a handle to a point cloud file on disk 10 2 4 2 Point Cloud Reading PtcPointCloud PtcSafeOpenPointCloudFile const char filename This function opens a given file for reading and returns a file handle than shall be used in other reading calls PtcPointCloud PtcOpenPointCloudFile const char filename int nvars const char vartypes const char varnames This function opens a given file for r
264. le to control the presence of outlines It is also possible to process more than one variable in the same image For example to emphasize the contour of the object in the previous example we would use Declare outline color Quantize outline 255 0 255 0 5 DisplayChannel N float edgefilterwidth 1 float edgethreshold 0 3 DisplayChannel Oi float edgefilterwidth 2 5 float edgethreshold 0 1 color edgecolor 1 0 3 0 3 Display mixed outline tif tiff outline string edgevariables N 0i Notice that this time we base most of the edge detection on normals instead of depth Which is better depends on the scene involved and the goals of the artist Finally 3Delight allows basic compositing of detected edges over any output variable For example to see what the edges would look like over the normal image DisplayChannel N float edgefilterwidth 2 float edgethreshold 0 3 color edgecolor 0 0 0 Display cheesy tif tiff rgb string edgevariables N Figure 7 6 Example of edge detection using normals The first image is a standard render The next one is the result of finding normal outlines The third image is a combination of normal outlines and opacity outlines The final image is of black outlines composited over the rgb display Chapter 7 Rendering Guidelines 153 7 12 Dicing Cameras As we already know 3Delight renders geometry by tessellating it into micro polygons This
265. le values are Izw on zw 1 aw zip deflate and off uncompressed The default is lzw int bakeres Specifies the resolution when converting a bake file int progress If set to 1 a progress indicator will be printed to the console int separateplanes If set to 1 enables the separateplanes flag of tdlmake see tdlmake options page 15 int flips If set to 1 enables the flips flag of tdlmake see tdlmake options page 15 int flipt If set to 1 enables the flipt flag of tdlmake see tdlmake options page 15 int newer If set to 1 enables the newer flag of tdlmake see tdlmake options page 15 Chapter 5 3Delight and RenderMan 59 float gamma Sets the gamma flag of tdlmake see tdlmake options page 15 float rgbagamma 4 Sets the rgbagamma flag of tdlmake see tdlmake options page 15 string colorspace Sets the colorspace flag of tdlmake see tdlmake options page 15 5 4 2 Archives 5 4 2 1 RiArchiveRecord In addition to what is required by the specification 3Delight will attempt to parse the verbatim type requests as RIB when used in immediate rendering mode This is for consistency with the results obtained when RIB commands are injected with this function in RIB output mode This will only work correctly if complete commands are output in a single RiArchiveRecord call 5 4 2 2 Inline Archives The following two commands can be used to define inline archiv
266. lect material type for surfaces using Attribute photon shadingmodel This will indicate how each surface react to photons Valid shading models are matte chrome water glass and transparent 5 Enable photon map generation for desired lights using Attribute light emitphotons on Normally only spot lights point lights and directional lights are turned on for photon generation Light sources that do global illumination work such as calling occlusion or indirectdiffuse should not cast photons In this single pass approach the total number of bounces both diffuse and specular are set using RiO0ption For example to set the total number of bounces to 5 one would write Option photon maxdiffusedepth 5 maxspeculardepth 5 Using the single appoach to photon mapping has some interesting advantages e Only uses core memory no data is written to disk if the user doesn t want it e Simple to use with already established pipelines The main drawback being that generated photon maps are not re usable 7 4 2 3 Two Pass Photon Mapping If re using photon maps is a prerequisite then the two pass approach can be used to generate the photon maps and save them into files to be used in subsequent renders This is done much like for the one pass approach but instead of using the Option photon emit command a special photon hider is used Hider photon int emit 100000 When using this
267. left and right eye are rendered at once Rendering many views at once can save a substantial amount of time The main performance gains come from 1 Scene loading is performed only once for all camera views The gains in this case are significant for large scenes 2 Shading is performed only once in the case of the REYES hider 7 8 1 Semantics Multi camera rendering is enabled by specifying a camera name previously declared by RiCamera to the RiDisplay command Follows a RIB snippet to illustrate this FrameBegin Projection perspective fov 60 TransformBegin Translate to the left Translate 3 0 0 Camera right_eye TransformEnd Display left eye tif tiff rgba Display tright_eye tif tiff rgba string camera right eye WorldBegin WorldEnd FrameEnd Listing 7 11 Example of multi camera usage 7 8 2 Limitations The main limitation of the multi camera rendering feature is the fast that shading only occurs once This makes the render faster but since the shader is invoked only once all view dependent computations such as specular highlights will be incorrect To invoque the shader once per camera it is necessary to use a special attribute Attribute shade viewdependent 1 This will fix the view dependent shading problem mentioned above but will be slower because shading is performed more often When rendering effects such as occlusion which is not view dependent this option should be set to
268. lems may arise and high resolution shadow maps are needed If objects are too close and parts of them are clipped shadows might be missed 3Delight supports the midpoint Section 5 1 options page 29 algorithm for normal shadow maps This should help to get rid of shadow bias problems in most cases 7 2 3 Deep Shadow Maps Deep shadow maps retain many of the features found in normal shadow maps and provide some more goodies e Translucent shadows Translucent surfaces cast correct shadows e Shadows in participating media It is possible to render volumetric shadows using DSMs the display driver has a flag to account for this feature see Section 8 8 dspy_dsm page 171 e Supports mipmapping DSMs are mipmapped which means that they exhibit much less aliasing artifacts than normal shadow maps e Needs lower resolution Instead of generating large shadow maps to boost quality one can generate a smaller DSM by using higher PixelSample values when creating the DSM Chapter 7 Rendering Guidelines 124 e Copes well with fine geometric details Fine details such as hair and particles can be handled without increasing the shadow maps resolution too much e Render time shadow lookups are faster Since DSMs are prefiltered render time lookups are faster in general than with normal shadow maps since the signal reconstruction step is more efficient In addition DSMs are more texture cache friendly than shadow maps e Easily included in a
269. les Listing 7 4 Ambient occlusion using a lightsource shader 7 4 2 Photon Mapping 3DELIGHT supports photon mapping for both caustics and indirect lighting Photon maps can either be generated in a different pass and stored on disk for re use or they can be automatically generated by 3DELIGHT in the main rendering pass and stored in memory only The next two sections describe the two approaches in detail Examples illustrating both methods can be found in DELIGHT examples photons 7 4 2 1 Photon Mapping Concepts Photon mapping is an elegant technique to render effects such as caustics and multi bounce global illumination efficiently The algorithm proceeds by tracing a specified number of photons from light sources that are then bounced from surface to surface and stored on diffuse surfaces The stored photons can then be used to compute light irradiance during the main beauty pass The main applications for photon maps are Render caustics To do this one needs to explicitly call a shadeop to compute irradiance either by calling photonmap see photonmap shadeop page 105 or caustic see caustic shadeop page 106 Render color bleeding using final gathering This is trivially achieved by rendering a photonmap and calling indirectdiffuse which will automatically query photon maps for secondary bounces More about final gathering in Section 7 4 3 Final Gathering page 133 and indirectdiffuse
270. lete in RI filter filter this causes a memory leak under Windows On Windows platforms RI filters should declare the RifPluginDelete function to delete a specific plugin This is needed on windows since objects should be deallocated in the DLL that did the allocation R5017 procedural object identifier exceeded its bounds by excedent The bounds supplied to the RiProcedural call were not large enough for the objects which the procedural generated upon expansion R5018 unknown or unavailable interface requested to RixContext interfaceid A shader plugin RslPlugin called GetRixInterface with an interface identifier which is either invalid or inappropriate for the current context eg k RixLocalData in an initialization function Chapter 9 Error Messages 187 R5019 string values are not allowed in 3D texture files see parameter parametername of bake3d texture3d A shader tried to bake or retrieve a string value This is often caused by a misnamed parameter R5027 failed to open bake file manager service socket errormessage This happens when using the R5031 error writing to point cloud file filename errormessage There was an error while writing to a given point cloud file The error returned by the system is included in the error message R5042 unknown camera camera Any camera provided to RiDisplay must be declared using RiCamera R5044 Invalid empty camera name specified to RiCamera R5045 Token
271. lic void light output vector L output color Cl Declaring this method makes the class usable as a valid light shader can be called by RiLightSource and RiAreaLight public void opacity output color Oi If this function is declared 3Delight will call it when evaluating transmission rays see transmission shadeop page 98 This can lead to a good performance benefit since computing opacity is usually much less expensive than evaluating the entire surface shader Table 6 1 Predefined class shader methods This shader structure allows the inclusion of both a surface and a displacement entry points Listing 6 1 demonstrates how this is done and shows the clear benefits of retaining the state of variables in shader objects In the context of traditional shaders sharing data between different methods had semantics or was resolved using ad hoc methods 1 Share the result of the computation using message passing see Section 6 4 8 Message Passing and Information page 113 This works but complicates the data flow 2 Re do the same computation in both the surface and displacement shaders Also works but time is lost in re computation 3 Displacement is performed inside the surface shader This is the most practical solution but sadly it doesn t give the renderer a chance to do some important render time optimizations Chapter 6 The Shading Language 64 class plastic_stucco float Ks 5 float Kd 5 float Ka
272. lines 166 rifargs and rifend parameters to handle plug in filters If we want to run our example filter on a simple RIB 4 renderdl rif example so Translate 0 0 10 WorldBegin Sphere 1 1 1 360 Sphere 0 5 0 5 0 5 360 WorldEnd D This is a CTRL D Total RiSphere area 15 707964 Passing arguments to Ri plug ins is straightforward using the rifargs and rifend parameters renderdl rif somerif so rifargs argi arg2 arg3 rifend somerib rib This example will load somerif so and pass three arguments to the RifPluginManufacture function Chaining multiple Ri plug ins on the command line is accomplished by using the rif option many times renderdl rif somerif so rigargs s rifend rif anotherrif so rigargs p rifend In this case two filters will be loaded and executed in sequence the first one somerif so will receive s as an option and the second one will receive p It is sometimes useful to run a RIB through one or more filters and store the filtered RIB back on disk This is accomplished using the catrib command line option As an example lets modify the myRiSphereV function defined in Listing 7 17 so that it outputs RiDisks instead of spheres RtVoid Example myRiSphereV RtFloat radius RtFloat zmin RtFloat zmax RtFloat tmax RtInt n RtToken tokens RtPointer params 1 Example current plugin Example RifGetCurrentPlugin current plugin m area 4 0f M PI radius ra
273. lls 3Delight to render polygon meshes with smooth normals instead of geometric normals It will have no effect if the N primitive variable was already supplied with the mesh shade shadingrate 1 This is exactly equivalent to the ShadingRate command shade relativeshadingrate 1 shade resetrelativeshadingrate 1 relativeshadingrate sets the value of the relative shading rate This will be multiplied by all the relative shading rates found upward in the attribute stack resetrelative shadingrate will reset the current value of the relative shading rate to the provide value meaning that relative shading rates won t be considered from that point up wards Final shading rate of the surface is computed by multiplying the shading rate by the cumulated relative shading rates The following example illustrates how this feature works ShadingRate 2 0 AttributeBegin Attribute shade relativeshadingrate 10 0 shading rate is now 20 AttributeBegin Attribute shader relativeshadingrate 0 2 shading rate is is now 4 AttributeBegin Attribute shader resetrelativeshadingrate 0 1 shading rate is now 0 2 since 0 1 x 2 0 2 AttributeEnd AttributeEnd AttributeEnd 3 Calls to the procedural will then be serialized Chapter 5 3Delight and RenderMan 54 5 3 Geometric Primitives 3Delight supports the entire set of geometric primitives defined by the RenderMan standard Since the primitives are explained in gre
274. ls expansion When procedurals expansion is enabled the output is a flat RIB including the content of all accessed archives read through ReadArchive and procedurals called by RiProcedural The actual options are better illustrated through an example This one must be called before RiBegin or it will have no effect With this option the output stream will be gzipped RtString compression 1 gzip RiOption rib compression RtPointer compression RI NULL RiBegin test rib Set output format to binary RtString format 1 binary RiOption rib format RtPointer format RI NULL Enable procedurals expansion during output RtString expansion 1 on RiOption rib callprocedurals RtPointer expansion RI NULL Scene description follows here RiEnd Listing 7 13 RIB output using RiBegin Some important remarks about procedurals expansion It is disabled by default so all standard procedural calls such as RiProcDynamicLoad are replaced by their RIB counterpart e g Procedural DelayedReadArchive User defined procedurals are always expanded When calling a procedural such as RiProcDynamicLoad the level of detail is set to RI INFINITY Contrary to normal rendering RIB output does not perform any kind of frustum culling or visibility checks this means that procedurals are opened as soon as they are issued This ensures that the entire scene is
275. mList const char name int result_count float result int parameters_count const UserParameter parameters PtDspyError DspyFindMatrixInParamList const char name float result int parameters count const UserParameter pthe arameters All these functions search a parameter of a specific type and size in the provided parameters list as specified by DspyImageOpen refer to DspyImageOpen page 195 If the desired parameter is found and the type matches these functions will fill result with the found values and return PkDspyErrorNone So for example to find a float gamma 3 parameter one could issue float display gamma 3 float array size PtDspyError result DspyFindFloatInParamList gamma amp array size amp display gamme the ouputs paramCount parameters if result PkDspyErrorNone 1 can read array size floats in display_gamme Notes e Colors points normals and vectors are considered as arrays of floats e Integers are converted to floating points e Both user provided parameters and standard parameters see Table 10 1 are accesible with these functions PtDspyError DspyReorderFormatting int format_count PtDspyDevFormat format int out_format_count const PtDspyDevFormat out_format Reorders the format array in a specific order Parameters Chapter 10 Developer s Corner 199 void void format_count format This is the format channels description as provide
276. mage is off default YPOSITION The y cropping position in pixels only active when crop ping and fullimage is off default WHITEPOINT White point when using LOGLUV compression PIXAR_IMAGEFULLWIDTH Set when an image has been cropped out of a larger image reflects the width of the original non cropped image PIXAR_IMAGEFULLLENGTH Set when an image has been cropped out of a larger image reflects the height of the original non cropped image PIXAR_TEXTUREFORMAT Set to Image PIXAR_MATRIX_WORLDTOSCREEN World to Normalized Device Coordinates transformation matrix PIXAR_MATRIX_WORLDTOCAMERA World to Camera transformation matrix Table 8 1 Tags written by the TIFF display driver 8 4 The texture display driver This display driver writes a texture file which is readily usable by the texture shadeop It accepts the mode smode and tmode string parameters to set the wrap mode of the texture file to either black the default clamp or periodic An example usage would be Display file tdl texture rgba string mode black Note This display driver operates by first writing a normal TIFF file and then running tdlmake This means that tdlmake should be accessible 8 5 The IFF display driver This display driver writes a IFF file that is suitable for the Maya software RGB and RGBA formats are supported in 8 bits The only supported parameter is fullimage which is documented in Section 8 3
277. may cause sampling artifacts commonly known as ghosting when objects are out of focus and moving Setting this parameter to 1 will use an alternate algorithm which produces higher quality for this particular case This algorithm is slower so it should be used only if necessary Values of 2 or greater allow for a speed vs quality tradeoff with larger values increasing quality Figure 5 1 An out of focus moving disk rendered with extrememotiondof set to 0 top and 1 bottom Hider hidden depthfilter filter name Sets a filter type for depth values filtering The filter name may be one of the following min The renderer takes the minimum z value of all the sub sam ples in a given pixel max The renderer takes the maximum z value of all the sub sam ples in a given pixel average The renderer averages all sub samples z values in a given pixel Chapter 5 3Delight and RenderMan 33 midpoint For each sub sample in a pixel the renderer takes the aver age z value of the two closest surfaces or as dictated by the midpointratio hider paramter Depth associated with the pixel is then computed using a min filter of these aver ages Note that midpoint filtering may slow down renders slightly Hider hidden int maxvpdepth 1 Sets a limit on the number of visible points for each sub samples This means that no more than maxvpdepth surfaces will be composited in the hider or included in deep s
278. me print_error texture_name return red D assuming u amp v are in the range 0 1 si new u mod u 1 num tiles x num tiles x new v mod v 1 num tiles y num tiles y return texture texture name new u new v Listing 6 5 An example illustrating the syntax of a RSL function Some noteworthy points about the example above e Functions can have multiple exit points e Functions can return no value by using the void keyword e Functions can return their values using one or more output parameters e Similarly to the Pascal programming language functions can be declared inside other functions or in any new scope One particularly useful concept in the RenderMan shading language is that functions are poly morphic meaning that the same function can be delcared with different signatures to accept different parameter types For example float a plus b float a b return atb color a plus b color a b return atb 13 More formally the RenderMan shading languages imeplemtns ad hoc polymorphism through method overrides Chapter 6 The Shading Language 84 6 1 7 5 Methods Methods are declared as normal functions with the following differences They are declared inside a shader object see Section 6 1 1 2 Shader Objects page 62 They are preceded by the public keyword e Methods are not inlined as usual functions and are callable from other shaders Methods cannot be declared i
279. med using the shader variable type see Section 6 1 2 6 Co shaders page 68 2 Member variables can retain shader state This avoids ad hoc message passing and other tricks widespread in traditional shaders 3 Access to co shaders encourages a modular layer based development of looks For example illumination models can be passed as co shaders to surface shaders which can take care of the general structure 4 The separation of displacement surface and opacity methods see below provides the render with greater opportunities to optimize renderings 5 Last but not least shader objects provide a greater flexibility overall and promising future development perspectives Variables and method declarations have the usual form of traditional shaders but can be prefixed by the public keyword So how does such a class shader define its function surface displacement etc By implementing predefined methods as shown in Table 6 1 public void surface output color Ci Oi Declaring this method makes the class usable as a valid surface shader can be called by RiSurace public void displacement output point P output normal N Declaring this method makes the class usable as a valid displacement shader can be called by RiDisplacement public void volume output color Ci Oi Declaring this method makes the class usable as a valid volume shader can be called by RiInterior and RiAtmopshere pub
280. mmas to use in selecting the detail level to render The cameras should be declared using RiCamera If this is not specified the dice reference cameras are used instead If those are not specified the main camera is used dice referencecamera Selects a camera or a list of cameras separated by commas to use for dicing The camera should be declared using RiCamera as explained in Section 7 12 Dicing Cam eras page 153 derivatives integer centered 1 Centered derivatives help remove artifacts due to abutting patches having a differ ent parametric orientation They are automatically turned on with smooth shading interpolation and should never be turned off derivatives integer forcesecond 1 By default 3Delight attempts to provide shaders with values which allow second deriva tives to be computed even for very fine geometry This means for example that the derivative of the surface normal will usually not be null It also improves shading of curved surfaces When the geometry is really too detailed this may be unnecessary and have a significant impact on rendering times Setting this attribute to 0 can then improve performance without a visible degradation of the image derivatives integer smooth 1 Smooth derivatives help reduce shading artifacts at grid boundaries by providing a smooth variation of du and dv across the grid They do so by computing ideal values as if the ShadingRate attribute had been exactly met
281. mpilation process These are specified before the input file name shaderdl options shader files or directories There is no need to specify an output file name to shaderdl since it is automatically set to the name of the shader followed by the suffix sd1 The SHADERDL_OPTIONS environment variable is read for any option before reading those on the command line The v and h options do not work if set in the variable Valid command line options are o lt directory gt Specifies the output file and possibly the destination directory for compiled shaders If the specified file doesn t have the sd1 extension it is not recognized by the renderer d lt directory gt Specifies the destination directory for compiled shaders The default is the current working directory 2 As specified by the HOME environment variable 5 The identifier following the keyword surface displacement light volume or imager in the SL code Chapter 3 Using 3Delight 12 dso Generates object code shaders To use this option you must have a C compiler installed The compilation script included with 3Delight is configured to work with CC on IRIX with g on Linux and with Visual C on Windows If you have a different compiler installed you have to set an environment variable or use the compiler option For more information use the help compiler option compiler compiler This enables you to override the default C compiler used by ds
282. mples traces 16 rays for better anti aliasing color ref trace P R samples 16 occlusion indirectdiffuse Traces the number of rays specified using the following attribute see Section 5 2 3 Global Illumination Attributes page 47 Increasing RiPixelSamples only affects the anti aliasing in the primary REYES render Chapter 7 Rendering Guidelines 130 Attribute irradiance integer nsamples n The default is 64 samples If the optional float samples parameter is specified to the shadeop it overrides the nsamples attributes see occlusion shadeop page 99 gather Traces the number of rays specified to the function Automatic shadows Traces the number of rays as specified by the following attribute Attribute light integer samples n The default value is 1 SDelight automatically computes ray differentials on every traced ray this means that first order derivatives are available in shaders called in a ray tracing context This ensures that derivative functions such as Du DvO and DerivO see Section 6 4 1 math shadeops page 89 behave properly even after many reflections and refractions 7 3 7 The Ray Tracing Hider 3DELIGHT uses an efficient REYES algorithm to render objects visible from the eye and uses a ray tracer for effects such as reflections and refractions By selecting the raytrace hider however 3DELIGHT can use its ray tracer to render primary visibility The following example
283. mpliant renderer implemented a REYES algorithm a type of algorithm well suited for such grouped execution An inherent benefit of an SIMD execution pipeline is that the cost of interpretation is amortized one instruction interpretation is followed by an execution on many samples this makes interpretation in RSL almost as efficient as compiled shaders 6 1 5 1 Uniform Variables Uniform variables are declared by adding the uniform keyword in front of a variable declaration For example uniform float i Defines a uniform scalar i Uniform variables are constant across the entire evaluation sample set In slightly more practical terms a uniform variables is initialized once per grid All variables that do not vary across the surface are good uniform candidates a good example is a for loop counter It is important to declare such variables as uniforms since this can accelerate shader execution and lower memory usage NOTE The evaluation sample set is a grid in the primary REYES render but is not necessary a grid in the ray tracer 6 1 5 2 Varying Variables Varying variables are variables that can change across the surface and is initialized once per micro polygon A perfect example is the u and v predefined shader variables see Section 6 2 Predefined Shader Variables page 84 or the result of the texture call see texture shadeop page 107 To declare a varying variable one has to use the varying keyword varying color t Decl
284. n can take the same values as in the p option The way 3Delight cuts the image is controlled using the tiling option Note that each process will run with a single thread unless explicitly requested otherwise on the command line hosts hosti hosti hostn tiling ssh Specifies a list of machines to use for rendering It is also possible to specify a file instead of a host name that contains a list of machines to use The format of the file is very simple one machine name per line This option is not yet functional on Windows platforms Specifies the tiling mode to use when splitting an image for multiprocess rendering Four tiling modes are supported bi For balanced tiling default Uses feedback from the previous multipro cess render to improve the split m For mixed tiling Splits the image into almost identical squares ER For vertical tiling Splits the image into vertical stripes H For horizontal tiling Splits the image into horizontal stripes Use ssh instead of rsh to start remote renders More about network rendering in Section 7 1 Multithreading and Multiprocessing page 120 jobscript script Use script to start remote renders The script receives the command to run as its first argument and is responsible for choosing a machine and executing the command there in a proper environment jobscriptparam param When used with jobscript renderdl will pass param as the first argument of the s
285. n Mapping page 131 P2379 no caustic or global photon maps declared photon mapping will have no effect At least one global or caustic photon map should be declared in order to use photon mapping Here is an example on how to do that Attribute photon globalmap global ph Attribute photon causticmap caustic ph More about photon mapping in Section 7 4 2 Photon Mapping page 131 R0500 unsupported transmission mode mode will use 0s The specified transmission mode is not supported the default mode will be used R0501 texture texturename is of an unsupported file format The file format is not supported directly It should be converted using tdlmake first See Section 3 3 Using the texture optimizer page 15 R0502 cannot output string variable varname because it is of type type Outputting string variables is not supported by 3DELIGHT R0504 ricall is not implemented yet ricall API entry is not supported yet Chapter 9 Error Messages 185 R0505 normals of class normalclass are not supported for ricall The renderer does not accept normals of class normalclass for RiCurves and RiNuCurves primitives R0513 motion blur of attribute is not implemented 3DELIGHT doesn t support motion blur for attributes An example would be MotionBegin O 1 Color 1 0 0 Color 0 10 MotionEnd R0516 RiSubdivisionMesh unsupported subdivision scheme scheme Only catmull clark subdivision surfaces a
286. n AOV explicitly is treated as implicitly rendering black to it Thus if you had say a furry creature and you wanted to render a diffuse pass for the creature s skin and its fur each respectively the skin geometry would correctly occlude the fur on the back of the creature and the fur geometry would correctly occlude any skin of which it was in front of When you add those two AOVs together in a compositing package not using any alpha channel at this stage yet you get the exact same image as if you had rendered them into one image 5 In other renderers that have added this functionality only in recent years this is most commonly referred to as rendering in passes Chapter 7 Rendering Guidelines 150 Commonly one stage in compositing is all about adjusting black and white points gain gamma and color correction of image data In the described example this might give edge issues with geometry like fur Particularly with many AOVs that make up a single element this requires a lot of precautions and even then artifacts will often show up think of several specular diffuse and translucency AOVs making up the fur with each element requiring individual adjustments in the compositing package To circumvent this problem altogether one can ask 3Delight not to matte certain AOVs This is done with the exclusive flag see Table 5 1 This flag is accepted by the RiDisplay and RiDisplayChannel calls When set to 1 the respective d
287. n coordinates which means that all values are between 0 0 and 1 0 inclusively This command line option overrides any RiCropWindow command present in the RIB file noinit Doesn t read the renderdl file See the renderdl file page 10 stats 1 3 This is equivalent to adding the following line in the RIB file n being a number between 1 and 3 Option statistics endofframe n The higher the level the more statistics you get at a slight performance cost The default statistics level is 3 Note that there is no space between stats and the number statsfile file Prints statistics in file instead of stdout Has the same effect as putting the following line in the RIB file Option statistics endofframe 3 filename file This option may be combined with the stat in order to reduce the statistic level progress Prints a progress status after each bucket May also be enabled from the RIB file See progress option page 40 catrib Doesn t render the specified file s only outputs the RIB to stdout More about RIB output in Section 7 15 Outputting RIB page 156 o file Output the RIB to the specified file instead of stdout stdout and stderr are two special file names which output to standard output and error respectively Only meaningful with catrib 1 The aspect ratio is set to 1 0 Chapter 3 Using 3Delight 10 binary Output RIB in binary format Only meaningful with catrib gzip Compr
288. n the list in the same subsample struct PtDspyFragment s next PtDspyFragment Listing 10 3 PtDspyFragment structure Follows some important remarks about fragment lists 1 The lists are sorted in Z Furthest fragments come first in the least 2 Lists are truncated at first opaque object unless special culling attributes are set to disable hidden surface removal see culling attributes page 46 In general lists longer than one will contain fragments that are not opaque 3 The length of each list is not constant per sample of course In order to obtain the final color for a pixel the user must composite the fragments and then filter them 10 1 1 4 A Complete Example Copyright c The 3Delight Team All Rights Reserved LIBRARY 3delight AUTHOR S Aghiles Kheffache VERSION Revision DATE RELEASED Date RCSID Chapter 10 Developer s Corner Id include lt ndspy h gt include lt uparam h gt include lt ri h gt include lt assert h gt include lt stdio h gt include lt float h gt include lt string h gt include lt limits h gt ZFile Display Driver Implementation const unsigned kDefaultZFileSize 512 static void stderr_error int type int severity char msg just ignore type and severity fprintf stderr As msg h zfile format zFile format is matrices and image are r
289. name name printf light name s n name F The list of recognized uniform attributes is are listed in Table 6 20 Ri ShadingRate Ri Sides Ri Color Ri Opacity Ri Matte Ri DetailRange Ri TextureCoordinates Ri Orientation GeometricApproximation motionfactor displacementbound sphere displacementbound coordinatesystem shaderdisplacementbound sphere shaderdisplacementbound coordinatesystem geometry backfacing geometry frontfacing geometry geometricnormal grouping membership identifier name trace bias trace displacements trace maxspeculardepth trace maxdiffusedepth photon shadingmodel photon causticmap photon globalmap photon estimator sides doubleshaded visibility camera visibility diffuse visibility specular visibility trace visibility transmission visibility photon dice hair dice rasterorient cull backfacing cull hidden derivatives smooth derivatives centered subsurface groupname subsurface scale subsurface refractionindex subsurface shadingrate subsurface absorption subsurface scattering subsurface meanfreepath subsurface reflectance attribute light samples attribute light samplingstrategy attribute light emitphotons irradiance shadingrate irradiance nsamples hider composite user attributename able 6 20 attribute field names The type of each attribute is directly related to its declaration when declating t
290. ncy of shading for interior shaders It also applies to atmosphere shaders if the standardatmosphere option is set to 0 Its meaning is similar to the ShadingRate attribute it represents the area in pixels of a shading element for volumes Chapter 5 3Delight and RenderMan 36 RiO0ption render stopcallback amp function_ptr RI NULL This option only available through a direct RiOption call accepts a pointer to a function which will be called at each rendered bucket or more often to allow user code to stop the render The function prototype and option call are as follows int StopRender void data RtPointer callback RtPointer amp StopRender RiOption render stopcallback amp callback RI_NULL Returning a value of 0 will let the render continue while a value of 1 will stop it The function may be called from a different thread than the one which started the render Some care should be taken to make the function execute quickly eg avoid calling into a UI toolkit It should ideally simply test a flag which the application will set when it wants the render to abort stopper function is an alias to stopcallback for backward compatibility It is also possible to use this callback to pause a render by delaying the return from the function RiOption render stopcallbackdata amp data RI NULL This option allows specification of the data parameter passed to the callback set with the stopcallbac
291. nd avoid ray tracing effectively achieving the so called final gathering algorithm 7 4 4 Image Based Lighting Integrating synthetic elements into real footage became an important aspect of modern computer imagery To make the integration of such elements as realistic as possible it is of prime importance to respect the lighting characteristics of the real environment when rendering the synthetic elements Lighting characteristics include both the color of the elements as well as the shadows cast by those elements into the real world Both imperatives can be achieved by placing lights in the virtual environment that mimic the placement of lights in the real environment This is usually a tedious task that is also error prone A more elegant technique relies on photographs of real environments to compute lighting on synthetic elements T hose photographs are usually high dynamic range images taken on set Preparing HDR Images High dynamic ranges images come mostly in two format light probes or two fisheye images tdlmake can read both formats and convert them into a cubic environment map usable from shaders The following example converts a twofish environment in EXR format into a cubic environment map usable in 3DELIGHT 4 tdlmake twofish north exr south exr env tdl Once the environment is converted into a cubic environment map it can easily be accessed from the shading language Using HDR Images Most people are familiar with
292. nd describes light opacity It is almost never used and has been deprecated in the context of shader objects see Section 6 1 1 2 Shader Objects page 62 Listing Listing 6 2 shows how to write a standard point light Note that the position given to illuminate is the origin of the shader space see Table 6 3 and not some parameter passed to the 8 Lights are listed in the same order as issued during scene description Chapter 6 The Shading Language 77 light this is desirable since the point light can be placed anywhere in the scene using RiTranslate or similar instead of specifying a parameter light pointlight float intensity 1 color lightcolor 1 illuminate point shader 0 d Cl intensity lightcolor L L J d Listing 6 2 An example of a standard point light The solar Construct This construct is similar to illuminate but describes light cast by distant light sources It also has two forms albeit only one is partially supported by 3Delight 1 Non directional This form decribes light coming from all points at infinity such as a light dome solar statement Correctly implementing the solar constructs implies integration over all light direction inside shadeops such as specular and diffuse This is not yet implemented in 3Delight and the statement above is replaced by solar I O statement 2 Directional Describes light coming from a particular direction and covering some
293. nding irradiance attribute see Section 5 2 3 Global Illumination Attributes page 47 maxerror uniform Controls the maximum error for this specific shadeop and overrides float the corresponding irradiance attribute see Section 5 2 3 Global Illumination Attributes page 47 Table 6 12 Parameters controlling point based occlusion and color bleeding float gather string category point P vector dir float angle float samples statement else statement gather is considered as a language construct and is detailed in The Gather Construct page 7T Chapter 6 The Shading Language 104 color subsurface point Pt Returns subsurface lighting at the given point Pt Subsurface light transport is automatically computed in a separate pass More about subsurface scattering in Section 7 4 5 Subsurface Scattering page 136 Chapter 6 The Shading Language 105 Name Description uniform string groupname Allows lookups of arbitrary subsurface groups in the scene uniform string filename Specifies the name of the point cloud file to use This tells the renderer to operate in point cloud mode Refer to uniform string filenames uniform string coordsystem color scattering color absorption color diffusemeanfreepath color albedo float ior float unitlength uniform float smooth uniform float followtopology uniform string areachannel uniform string radiancechannel
294. ne can write LightDescription light_description light_description gt intensity 10 Note that the arrow operator to select structure members is a no cost operation compared to the same operator used to access co shader variables see Section 6 1 2 6 Co shaders page 68 It is possible at declaration time to override the members of a structure using a constructor LightDescription light_description LightDescription from point 1 0 0 dir vector 1 1 1 Note that the constructor runs at compile time so the member names must be constant strings Declaring arrays of structures is also trivial LightDescription light_descriptions 10 LightDescription intensity 5 6 1 3 3 Structures as Function Parameters Structures are passed to function per reference no data is copied when calling the function To modify any member of the structure inside the function it is necessary to use the output keyword For example void TransformLight output LightDescription ld matrix trs ld gt from transform trs ld from ld gt dir transform trs ld gt dir 6 1 3 4 Limitations Currently the following features are not supported Chapter 6 The Shading Language 70 e Structure inheritance and structure member functions e Passing structures to RSL plug ins e Functions cannot return structures 6 1 4 Arrays 6 1 4 1 Static Arrays Any shading language type can be used to declare a one dimensional arr
295. ne tool see Section 3 6 Using shaderinfo page 23 It is also possible to manually interrogate shaders by using a number of calls implemented in lib3delight The interrogating application should include s1o h found in DELIGHT include and link with lib3delight see Section 10 3 linking with 3delight page 244 Here is the complete list for shader interrogation calls void Blo SetPath char i path Set the paths where the library looks for shaders It accepts a colon separated list of paths Refer to Search Paths page 39 for more information on search paths which also applies to this function int Slo SetShader char i name Find and open the shader named i name Close any shader that was previously opened by S1o SetShader Returns 0 when the shader was successfully loaded char Slo_GetName void Returns the name of the currently opened shader SLO TYPE S10 GetType void Return the type of the currently opened shader See the file s1o h for details about SLO TYPE int Slo_GetNArgs void Return the number of parameters accepted by this shader SLO_VISSYMDEF 10 GetArgById int i Return information about the i th parameter of the shader The first parameter has an id of 1 See slo h for details about SLO_VISSYMDEF structure SLO_VISSYMDEF Glo GetArgByName char i name Return information about the parameter named i name See the file slo h for details about SLO_VISSYMDEF SLO_VISSYMDEF Slo_GetArr
296. ng Outlines for Illustrations SDelight has advanced inking features for toon rendering and other illustration purposes This is implemented using edge detection algorithms in image space All edge detection features are controlled through parameters to the RiDisplay call Since 3Delight can output many such displays in one render it becomes possible to output different edge detection results into different files or framebuffers For example one display can output edge detection based on depth variation and another one on surface normals variation 6 If supported by the display driver T Note that this will increase the number of actual channels in the Display or DisplayChannel by one Chapter 7 Rendering Guidelines 151 Figure 7 5 Outlines on 0i opacity and z depth Note how outlines get thinner with distance Example scene available in DELIGHT examples toon Additionally it is possible to output in the same display edges detected on many variables at once such as depth normals and any other surface variable Table 7 1 contains the list of all edge detection parameters accepted by RiDisplay Parameter Default Value string edgevariables n float edgethreshold 1e30 float edgefilterwidth 2 float edgewidth 0 color edgecolor float edgefadeout 1 1 1 near far minwidth Description Comma separated list of variables to be used for edge detection Controls edge detector sensitivi
297. niform type variable value Specifies a user defined attribute User attributes can be read in the shading language using the attribute shadeop See attribute shadeop page 114 EXAMPLE Attribute user float self_illuminated 1 Note that it is also possible to declare user defined options as described in User Options page 41 5 2 7 Other Attributes Attribute sides float backfacetolerance 90 This value is the angle in degrees which specifies how much a surface must be back facing so it can be discarded before displacement shading occurs This is to account for the fact that the displacement shader may change the orientation of the surface A value of 90 causes no backface culling to take place before displacement the safe choice and the default A value of 0 causes all backfacing surfaces to be discarded before displacement Attribute sides integer doubleshaded 0 When this is set to 1 each surface is shaded twice once as usual and once with the normals reversed This allows thickness to be given to a surface with displacement or to avoid shading artifacts where a transparent surface changes orientation Chapter 5 Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute 3Delight and RenderMan 52 trimcurve string sense inside Specifies whether the interior or the exterior of a trim curve should be trimmed cut on a NURBS surfac
298. ning a string float match string pattern subject Does a string pattern match on subject Returns 1 if pattern exists anywhere within subject 0 otherwise The pattern can be any standard regex expression 6 4 8 Message Passing and Information float textureinfo string texturename fieldname output uniform type variable Returns information about a particular texture environment or shadow map fieldname specifies the name of the information as listed in Table 6 19 If fieldname is known and variable is of the correct type textureinfo returns 1 0 Otherwise 0 0 is returned EXAMPLE mapres 0 gets map resolution in x mapres 1 gets map resolution in y uniform float mapres 2 textureinfo grid tdl resolution mapres Get current to camera matrix used to create the shadow map uniform matrix Nl if textureinfo main spot tdl viewingmatrix N1 1 0 1 Additionally a special call to textureinfo is provided to test texture existence color C if textureinfo texturename exists 0 C texture texturename else C errorcolor The existence check also checks for validity so if the file exists on disk but is not a valid texture this function will return 0 An error message will only be output if the file is present but invalid 3 See man regex for details man pages available on UNIX like platforms only Chapter 6 The Shading Language 114 Fiel
299. nl leto and harkonnen one would issue the following command this will also open a framebuffer window renderdl hosts origini leto harkonnen localhost id frame1 rib Note that by default every machine will use as many threads as possible so if origin1 has two CPUs both will be used to render the part of the image that has been assigned to the machine Additionally a machine could be specified more than once this will launch that many processes on the specific machine For convenience renderdl also accepts a text file describing the list of hosts 4 renderdl hosts workers txt leto id frame1 rib This will read all the machines listed in the file workers txt each host name on a single line and use those for rendering as well as the leto machine It is not required that the current machine is part of the hosts set one could launch a single processor render on a different machine eg if the current machine is too loaded 4 renderdl hosts worker id frame1 rib Note that different machine architectures can be used to compute a single image it is possible to use both MacOS X and Linux machines to cooperate on a single image 1 The p and the hosts options should not be used together This usually means modifying the etc hosts equiv file see rsh documentation for details Chapter 7 Rendering Guidelines 122 7 1 4 Performance and Implementation Notes It is recommanded to use multithreading when rendering medi
300. not be used with shader names n f 25 return O0 Chapter 10 Developer s Corner 237 if argc 2 amp amp strcmp argv 1 v strcmp argv 1 version a const char v DlGetVersionString const char copyright DlGetCopyrightStringO fprintf stderr shaderinfo version s nf s n v copyright return 0 F if argc 1 start else if strcmp argv 1 d format e_ribout startt b else if strcmp argv 1 t 1 format e table startt else if strcmp argv 1 a format e_annotations start else if strcmp argv 1 source strcmp argv 1 source 1 format e source start b else if strcmp argv 1 methods 1 format e methods start b Add to the default path so shaders are still found in the current directory even if the default path is modified not to include Slo SetPath for i start i lt argc i int err Slo_SetShader argv i if err 0 fprintf stderr D1GetText D1Text_2260_open argv i err exitCode 1 continue Print a header indicating which shader this is Chapter 10 Developer s Corner 238 if format e_table 1 printf s n4s n Slo_GetName Slo_TypetoStr Slo_GetType else if format e_prman 1 printf n s Zs n Slo_TypetoStr Slo_GetType Slo_GetName else if format e
301. notationKeyById 231 Slo GetArgByld clesie iussa sas eode ees 230 Slo Gertkrebohame ess 230 Slo GetArrayArgElement sss 230 Slo_GetName eene 230 Slo GetNAnnotations sees 231 Slo GetNArgS or per E rr ps 230 Slo Getlype ENEE hanes ed 230 Slo SetPath 4cioessisertse 4 E BOPEDOAReS POS 230 Function Index S1o Gert hader ccc cece cece eee ee 230 Slo Stort StE ccs cscs dea sea abrir ru d EE A 231 En EE 231 SMOOCHSLED EE 90 Specular ise ee ast tege ene eons 94 Specularbrds EE 94 e RE E DEER 94 EE 91 SQUb EE 90 Step cerifzSibehen rac Red b URENERST REEL EN E 90 Subsurf ace ed SE i raip aranan dag e er d 104 S Eface s cehcsenivud eR dE SE 114 SxCallShader 2 22 nu anges a pese a oed dos 227 SxCreateContext esee cee eens 224 SxCreateParameterlist 225 SxCreateShaderiics ci cis 004 Seaneseee e ood 225 SxDeFineSpace vii vis cess cy ne ewe ses 225 SxDestroyContext 2 eee eee 224 BzDestrovbaramneterlisr 225 SxGetNumParameters cc cece eee 226 SxGetParameter 2 c iam lit noi A 226 SxGetPredefinedParameters 226 SxSetAttribu te cisnesenaugebexedooe e pu dE 224 SxSet ptiOn uizenzleseecace etn ey LS nets 224 SxSetParameterlistGridTopology 225 SxSetPredefinedParameter 225 T EE 90 259 OR 107 texture3d i o xd 9d IE Ee shot PI NS Eege ur RE DRE sya EE E es
302. nside other methods The general form for a RSL method is as follows public return_type function_name parameters list function body return return_value For example public void surface output color Ci Oi Declares the standard surface entry point in a shader object 6 2 Predefined Shader Variables For each shader some predefined variables are provided for input and output purposes Here are the lists of variables for each shader type Variables with a at the end of their description are available only inside illuminance constructs see The Illuminance Construct page 74 Chapter 6 The Shading Language 85 6 2 1 Predefined Surface Shader Variables Name Type Storage Description Cs color varying Surface color Os color varying Surface opacity P point varying Surface position dPdu vector varying Derivative of surface position along u dPdv vector varying Derivative of surface position along v N normal varying Surface shading normal Ng normal varying Surface geometric normal u V float varying Surface parameters du dv float varying Change of surface parameters sS t float varying Surface texture coordinates E point uniform Position of the eye I vector varying Incident ray direction ncomps float uniform Number of color components time float uniform Current shutter time as specified by RiShutter dtime float uniform The amount of time covered by this shading s
303. nt based functionalities 7 7 1 Difference with Occlusion Baking Firstly it is important to remember that point based occlusion and color bleeding is not occlusion baking as explained in Section 7 6 Baking page 141 point based occlusion computes the occlusion during the beauty second pass while the baking approach computes the occlusion during the first pass The baking in the point based method is nothing more than a simple conversion of scene s geometry into a point cloud file That is why we will refer to the first pass in the point based approach as the pre processing or conversion 7 7 2 Benefits Over Ray Traced Occlusion Main benefits are summarized below e Due to the nature of the point based approach the resulting ambient occlusion effect is smooth e Displacements a costly operation in the ray tracing case come at no additional cost in the point based method e No need to declare objects visible to the ray tracer this can save a lot of memory The drawbacks of point based occlusion can be summarized in the following points e It is an approximation to the real occlusion In general the obtained occlusion is darker than the ray tracing case and it is necessary to adjust quite a few parameters to obtain the same look More about parameter adjustments in Section 7 7 4 Algorithm Control Parameters page 147 e The pipeline is obviously more complicated since one need a special pass to create the po
304. ntains visibility data for any given depth in a scene so one single 2D image e g a TIFF cannot describe all the information provided by a DSM that is why command line parameters are provided to specify at which depth the evaluation occurs z depth Specifies a relative depth at which the deep shadow map is evaluated Relative means that each pixel in the image is evaluated at its own depth It is computed as follows pZmax pZmin x depth pZmin pZmin and pZmaz being the depths of the closest and the furthest features present in the pixel z 1 is the default which shows the amount of light that passes through to infinity at each pixel Zdepth Specifies an absolute depth range 0 1 to evaluate the deep shadow map Absolute means that all pixels in the output image are evaluated at the same depth computed as follows Zmaz Zmin x depth Zmin Zmin and Zmaz being the depths of the closest and the furthest features in the DSM bias n Specifies a shadow bias for deep shadow map evaluation This is needed to avoid self occlusion problems If the produced TIFF contains noisy areas consider increasing this parameter Default is 0 015 opacity By default dsm2tif assigns a visibility value to each pixel in the output TIFF specifying this option assigns opacity values to each pixel opacity 1 visibility This means that dark areas in the image indicate that light passes through unnoccluded mipm
305. nts RiFormat 640 480 1 m RiFrameAspectRatio 1 0 Square pixels RiScreenWindow 1 3333 1 3333 1 1 Default computed using RiFormat 640 480 1 333 RiCropWindow 0101 No cropping RiProjection orthographic RiClipping 0 1e30 RiPixelSamples 22 If motion blur or depth of field are used in crease these values to at least 4 4 RiPixelFilter box 2 2 A high quality setting would be sinc 6 6 RiExposure 1 0 1 0 Gain 1 Gamma 1 RiDisplay default tif tiff rgba Create a RGB TIFF named default tif Table 5 2 Standard RenderMan options and their default values Chapter 5 3Delight and RenderMan 34 5 1 2 Implementation Specific Options 3Delight uses implementation specific options only when no standard option provides the desired functionnality Even if we call them implementation specific most of the options described in the following section are commonly used and well defined in other RenderMan implementations All the supported implementation specific options are listed in Table 5 3 along with their default values Rendering Options Option shadow float biasO 0 225 Option shadow float biasi 0 3 Option shadow float bias 0 225 When using shadow maps a surface may exhibit self shadowing This problem is caused by precision errors and quantization and appears as gray spots on the surface This problem occurs when the distance of an object to a light source computed while rendering a s
306. number 1 Name _radiosity Type color Bounding box 5 71307 6 24433 3 51055 1 55966 1 02841 3 76218 World to eye matrix 1 0 0 0 0 1 0 0 0 0 1 5 0 0 0 1 World to ndc matrix 3 73205 0 0 0 0 3 73205 0 0 0 0 1 5 0 0 1 5 Format 400 400 1 3 11 Using ptcmerge ptcmerge is a simple utility to merge point cloud files see Section 7 6 Baking page 141 The general command line syntax is ptcmerge h lt in ptc gt other input files lt out ptc gt Input files can contain different data channels and in different order ptcmerge will only merge channels present in all input files Chapter 4 Integration with Third Party Software 28 4 Integration with Third Party Software 4 1 Autodesk s Maya The package comes with a full featured production ready Maya plug in Delight For Maya Please refer to 3Delight For Maya Technical Specifications For a brief discussion about plug in s features 3Delight For Maya User s Manual For a length description and rendering guidelines 4 2 Softimage s XSI We provide a separate product for XSI integration 3Delight For XSI Please contact us at info 3delight com for further information 4 3 Side Effects Software s Houdini The following Houdini integration tips work with later Houdini 9 packages Integration in Houdini is substantially improved by letting Houdini know that 3Delight is the preferred RenderMan renderer This is done by setting the HOUDINI_D
307. o Use the compiler help to see the different compilers available or how to build your own custom C compiler command help compiler Explains how to pick a C compiler using the compiler or by setting the SHADERDL_ CC COMMAND environment variable int Generates byte code shaders default embed source Adds source code into the sd1 This enables automatic recompilation when backward compatibility is broken See recompile sdl for a more complete solution recompile sdl When backward compatibility is broken providing the sd1 was compiled with the embed source option it is recompiled each time a render requires it therefore slowing down the rendering process This option makes the shader accept sd1 files recompiles them provided it contains its own source code and replaces them If a path is specified instead all sd1 in it are affected Only byte code shaders may be updated with this option O lt n gt Specifies the optimization level from 0 to 3 Refer to Optimization Levels page 13 w lt n gt Sepcifies warning level 0 Disables all warnings not recommended 1 Logs important warnings only default 2 Logs all warnings I lt directory gt Specifies a directory to search for include d files D lt symbol gt Defines a preprocessor symbol See also Predefined Macros page 13 E Stops after the preprocessing step c Stops after the shading language to C translation pass keep c
308. o save disk space Only scaling down is supported This means that s must be smaller than 1 Deep shadow maps and cube environment maps are not scaled binary If used with the package option the copied RIB files will be binary encoded Chapter 3 Using 3Delight 25 gzip If used with the package option the copied RIB files will be gzipped noshaders Causes ribdepends not to search for shaders notextures Causes ribdepends not to search for texture files nooutputs Causes ribdepends not to process the paths of output files RiDisplay RiMakeTexture etc noprocedurals Causes ribdepends not to search for DynamicLoad and RunProgram procedurals Does not affect the DelayedReadArchive procedural noinit Do not read renderdl file v Print version h Print this help The default behavior when no options are given is to list resources required for the proper rendering of the specified RIB file s or standard input when no files are specified Each dependency is prefixed by a character indicating its type t Texture or shadowmap dependency 3D textures point cloud files are also considered s Shader dependency x Procedural dependency u Unresolved dependency could not find file on filesystem o Output file such as a file specified to RiDisplay or RiMakeTexture c Conflicting dependencies that have the same name but different paths These might be renamed in the package when using the package opti
309. o a gamma of 1 0 before performing computations on it rgbagamnannnn Indicates the gamma of each red green blue and alpha channel of the input image This allows tdlmake and 3Delight to convert the texture to a gamma of 1 0 before performing computations on it colorspace lt linear srgb BT 709 gt Indicates the color space of the input image linear sRGB or BT 709 This allows tdlmake and Delight to convert the texture to a linear space before performing com putations on it byte or ubyte Forces the output to be 8 bit unsigned data sbyte Forces the output to be 8 bit signed data ushort Forces the output to be 16 bit unsigned data short or sshort Forces the output to be 16 bit signed data float Forces the output to be floating point data pixelaspectratio Specifies the aspect ratio of the pixels This can be retrieved with textureinfo see textureinfo shadeop page 113 imageaspectratio Specifies the aspect ratio of the image A pixel aspect ratio is computed from this value newer If the destination texture already exists regenerates it only if one of the input textures is newer than the destination nomipmap By default tdlmake creates mipmapped textures that are suitable for efficient and high quality texture mapping This option turns this feature off and is not recommended progress Shows texture creation progress only useful for really large textures or really slow computers y Prin
310. objectName grid center bboxCenter grid size bboxSize grid nbcells nbCells grid shader noisy noisy intensity 0 7 d Create ray float stepLength uniform string interpolation linear float rayID VolumeTracer_InitRay objectName transform object P I transform object P stepLength interpolation float progress 0 0 float attributes resize attributes nbAttributes while progress lt 1 0 float step progress VolumeTracer_StepRay rayID step attributes Use attributes The noisy s1 shader has to define a varying output array of floats as in surface noisy uniform float intensity output varying float density 3 color D noise P intensity density 0 D 0 density 1 D 1 density 2 D 2 10 3 Linking with 3Delight 244 3Delight comes with a library which implements the RenderMan API interface Here is how to link with it on different platforms IRIX CC o main main cpp I DELIGHT include L DELIGHT lib L lib i686 13delight 1m 1dl 1c Chapter 10 Developer s Corner 245 Linux g o main main cpp I DELIGHT include L DELIGHT lib L 1ib i686 13delight 1m 1dl 1c Windows cl I ADELIGHT include ADELIGHT lib 3delight lib main cpp MacOS X g o main main cpp I DELIGHT include L DELIGHT lib framework CoreFoundation lstdct 13delight 10 4 Attaching annotations to shaders An annotat
311. of this chapter deals with the ray tracing version of occlusion the point based approach is detailed in Section 7 7 Point Based Occlusion and Color Bleeding page 145 3 8 Qs and shader are also valid but slower and add very little Chapter 7 Rendering Guidelines 131 The number of samples specified as a parameter to occlusion is a quality vs speed knob less samples give fast renders and more noise more samples yield to longer render times but smoother appearance 16 to 32 samples is a recommended setting for low quality renders 128 and more samples are needed for high quality results It is important to turn RiShadingInterpolation to smooth this increases occlusion quality especially on the edges where two different surfaces meet and form a concave feature Occlusion can also be returned using the indirectdiffuse shadeop see indirectdiffuse shadeop page 99 This is useful when both indirect illumination and ambient occlusion are needed Note that using indirectdiffuse to compute occlusion can be much more costly than using occlusion since it often triggers execution of shader code Here is a simple light source shader illustrating the use of occlusion light occ light float samples 64 string category occlusion float __nonspecular 1 1 normal shading normal normalize faceforward Ns I illuminate Ps shading normal 1 Cl 1 occlusion Ps shading normal samp
312. oftware must display the following acknowledgement Chapter 12 Copyrights and Trademarks 249 This product includes software developed by the University of California Berkeley and its contributors 4 Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission THE REGEX LIBRARY IS PROVIDED BY THE REGENTS AND CONTRIBUTORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONSEQUENTIAL DAMAGES INCLUDING BUT NOT LIMITED TO PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES LOSS OF USE DATA OR PROFITS OR BUSINESS INTERRUPTION HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY WHETHER IN CONTRACT STRICT LIABILITY OR TORT INCLUDING NEGLIGENCE OR OTHERWISE ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE 3Delight uses ILM s OpenEXR library to read OpenEXR files The license requires the following to appear in the software Copyright c 2002 Industrial Light amp Magic a division of Lucas Digital Ltd LLC All rights reserved Redistribution and use in source and binary forms with or without modification are permitte
313. ointer to the standard error handler of type RtErrorHandler The display driver can use this function to print messages through 3DELIGHT s error handler as de clared by RiErrorHandler Refer to Section 10 1 1 4 display driver example page 202 3dl_quantize_info EI 5 fe Quantize information for each of the formatcount channels Tuples of 5 floats for zero one min max and dither Comes from either RiQuantize or the quantize and dither dis play parameters Table 10 1 Standard parameters passed to DspyImageOpen DspyImageData 3Delight calls this function when enough pixels are available for output Most of the time this happens after each rendered bucket However if DspyImageOpen asks for scanline data ordering a call to this function is issued when a row of buckets is rendered image Opaque data allocated in DspyImageOpen xmin xmax_plus_one ymin ymax_plus_one Screen coordinates containing provided pixels data entrysize Size in bytes of one pixel For example if eight bit RGBA data was asked entrysize is set to four data Pointer to the actual data organized in row major order DspyImageClose Called at the end of each rendered frame It is time to free all resources that were used and free image which was allocated by DspyImageOpen DspyImageDelayClose If this entry point is defined in the display driver it is called instead of DspyImageClose with the difference being that the call occurs
314. olume lazy fog 1 color Cv 0 volume s color color Ov 0 volume s opacity Main code here to compute Cv and Ov Composite the volume with the surface Ci Cv 1 Ov Ci Oi Ov 1 Ov Oi That last composition step allows the same shader to work in both modes 2 The volume shader must compute the atmospheric effect from P to P I not from P to E as is often done Also the shader must be built such that splitting the evaluation range in two at any point and compositing the result of the evaluation of both subranges yields the same values This will enable partial evaluation of the volume when it is split by transparent surfaces This condition can be ignored if no transparent surfaces are ever used This requirement means that volume marching shaders are usually best written as a compositing loop volume volumetric_smoke color Cv 0 volume s color color Ov 0 volume s opacity Main volume marching integration loop while color Ce 0 volume element color color Oe 0 volume element opacity Compute Ce and Oe here for one volume element Composite the volume element in front of the previous ones Cv Ce 1 Oe Cv Ov Oe 1 Oe Ov Composite the volume with the surface Ci Cv 1 Ov Ci Oi Ov 1 Ov Oi Option render float volumeshadingrate 1 0 This options controls the freque
315. on An example run on the example found in DELIGHT examples outputvariables gives the fol lowing output ribdepends toonStill rib s usersi aghiles software 3delight shaders ambientlight sdl s usersi aghiles software 3delight shaders pointlight sdl u matte output sdl o toonStill normals tif o toonStill points tif o toonStill tif We can see that the toonStill rib depends on two shaders and produces three output files matte output sdl is listed as undefined because it has not been compiled Note that RiDelayedReadArchive is treated like a RiReadArchive If procedurals are to be expanded instead use renderdl with the callprocedurals option as in renderdl catrib callprocedurals somefile rib ribdepends Chapter 3 Using 3Delight 26 3 9 Using ptc2brick ptc2brick converts one or more point cloud files into a single brick map The general command line syntax is ptc2brick options lt in ptc gt more input files lt out bkm gt The available options are maxdepth d Specifies a maximum depth d for the brick map tree Smaller depths will give smaller files The default maximum depth is 15 maxerror e Specifies maximum tolerated error ei in the brick map This is a trade off between accuracy and file size radiusscale s Specifies a scale s that will be applied to all points radii For s higher than 1 blurrier and smaller brick maps are created Specifying a value smaller than 1
316. on RiPointsPolygons and RiPointsGeneralPolygons All polygonal primitives support the following variable types constant uniform varying vertex and facevarying Note vertex and varying interpolation over a polygon is ill defined since it depends on how the polygon is tesselated by the renderer 5 3 5 Points Points are supported in 3Delight through the standard RenderMan RiPoints primitive Points size is controlled using either width or constantwidth variable RI WIDTH or RI CONSTANTWIDTH in the API The way 3Delight renders points is selectable during primitive declaration using the uniform string type variable which can take one of the following values particle blobby patch sphere or disk particle The default mode is to render points using a lightweight primitive suitable for clouds of tiny particles such as clouds of dust stars etc Particles are rendered as circles using a specialized algorithm which is suitable for such small primitives Note Displacement and volume shaders as well as output variables are not supported for lightweight particles blobby Renders the particles as blobbies implicit surfaces In this case the energy field radius is defined by width or constantwidth Particles created as blobbies will blend together smoothly and will also blend all primitive variables sphere disk patch Points are rendered using the RiSphere RiDisk or RiPatch
317. on keyspecial annotation text witha macro parameter There is no particular syntax for the annotation key or text fields and 3Delight will not perform any syntax checking on these it is up to the shader writer to decide the syntax depending on the software which is reading it Follows an example shader annotated with informations about its parameters author and version surface annotations float Ks 1 0 float has_shadow 0 code goes here pragma annotation author Aghiles Kheffache pragma annotation version 1 0 pragma annotation Ks comment Specular intensity pragma annotation Ks range 0 10 pragma annotation has shadow type toggle Listing 10 4 An example annotated shader 3 When two annotations share the same key their lt text gt field is concatenated Chapter 10 Developer s Corner 246 A user interface builder could then draw a toggle for the has_shadow parameter since the shader writer specifically said that it was a toggle and not a simple scalar value Annotations in a compiled shader are accessible through the shaderinfo utility Section 3 6 Using shaderinfo page 23 or through 3Delight library calls Section 10 2 5 The Slo API page 230 Here is the output of the shaderinfo a command executed on the example in Listing 10 4 shaderdl annotations sl shaderinfo a annotations surface test 5 Ks comment Specular intensity Ks rang
318. on for the render lower resolution means less used memory and faster renders PixelSamples and PixelFilter More pixel samples means slower renders A PixelSamples 6 6 is more than enough for final renders even with motion blur Using the high quality sinc filter requires a wider support PixelFilter sinc 4 4 or more that is why it is generally slower ShadingRate Test renders should specify ShadingRate 4 or more Final renders should use ShadingRate 1 Smaller shading rates are rarely needed and are often used by shaders that produce high frequencies Bucket and Grid size In our experience a bucket size of 16x16 and a grid size of 256 is a very good general setup for 3Delight This can be bettered by doing experiments on a particular scene Also a given grid should cover approximately one bucket in raster space so for a shading rate of 1 and a bucket size of 32x32 the grid size should be 1024 Horizontal or Vertical By default the renderer issues buckets row per row This is not the optimal bucket order if the image contains objects that are thin and horizontal Use Option render string bucketorder vertical to specify a vertical bucket issuing strategy column by column This trick is likely to save memory only impact on speed is negligible in general Multithreading Use multithreading or multiprocessing when possible Depending on the nature of the rendered scene performance improvement
319. on is of the form point normal vector point normal vector coordsys x y z P P y y Where coordsys can be one of standard coordinate systems see Table 6 3 or any coordinate system defined by RiCoordinateSystem As an example all the following definitions are valid point pi 1 1 1 declare a point in current coordinate system vector vi vector world 0 0 0 a vector in world coordinates normal NN normal 0 normal in current space Note type promotion Chapter 6 The Shading Language 66 current The default coordinate system in which the renderer performs its work In 3Delight the current space is the same as the camera space object The coordinate system in which the primitive is declared shader The coordinate system in which the shader is declared world The coordinate system active at RiWorldBegin camera The coordinate system of the camera with positive z pointing forward positive x pointing to the right and positive y pointing up cameraname screen A perspective corrected coordinate system of the camera s image plane The range is defined by RiScreenWindow The optional cameraname can be used to specify any camera declared with RiCamera and will transform a point from current space to target camera screen space cameraname raster The 2D projected space of the image The upper left corner of the image is 0 0 with x and y increasing towards their maximum values
320. on on the network cache directory T2020 netcache cached file file lost but lock exist remove lock manually lock name is lockname When 3DELIGHT uses a cached file it locks it so that no other concurrent render removes the file while it is being used This error messages signifies a problem in that a lock exists but the file doesn t This can happen if cached files are deleted manually which is not a good practice To solve the problem the lock file needs to be removed manually removing the entire network cache directory will remove all the locks Chapter 9 Error Messages 192 T2021 netcache lock for file exists but cached file is desynchronized will use original Looks like the found cached file was not supposed to be there Refreshing it T2022 netcache invalid lock file file content text Network cache lock file is probably corrupted This will not cause any rendering arti facts since 3DELIGHT will safely revert to the original non cached file Removing the lock file manually will fix the problem T2023 netcache system clock skewed please fix detected on file filename 3DELIGHT detected an invalid timestamp on some file a timestamp in the future for example When this happens the renderer is not able to update the cache with new files and this could affect performance Fixing the clock or removing the file will fix the problem T2024 netcache cannot delete old lock file lockfile please do
321. on to take when a photon hits a surface The default action is to run the shader and use the resulting color and opacity in combination with the photon shading model as specifyed in photon shading model page 47 Using primitive instead of shader will use object s Cs and Os quantities without any shading shade string camerahitmode shader If this is set to primitive instead of shader the object is assumed to be opaque by the camera This allows the renderer to compute visibility faster without running the surface shader shade viewdependent 0 When using multi camera rendering see Section 7 8 Multi Camera Rendering page 148 this will make the renderer shade each grid one per camera cull integer hidden 1 Specifies if primitives hidden by other primitives are culled or not Specifying 0 to this attribute is only meaningful when baking a shader and could have a significant impact on performance if not used properly cull integer backfacing 1 Specifies if primitives backfacing the camera are shaded or not if RiSides is set to 1 Only meaningful when baking a shader By default cull primitives that are backfacing the camera hider integer composite 1 Enables or disables compositing of transparent surfaces together Any object which has this attribute set to 0 will cause compositing to act is if all the objects behind it did not exist This allows the object to
322. one that caused the shader evaluation using the rayinfo shadeop see rayinfo shadeop page 117 uniform string ray_label rayinfo label ray_label if ray_label approx t do something D else do something more accurate Chapter 7 Rendering Guidelines 128 7 3 4 Trace Group Membership All ray tracing capable shadeops accept a subset parameter which tells 3Delight that traced rays intersect only with geometry which is part of the given group s For example color env trace P Nf subset nearby Intersects only objects that belong to the nearby group The following table lists the meaning of the various strings which can be specified as subset ne Objects which don t belong to any group groupi Objects which belong to group1 groupi group2 Objects which belong to group1 or group2 group1 Objects which belong to group1 or which don t belong to any group groupi Objects which don t belong to group1 Additionally it is possible to specify a default subset in case ray tracing functions do not specify one This is achieved using Attribute grouping tracesubset 7 3 5 Ray Tracing Displacements By default Delight renders ray traced displaced geometry using bump mapping meaning that only surface normals are affected by displacement shaders not geometry It is possible to correctly render such geometry in ray tracing by using Attribute trace displacements 1
323. ons Shad ing is performed on one grid at a time This option specifies the maximum number of such micropolygons per grid The default value ensures that one grid covers approxi mately one bucket Since by default RiShadingRate is one and buckets are 16 by 16 pixels wide the default grid size is 16 16 1 256 Option limits integer eyesplits 6 Specifies the number of times a primitive crossing the eye plane is split before being discarded Option limits integer texturememory 131072 The memory needed to hold the texture for a scene may exceed the amount of core physical memory available To render such scenes efficiently 3Delight uses a memory caching system to keep the texture memory footprint below a predefined threshold This option specifies the amount of memory in kilobytes dedicated to texture map ping algorithms Increasing this parameter may improve texture shadow and environ ment map access performance Note that 3Delight also offers a texture file caching mechanism over networks see Section 7 14 Network Cache page 154 Option limits integer texturesample 1 Specifies the default oversampling value for texture and environment lookups Note that texture O honors this value only if the box filter is selected see Table 6 16 since the gaussian filter is an analytical anisotropic filter which doesn t use super sam pling Also specifying a samples parameter to either texture or environm
324. ookup functions 0 00 cee eee eee 219 10 2 1 3 Transformation functions 0 c eee eee eee 220 10 2 1 4 Message passing and info functions 220 10 2 1 5 File f nctioBs coeur eei Re Her per Id ev 221 10 2 1 6 Ex mpl c ii erre rete Rer tRETERI Ede ER RUE 221 10 2 2 Ihe GX API iode parer E r iiri PUR Eh Ee POPE 222 10 22 21 Entry PointSa sisi inne Or A TEENA EARRA RITEN 222 10 2 2 2 Example Usage ere ee ER EXE ES 224 LA Phe Sx APL nos ised er pre dad RR RR OD PUR PICO REPE 224 102 31 Entry POME erroreari e eE EEA Pere Der Phe 224 10 2 3 2 Example Usage member beh he 227 10 2 4 The Point Cloud API I 227 10 2 4 1 Point Cloud API Data Uvpes 0c eee eee 227 10 2 4 2 Point Cloud Reading ccc e cee eee eee eens 227 10 2 4 8 Point Cloud Winmng eee eee 229 10 244 API Example 0 cece cece n 230 AN SI6 APLI i caved ped hehe RE RE EID eee D eee el hes 230 10 2 6 The Rix Interface AP 239 10 2 7 The VolumeTracer ART 240 10 2 7 1 Working Principles 00 cece eee eee 241 10 277 2 Entry Ponts sete ete eee rer ee 241 10 2 73 Usage Example rrr RR Rb e eh ed 243 10 3 Linking with 3Delight esses 244 10 4 Attaching annotations to shaders esses 245 11 Acknowledeementz arero c cece eee eee 247 12 Copyrights and Trademarks 248 Concept Index sone Ee ER beds Ae e nance ux
325. or A knot vector in the u parametric direction is not in an increasing order P1083 RiNuPatch NURBS specified with invalid vknot vector A knot vector in the v parametric direction is not in an increasing order P1084 invalid object handle passed to ObjectInstance objecthandle RiO0bjectInstance was called with a handle which was not previously declared using a RidbjectBegin P1096 unknown coordinate system coordsys passed to shadeop using world instead An unknown coordinate system was specified to either occlusion indirectdiffuse or gather The renderer will revert to using the world space This could be a typo or a coordinate system not being properly declared by RiCoordinateSystem P1108 wrong number of values for class name type dim found numfound value s This happens when the number of values in a RIB does not make sense for the type For example giving 7 values for P instead of some multiple of 3 P1109 required parameters not provided required parmaname is missing The required parameter was not provided in the RIB This may also happen if there was not at least one complete value for example if P is specified with a single float Chapter 9 Error Messages 184 P1113 unknown filter name filter 3DELIGHT knows the following filters box triangle catmull rom b spline gaussian sinc bessel and mitchell P1117 invalid er
326. ore float VolumeTracer_EvaluateStep varying float rayID output varying float attributes float VolumeTracer EvaluateStep varying float rayID output varying float attributes uniform string shaders Evaluates the volume s attribute midway along the previous step in SIMD All rays must belong to the same grid Parameters are rayID Identifier of a ray previously created with VolumeTracer_InitRay attributes The volume s attributes computed near midpoint along the current step using the density shader specified to VolumeTracer_InitGrid and the interpolation mode specified to VolumeTracer_InitRay shaders optional The list of attribute categories that should be evaluated those categories are identified by the name of the shader that computes them as provided in the grid shader parameter of VolumeTracer_InitGrid By default all attributes will be evaluated but disabling a few of them can improve performance This function returns a varying float success 1 0 or failure 1 0 10 2 7 3 Usage Example Follows a code snippet showing how to use the API Chapter 10 Developer s Corner uniform string objectName nis uniform vector bboxCenter TEE uniform vector bboxSize uniform vector nbCells uniform float nbAttributes Test grid existence if VolumeTracer_GetParameters objectName nbattributes nbAttributes lt 0 Create grid nbAttributes VolumeTracer_InitGrid
327. otion bur 56 particles rotation lessen 56 particles self shadowing 20405 172 performance multiprocessing 122 performance multithreading 122 photon emit option 36 photon ider 33 132 photon maps one D nn 132 photon maps one pass approach 132 photon maps two pass approach 132 photon writemaps option 36 photon estimator esee 48 254 photon reflectance 0 e eee eee eee AT photon shadingmodel 20 000 AT photonhitmode shading attribute 46 photonmap shadeop eee e eee eee 105 Photoshop display driwer 175 PIC display driwer 175 EE 19 piping RIB outnut 2 eee ee 157 plug in filter initialization 163 plug in filter filtering mode 163 plug in filters chaining 0 166 plug in ri Dlters eee eee 162 plug ins geometrg 02008 214 plug ins 18 1 222 certi br eg ee ee bees 209 png tdlmake eee eee eee 19 point cloud AT 227 point based occlusion 0 00 0 e eee eee 130 point based occlusion vs occlusion baking 145 pointcloud gather category sususu 80 PONTE 26er inde a es gba wp EE n 55 ele 55 polygons smoothing normals 53 polymorphism lt 5 2i0 cadusioseeisaddeedebacns 83 pop resizable arrays lesse 71 precomputed photon maps 132 predefined shader variables
328. oud s samples will produce string occlusion Can take values of front back or both Default is front maxsolidangle uniform This is a quality vs speed control when a point cloud is used float Default is 0 1 clamp uniform If set to 1 attempts to reduce the excessive occlusion caused by float the point based algorithm at the cost of speed Default is 0 sortbleeding uniform If set to 1 and clamp is also set to 1 this forces the color bleeding float computations to take the ordering of surfaces into account It is recommanded to set this parameter to 1 Default is 0 coordsystem uniform The coordinate system where the point cloud data was stored string Default is world areachannel uniform Specifies the name of the channel to be used as area of the points string Defaults is area radiositychannel uniform Specifies the name of the channel to be used as radiosity of the string points Default is radiosity or the first color channel if the one specified is not found The channel may be either a single float or a color opacitychannel uniform Specifies the name of the channel to be used as opacity of the string points Default is opacity The channel may be a single float or a color distance output If specified it is set to the average distance of surfaces which con varying tribute to the effect float shadingrate uniform Controls the shading rate for this specific shadeop and overrides float the correspo
329. ounces for a photon to be considered in irradiance computation For example setting a mindepth of 1 will avoid photons that come directly from the light sources meaning that the call will return only indirect light contribution EXAMPLE Perform an irradiance lookup using 100 photons color res photonmap gloabal map P Nf estimator 100 Refer to Section 7 4 2 Photon Mapping page 131 for more details about photon maps float caustic point P vector N This shadeop performs a lookup in the caustic photon map that belongs to the surface being shaded at the surface location described by P N This shadeop can be written using the photonmap shadeop Chapter 6 The Shading Language 107 6 4 6 type type type color caustic point P normal N uniform float estimator 50 uniform string causticmap attribute photon causticmap causticmap attribute photon estimator estimator color c 0 if causticmap 1 c photonmap causticmap P N lookuptype irradiance estimator estimator b return c Table 6 14 caustic shadeop implementation using the photonmap shadeop Texture Mapping texture string texturename float channel texture string texturename float channel float s t texture string texturename float channel float s1 t1 s2 t2 s3 t3 s4 t4 Returns a filtered texture value at the specified texture coordinates
330. ounds Might be invalid or there are not enough float values P1022 RiBlobby leaf requires more values There are not enough values for a leaf Matrices take 16 floating point numbers for example P1023 RiBlobby less leaves than specified There are less leaves in the blobby than declared P1024 PointsGeneralPolygons polygon is either non planar or self intersecting Unable to generate geometry for the given polygon probably because of topological problems with the mesh P1025 unexpected geometry inside transformation motion block A motion block cannot combine both geometry and transforms P1026 more Ri calls than there are time steps in motion block There should be as many Ri commands as motion steps inside a motion block P1027 primitives inside motion block are incompatible object obj Both primitives must have the same general structure P1028 invalid bounding box for primitive or part of object This happens when a bounding box is pushed behind the viewing plane because of bad displacement bounds P1029 cannot find display driver display Display driver display could not be found Possible reasons are bad search paths or misspellings P1030 cannot display string variable v String variable cannot be displayed P1031 unknown display variable var displayname display driver The variable to display is unknown to 3DELIGHT P1032 invalid frame aspect ratio aspectratio The provided image aspec
331. ources To limit shader evaluation to only a subset of lights which effectively contribute to atmosphere one can use the following Only evaluate light sources that are part of the foglight category illuminance foglight currP compute volume attenuation color here Listing 7 15 Using light categories Note that using message passing such as in the following example is not the right way to reject light sources from illuminance loops Remember that shader s parameters are uniform by default and that local variables are varying by default Chapter 7 Rendering Guidelines 162 illuminance currP 1 uniform float isfoglight 1 0 lightsource isfoglight isfoglight if isfoglight 1 0 compute volume attenuation color here b Listing 7 16 Erroneous use of message passing In the erroneous example light sources are evaluated but not included in the result leading to little or no time gain Light categories insure that light sources are not evaluated saving shader execution time It is not uncommon to have tens of light sources in a scene that is why it is important to use light categories especially in volume shaders e Compile shaders with 03 Default option is 02 which does not include some useful optimiza tion e Compile shaders into machine code with dso This pays off with very expensive shaders such as atmosphere shaders e Look for expensive shaders
332. ources is necessary due to excessive network loads Example resources that could benefit from caching e Scene data Such as Maya scene files or specific custom DSO data e Executables Executing files through the network is a non negligible part of the total network traffic Note that 3DELIGHT already caches RIB archives so caching them using this call is not a good idea RtString RxFindFile RtString i category RtString i filename This function allows access to 3Delight s searchpath system It will look for the requested file in the searchpaths of the given category as given by the searchpath option It will also apply any required directory mapping see Search Paths page 39 10 2 1 6 Example Here is a simple example of a DSO using the RxTexture function Note that the rx h file is included instead of the ri h file include shadeop h include rx h A simple DSO shadeop using the Rx Library Notes that extern C is not necessary for c files Only c files need that extern C SHADEOP_TABLE rxTexture color rxTexture string float float float float float float float float float rx init rx_cleanup i y 3 extern C SHADEOP_INIT rx_init return 0x0 No init data extern C SHADEOP_CLEANUP rx_cleanup Nothing to do Chapter 10 Developer s Corner 222 Given a texture file texture coordinates and a width return texture color using a
333. output files produced by 3Delight netcache string includepaths Specifies a colon or semicolon separated list of paths which are always cached even if they are not considered slow access netcache string excludepaths Specifies a colon or semicolon separated list of paths which are never cached even if they are considered slow access User Options ption user type variable value Sets a user defined option Such an option can then be read from inside a shader using the optionO shadeop See option shadeop page 116 A simple example Option user float shadow pass 1 rendering a shadow It is also possible to define user attributes as explained in Section 5 2 6 user attributes page 51 Chapter 5 3Delight and RenderMan 42 RIB Output Options These options are only meaningful when using the C API More details and code snippets can be found in Section 7 15 Outputting RIB page 156 RiO0ption rib archiveprocedurals namepattern RI_NULL When this is set to a non empty string and RIB output is used all RiProcedural calls are modified to use RiProcDelayedReadArchive The required archive is generated and named according to namepattern which should contain the a string to be replaced by a unique number for each archive RiOption rib callprocedurals onoff RI NULL Enables or disables procedurals expansion during RIB output onoff is a string and can be set to either on or off
334. ovided to 3Delight For example specifying a scale of 0 1 means that geometry data is specified in centimeters objects are ten times bigger Continuing with the previous RIB snippet Chapter 7 Rendering Guidelines 138 AttributeBegin Attribute visibility subsurface marble marble light scattering parameters Attribute subsurface color scattering 2 19 2 62 3 00 color absorption 0 0021 0 0041 0 0071 refractionindex 1 5 scale 0 1 shadingrate 1 0 Object s geometry goes here AttributeEnd Surface properties can be obtained from specialized literature A reference paper that contains many parameters such as skin directly usable in 3Delight e Henrik Wann Jensen Stephen R Marschner Marc Levoy and Pat Hanrahan A Practical Model for Subsurface Light Transport ACM Transactions on Graphics pp 511 518 August 2001 Proceedings of SIGGRAPH 2001 Modifying surface Shaders 3Delight renders subsurface scattering in two passes it firsts starts a precomputation process on all surfaces belonging to some subsurface group and then starts the normal render When shaders get executed in the preprocessing stage rayinfo type returns subsurface Using this information a shader can perform conditional execution depending on the context Here is the standard plastic shader changed as to work with subsurface scattering surface simple float Ks 7 Kd 6 Ka 1 roughness 04
335. ow major magic Ox2f0867ab 4 bytes width short 2 bytes height short 2 bytes shadow matrices 32 floats 16 for NP and 16 for Nl 128 bytes image data floats width height 4 bytes NOTE Matrices are stored in row major format class zFile public zFile const char fileName const float np const float nl unsigned short width unsigned short height m file OxO m width width m height height m currentLine 0 m pixelsLeftOnLine width 1 m file fopen fileName wb if m file 1 unsigned magic Ox2f0867ab 203 Chapter 10 Developer s Corner 204 assert sizeof magic 4 fwrite amp magic 4 1 m_file fwrite amp m_width sizeof m_width 1 m_file fwrite amp m_height sizeof m_height 1 m_file fwrite np sizeof float 16 m_file fwrite nl sizeof float 16 m_file zFile if m_file fclose m_file bool Valid const return m_file 0x0 unsigned GetWidth const return m_width unsigned GetHeight const return m_height bool WriteScanline unsigned short y unsigned short size const float data if y m_currentLine size gt m pixelsLeftOnLine return false m_pixelsLeftOnLine size if m pixelsLeftOnLine 0 m_currentLine m_pixelsLeftOnLine m width return fwrite data sizeof float size m_file size private FILE m_file unsigned short m_widt
336. parameters as texture If the given file name is ray trace environment uses ray tracing instead of texture lookups which of course is more expen sive Only geometry tagged as visible to trace rays is considered Attribute visibility trace 1 Optional parameters accepted by this shadeop are listed in Table 6 16 When using ray tracing this environment also accepts the same optional parameters as trace see trace shadeop page 97 EXAMPLE Do an env lookup vector Nf faceforward N I color c environment env tdl vtransform world Nf Only fetch the alpha channel if no alpha present returns 1 float red comp environment env tdl 3 Nf fill 1 Note that this shadeop will return proper linear space colors if the texture has a gamma specification Refer to Section 7 5 Texture Mapping in Linear Space page 140 for details Chapter 6 The Shading Language 109 Name blur sblur tblur width swidth twidth samples fll filter bias usedmipmap expand lerp Type varying float varying float varying float uniform float uniform float uniform float uniform float uniform color uniform string uniform float output varying float uniform float uniform float Default 0 0 0 0 0 1 0 1 0 1 0 16 4 gaussian 0 225 0 0 Description Specifies an additional length to be added to tex ture loo
337. pecified with this method and the one specified with the attribute are added together As an optimization the shader may also have an extra parameter which tells the render if it is actually doing any displacement based on its specific parameter values This allows 3Delight to render more efficiently when a displacement shader is used but set to do no real displacement Here is an example with a simple shader object class bumpy_surface float Km 1 amplitude 1 string texturename float Ka 0 2 Kd 0 8 public constant float __displacementbound_sphere public constant string __displacementbound_coordinatesystem current public constant float __displacement_enabled public void construct __displacementbound_sphere Km amplitude if __displacementbound_sphere gt 0 amp amp texturename __displacement_enabled 1 Chapter 5 3Delight and RenderMan 51 else 1 displacement enabled 0 public void displacement output point P output normal N 1 if texturename float amp Km amplitude float texture texturename P amp normalize N N calculatenormal P public void surface output color Ci output color Oi float diffuse I N diffuse diffuse diffuse I I N N Ci Cs Ka Kd diffuse Oi Os Ci Oi D Note that public members are being used here instead of parameters 5 2 6 User Attributes Attribute user u
338. pecify a translation for a display driver name using the following key displaytype displaydrivername 4s It is also possible to directly specify the library to use for a given display display dso displaydrivername je Note that the translation is still applied before looking up this key Default search paths for different resources are also settable in the rendermn ini file Those could then be extracted using the symbol when specifying search paths using Option searchpath Environment variables are accepted and specified using the VAR convention defaultsearchpath texture je defaultsearchpath shader s defaultsearchpath display je defaultsearchpath archive je defaultsearchpath procedural 4s defaultsearchpath resource s The current directory mapping zone is set using dirmap zone 4s The timeout when waiting for rendering hosts to connect to the master in multi process rendering see Section 7 1 3 Network Rendering page 121 is set in seconds with 3delight networkrender jobtimeout 600 Chapter 5 3Delight and RenderMan 61 Yes Hi at the beginning of a line indicates a comment Specify a gamma correction exposure 1 7 1 3delight specific options option limits texturememory 100000 option limits bucketsize 16 16 option limits othreshold 0 99608 0 99608 0 99608 curves are diced as hair attribute dice hair 1 default shading rate becomes 0 5 shadingrate 1 0 override the shading
339. planes Writes the output TIFF with separate color planes instead of interleaved colors This may help compatibility with some software packages fovn Specifies a field of view in degrees for cubic environment maps Default is 90 degrees mode black clamp periodic smode black clamp periodic tmode black clamp periodic Specifies what action should be taken when accessing a texture using texture or environment outside its defined parametric range s t 0 1 black Sets texture to black outside its parametric range clamp Extends texture s borders to infinity periodic Tiles texture infinitely smode and tmode specify the wrapping modes of the texture in s or t only Default mode is clamp for normal textures and periodic for latitude longitude environment maps Note that while the effects of this option are noticeable mostly when using texture or environment from inside a shader it also slightly changes how the mipmaps of the texture are computed filter box trianglelgaussian catmull rom bessel mitchell sinc Specifies a downsampling filter to use when creating mipmap levels The default filter is sinc All supported filters along with their filterwidth and window defaults are shown in Table 3 1 Chapter 3 Using 3Delight 17 filter filterwidth window Comment box 1 0 x This filter tends to blur textures Use only if texture generation spee
340. plication Different renders send their images to the same i display thus avoiding a proliferation of windows on the desktop Additionally many 3Delight processes can send their images in parallel 2 Re render specific images An image can be rendered again by using the Reload function Note that the best way to use this feature is to launch the render using the renderdl id command without specifying an RiDisplay in the RIB If using RiDisplay is necessary it is mandatory to put the name of the RIB in the filename field Display test rib idisplay rgba 3 Re render crops of a specific image By holding the CTRL key and the left mouse button pressed and then specifying a recangular area on the screen starts a re render of that particular screen region Note that the RIB shouldn t contain any RiCropWindow statements for this feature to work correctly Comments in 2 also apply here 4 Save rendered images to disk Images can be saved as TIFF files Use color lookup tables LUT This handy feature is intended for high dynamic range output and enables color correction using 3D lookup tables Other features include zoom color picker realtime playback gamma correction full screen mode mipmap viewer image blending and more The user should refer to i display s documen tation for more information about its features menus and shortcuts it is available at http www S3delight com ZDoc i display html 8 2 The framebuffer display d
341. portant when using deep shadow maps since one tile of DSM data takes much more space than a tile from a simple texture Use the network cache as described in Section 7 14 Network Cache page 154 When rendering over a network caching textures locally can save a substantial amount of time We timed speed gains of 1596 and more with heavy production scenes on very large networks more than a hundred of machines Geometry Use higher order surfaces 3Delight runs much more efficiently when provided with high level geometry such as NURBS and Subdivisions Feeding finely tessellated polygons to the renderer is not recommended since it is non optimal in many ways In addition using curved surfaces gives most certainly nicer results no polygonal artifacts Use procedural geometry whenever possible this can have a considerable impact on rendering speed especially in complex scenes 3Delight loads only a procedural object if it is visible and disposes it after use this is beneficial for both speed and memory usage More on procedurals in Section 5 3 8 procedural primitives page 57 Chapter 7 Rendering Guidelines 161 e Use level of detail in complexe scenes More on level of detail at Section 7 13 Level of Detail page 153 Shaders The trend is toward sophisticated looks complex illumination models anti aliased shaders and volume shaders This is why shading can eat up a non negligible slice of the total rendering time It is
342. pp file dont keep cpp file Specifies whether or not to keep the intermediate files generated by the preprocessor They are not kept by default no array check Turns off array run time bound checking Enabled by default use shadeops dont use shadeops Enables disables use of shadeops Enabled by default Chapter 3 Using 3Delight 13 searchpath debug Displays a trace of where shadeops are searched strict Enable strict RSL syntax and semantics see Strict RSL Syntax page 13 v version Prints the compiler version number and exits h help Prints a help message and exits Predefined Macros shaderdl always defines the following macros e DELIGHT e A platform specific macro LINUX DARWIN or WIN32 e DELIGHT VERSION to a numeric value of the form 8501 for version 8 5 1 Optimization Levels shaderdl is an optimizing compiler it implements most of the modern optimization techniques and also adds some special SIMD optimizations Here is the list of optimizations enabled by each 0 level 00 There are no optimizations 01 Enables some basic optimizations that fight against the tendency of SIMD compilers to generate a lot of temporaries and loops Enables SIMD mechanisms Minimizes number of generated temporary variables Reuses temporary variables and SIMD booleans Regroups SIMD loops 02 Sets some aggressive optimization this is the recommended level and also the default It includes
343. primitive respectively This is useful when shading over the surface of the particle is important It is also Chapter 5 3Delight and RenderMan 56 EXAMPLE more efficient to use this feature to declare large groups of spheres disks and patches instead of declaring each primitive individually It is not recommended to use these high level primitives for small particle like points Note Since spheres are two sided primitives they will render differently from disks patches and particles when the material is not fully opaque and RiSides is set to 2 When using the patch particle type two additional variables are understood by 3Delight constant varying float patchaspectratio Controls the aspect ratio of the patch This is defined as width height and will only modify the patch s height the width being specified by width or constantwidth When constant the aspect ratio applies to all particles varying aspect ratio gives one value per particle constant varying float patchrotation Gives the rotation in degrees of the patch around its center Additionally width constantwidth patchaspectratio and patchrotation are correctly motion blurred WorldBegin Translate Color 1 1 AttributeB Rotate Rotate 6 Scale 0 Render Points pr L const 0 0 10 1 egin 30010 0100 3 0 3 0 3 Some points using the sphere primitive 321321 301 101101301 1 411 41 32 1 32 1 30 1 10 110 130 1 1 4 11
344. process render is different from the multithreading case the image is split in large areas or tiles each tile is assigned to one process 3Delight doesn t know in advance how to efficiently cut the image into such tiles for example a process might be assigned to an empty region thereby leaving other processes to do more work and thereby wasting time This is why 3Delight uses a load balancing strategy that records rendering times for each process and tries to better tile the image for the next render This means that two consecutive renders of a frame will use different tiling strategies and the second render should use less time than the first one refer to Section 7 1 4 Performance Notes page 122 for more details Chapter 7 Rendering Guidelines 121 The tiling strategy can be manually forced using the tiling command line option Section 3 1 Using the RIB renderer page 7 Three different tiling strategies are supported vertical horizontal and mixed For example to use the mixed tiling mode one would write renderdl P 4 tiling m framel rib Thes best splitting strategy depends on the image being rendered choose the tiling so that the complexity is well distributed among the processes Most outdoor scenes should be rendered using vertical tiling so that every process gets its share of the sky region where complexity is usually very low If the complexity is uniformly distributed inside the scene tiling orientation won t make
345. r The facevertex variables specified do not form well defined zones This can be caused by a bad mesh design or small errors in the values P1006 catmull clark subdivision mesh tag tagname has invalid number of arguments Refer to the specification of RiSubdivisionMesh for the required number of arguments P1007 catmull clark subdivision mesh tag tagname contains an invalid vertex index gt index Some vertices may be missing P1011 catmull clark subdivision mesh tag hole contains an invalid face index gt faceindex Some vertices may be missing P1012 catmull clark subdivision mesh unknown tag There may be typing error in the name or it is not supported yet P1013 display parameter param has wrong type The required parameter is not declared properly It is not compatible with the display server Chapter 9 Error Messages 181 P1015 RiBlobby truncated description The blobby description is missing entries P1016 RiBlobby empty description The blobby has no description in the RIB file P1017 RiBlobby unknown field opcode op The operation op is not recognized Maybe a parameter in a previous operation code was omitted P1018 RiBlobby needs at least one non constant leaf All leaves are constants There is no possible surface P1020 RiBlobby invalid operand index An operator parameter operand index is out of bounds It may have been omitted P1021 RiBlobby invalid float index A float index is out of b
346. r the procedural primitive Procedural primitives cannot be used inside a RiObjectBegin RiObjectEnd block They can however contain such a block and use objects declared before themselves with the caveats mentioned below The following parts of the graphics state are not saved and restored for procedural primitives 1 Named coordinate systems created with RiCoordinateSystem 2 Retained geometry objects Ri0bjectBegin Ri ObjectEnd This means that declaring one of the above inside a procedural primitive may affect the graphics state for later procedural primitives Likewise a declaration made after the procedural primitive declaration but before it was needed by the renderer may affect it It is therefore necessary to declare the required elements before the procedural primitives that require them and not to replace them until after the end of world block when rendering is complete It also wise to avoid using these declarations inside the procedural primitive itself This behavior is subject to change in future releases depending on user feedback about it Contact us at info 3delight com if these features are important to you Chapter 5 3Delight and RenderMan 58 5 3 9 Object Instances Object instancing is supported with the RiObjectBegin RiObjectEnd and Ri O0bjectInstance APIs 3Delight also supports a RiObjectBeginV API which allows the following parameters to be specified string handleid This specifies the handle 3Delight
347. range compression utility Converts HDR images to low dynamic range TIFFs e ribdepends a utility to list RIB file dependencies and to make site independent packages e ribshrink a utility to compress a series of RIB files e ptcmerge a point cloud file merger e ptc2brick a point cloud to brick map 3D texture converter e ptcview a point cloud file viewer e i display an advanced flip book and display driver capable of sequence playback e lib3delight a library that can be linked to other applications to render images and interrogate shaders The library complies to the RenderMan API The next sections describe each of these tools in more detail 3 1 Using the RIB Renderer renderdl renderdl reads a file containing scene description commands and executes them Such files are commonly called RIB files RIB stands for RenderMan Interface Bytestream There are two kinds of RIB files ASCII encoded RIB files and binary encoded RIB files A binary RIB file is smaller than its ASCII encoded equivalent but an ASCII RIB file has the advantage of being editable in any text editor or word processor To render a RIB named file rib just type renderdl file rib It is possible to render more than one file renderdl filei rib file2 rib file3 rib In this case renderdl reads each file one after the other and the graphic state is retained from one file to another in other words the graphic state at the end of one file is the
348. rce shaders see Section 6 3 Predefined Shader Parameters page 89 color specularbrdf vector L Nr V float roughness Computes the specular light contribution Similar to specular but receives a L variable incoming light vector enabling it to run in custom illuminance loops color specularstd normal N vector V float roughness This is the standard specular model described in all graphic books since 3Delight implements its own specular model in specular color specularstd normal N vector V float roughness 1 extern point P color C 0 point Nn normalize N point Vn normalize V illuminance P Nn PI 2 1 extern vector L extern color Cl vector H normalize normalize L Vn C Cl pow max 0 0 Nn H 1 roughness return C Listing 6 6 specularstd implementation color phong vector Nr V float size Computes specular light contribution using the Phong illumination model Nr and V are assumed to be of unit length As in specular this function is also sensitive to the nonspecular light shader parameter Not available in lightsource shaders Chapter 6 The Shading Language 95 color bsdf vector L normal N Evalutes one of the built in BSDF available in 3Delight L is the incoming light direction and N the surface normal The optional parameters are the distribution related ones from Section 6 4 5 2 The trace Shadeop page 97 H void fresnel vector I
349. re supported R0519 unsupported option opt The given RiO0ption is not supported R0530 RiHierarchicalSubdivisionMesh unsupported subdivision scheme scheme Only catmull clark subdivision surfaces are supported R0531 unsupported hit mode mode The specified ray hit mode is not supported R0532 Camera cameraname is not defined The provided camera name has not been declared with RiCamera V R1172 RilfBegin RiElseIf unknown variable varname in conditional expression An undefined variable was referenced during the evaluation of a conditional expression R1183 parameter parametername of shader shadername should be made varying for best performance when ray tracing object objectname For best performance setting uniform shader parameters from uniform primitive vari ables should usually be avoided The primitive variable should be made constant or the shader parameter should be made varying R2000 object prim displacement shader surface shader has no displacement bound but was displaced by dispbound in eye space A displacement shader was attached to an object that doesn t have any displacement bounds This could cut off displaced parts of the object A displacement bounds should be specified for the object dispbound must be increased R2001 object rim displacement shader surface shader exceeded its displacement bound by dispbound A displacement bounds is
350. rendering pipeline that already uses shadow maps No modifications are nec essary in shaders when changing shadow map format normal or deep the shadow shadeop works with both formats Before throwing DSMs into the production pipeline consider the following facts e More expensive to compute Generating good DSMs is generally slower than shadow maps This is often the case when many PixelSamples are used during the generation step e Needs more disk space DSMs can grow quite large mainly for two reasons 1 DSMs are mipmapped by default 2 More data is stored per texel Using the midpoint option to produce deep shadow maps can lead to unpredictable results For deep shadow map creation please refer to Section 8 8 dspy dsm page 171 7 2 4 Aggregated Shadow Maps Aggregated shadow maps are a collection of standard shadow maps concatenated into one single file A good example of the usefullness of this feature is to generate shadow maps for point light sources in which case six shadow maps are needed per light source one for each cordinal direction In this case having six shadow maps to deal with creates at least two problems 1 Pipeline wise managing six shadow maps is more complicated than managing just one 2 Shaders most commonly light source shaders need to accept six shadow map string parameters which is tedious The aggregation operation is performed by passing the aggregate parameter to the shadowmap displa
351. rface s subdivision rules This eliminates many distortion artifacts due to bilinear interpolation in facevaryings 1 Other subdivision schemes such as Loop and Butterfly are rendered as polygonal meshes Chapter 5 3Delight and RenderMan 55 5 3 2 Parametric Patches All parametric patches are supported RiPatch Specifies a single bicubic or bilinear patch All standard basis matrices are supported bezier bspline catmull rom and hermite RiPatchMesh Specifies a rectangular mesh of bilinear or bicubic patches As with RiPatch all basis matrices are supported It is recommanded to use RiPatchMesh instead of RiPatch when specifying connected surfaces since this is more efficient and more suited to 3Delight s crack elimination algorithm RiNuPatch Specfies a NURBS surface Trimming is supported The following variable types are allowed for parametric patches constant uniform varying vertex and facevarying 5 3 3 Curves Both linear and cubic curves are supported Attaching a normal to the curve geometry modifies the curve s orientation depending on the normal s direction this can be used to render features such as grass The following variables are supported constant uniform varying vertex and facevarying Note uniforms are specified per curve and not per curve segment as was the case in old versions 5 3 4 Polygons All polygonal primitives are supported this includes RiPolygon RiGeneralPolyg
352. ription Overrides global exposure Overrides global quantization Overrides global dithering Overrides global filter Can also be zmin or zmax when outputting the z variable Overrides global filter width and height When set to 0 color is divided by alpha to provide an image with an unassociated alpha channel With AOVs an alpha channel should be explicitely added if it is not equal to the default alpha When set to 0 the output will ignore the matte attribute as set by RiMatte Only works for AOVs When set to 1 for an AOV objects which do not output the variable will be transparent in stead of the usual black Allows each display to show only a subset of the scene objects It has the same seman tics as trace subsets See Section 7 3 4 Trace Group Membership page 128 Allows each display to show contribution only from lights which match the given category specification See Light Categories page 74 This feature works only with the raytrace hider A special environment category is supported and will display only the envi ronment map contribution from the trace shadeop Each different value for this param eter will add a little to the render time Table 5 1 Implementation specific RiDisplay parameters Another useful feature supported by RiDisplay is file name formatting It uses spe cial codes starting with the special character to indicate where to insert useful information
353. river This display driver opens a window and displays the rendered image in it It supports the following parameter string autoclose off If this parameter is set to on the window is automatically closed at the end of the render The default behavior is to leave the window open until the user closes it Note that when 3Delight finishes the render it exits without waiting for the user to close the window opened by this display driver letting the user start multiple renders while keeping the windows open Of course if autoclose is enabled the window is closed automatically 1 They can also be saved to other formats using a user provided conversion application refer to i display s documentation Chapter 8 Display Drivers 169 8 3 The TIFF display driver This display driver writes the rendered image into a TIFF file It is a full featured display driver that is recommended for production work The TIFF is written incrementally meaning that one could display the image at any time this can be useful for long or aborted renders Compressed TIFFs and cropping are supported This display driver understands the following parameters string fullimage on When using RiCropWindow this parameter enables you to create an image of the original size with the cropped region placed inside Areas that are outside the crop window are set to black and alpha 0 This option is useful when compositing a cropped image with a matching
354. rm on a specific rendering algorithm Chapter 6 The Shading Language 79 color trans 0 uniform float num_samples 20 uniform float max_dist 10 point ray_origin 0 vector ray_direction 0 float effectivesamples 0 gather samplepattern P N PI 2 num samples effectivesamples effectivesamples ray direction ray direction ray origin ray origin 1 h else 1 vector normalized ray dir normalize ray direction trans transmission ray origin ray origin normalized ray dir max dist trans effectivesamples Listing 6 4 An example usage of the samplepattern category in gather Note that in this mode it is the else branch of the construct which is executed illuminance In this case gather uses ray tracing to perform the sampling Additionally to variables available to the samplepattern category any variable from surface displacement or volume shaders can be collected surface varname Returns the desired variable from the context of the surface shader that has been hit by the gather ray Variables values are taken after the execution of the shader The typical variable is surface Ci but other variables such as surface N or surface P are perfectly valid Addi tionally varname can be any output variable declared in the shader displacement varname volume varname Returns the desired variable from the context of the displacement or vol
355. rmal float radius float user_data Reads next point from the point cloud file The parameters are pointcloud The handle to the point cloud file as returned by PtcOpenPointCloudFile point normal radius user_data A pointer to a point three floats that will be filled with current point s position A pointer to a point three floats that will be filled with current point s normal A pointer to float that will be filled with point s radius The area of the micro polygon that generated this sample is radius radius PI A pointer to a user buffer of a size big enough to hold all the variables at tached to a point The size of the buffer in floats can be obtained by calling PtcGetPointCloudInfo with request set to datasize Returns 1 if the operation is successful 0 otherwise NOTE point normal radius and user data can be null if their value is not neede void PtcClosePointCloudFile PtcPointCloud pointcloud Closes a file opened with PtcOpenPointCloudFile This function releases all memory allo cated by PtcOpenPointCloudFile 10 2 4 3 Point Cloud Writing PtcPointCloud PtcCreatePointCloudFile const char filename int nvars const char vartypes const char varnames float world2eye float world2ndc float format Creates the specified point cloud file If the point cloud file already exists it will be overwrit ten filename nvars vartype varname world2eye world2ndc form
356. rmal Nf faceforward normalize N I vector V normalize I Ci subsurface P Nf filename bakefile diffusemeanfreepath dmfp albedo albedo scale scale ior ior Ks specular Nf V roughness Here is a summary of the major differences with the one pass techniques 1 The subsurface parameters albedo diffuse mean free path are not set by attribute anymore they are specified to the subsurface shadeop The shading rate of the subsurface pass is simply specified using RiShadingRate in the baking pass 2 There is no more subsurface groups groups are implicitly declared by the geometry rendered and baked in the point cloud file 3 User has the ability to use two different shaders one for the baking pass and one for the final pass This is not possible in the one pass method In normal situations this isn t desirable though most of the code line will be shared between the shaders It is of course necessary not to include the specular component of the illumination model in the pre pass this includes reflections and refractions this is not only inaccurate but also slows down the rendering of the pre pass 7 5 Texture Mapping in Linear Space A good rendering and imagine pipeline correctly tracks the color space of all image assets Indeed serious problems can arise if color space is not properly considered from texture acquisition to the actual rendering One can imagine the following problema
357. rmance to trace from the surface to the light In addition to standard ray tracing optional parameters see Table 6 10 this shadeop also accepts Chapter 6 The Shading Language 99 varying float samplecone Same as for the trace shadeop page 97 uniform float samples Same as for the trace shadeop page 97 3 float occlusion point Pt vector R float samples Computes the amount of occlusion using ray tracing as seen from Pt in direction R and solid angle 2 PI hemisphere Returns 1 0 if all rays hit some geometry totally occluded and 0 0 if there are no hits totally un occluded e Pt and R must lie in current space and R must be of unit length e The optional samples parameter specifies the number of rays to trace to compute occlu sion if absent or set to 0 the value is taken from Attribute irradiance nsamples see Section 5 2 attributes page 44 e This shadeop accepts many optional token value pairs These are explained in Table 6 11 e Moreon ambient occlusion in Section 7 4 1 Ambient Occlusion page 130 and Section 7 7 Point Based Occlusion and Color Bleeding page 145 EXAMPLE Returns the amount of occlusion using default number of samples float hemi occ occlusion P Ng Returns the amount of occlusion for the hemisphere surrounding P uses a rough approximation with 8 samples hemi occ occlusion P Ng 8 Same as above but only consider objects closer th
358. ror b Library is missing one of the ConvertParameters Subdivide or Free entry points and cannot be used A2037 RiReadArchive recursive instantiation of a An archive requires itself recursively It cannot be read properly A2055 RiProcRunProgram cannot communicate with program program This message only appears on WINDOWS platforms and means that 3DELIGHT was unable to write a request to the specified program A2056 RiProcRunProgram error reading output of program program This message only appears on WINDOWS platforms and means that 3DELIGHT was unable to read the result back from the specified program A2057 RiProcRunProgram error reading output of program program Missing request response delimiter OxFF The program procedural doesn t output the needed end of stream delimiter A2058 RiProcRunProgram program program has died program terminated ungracefully This means that RiProcRunProgram was not com pleted correctly It may have crashed or simply not have been written with the required loop to process more than one request A2059 RiProcRunProgram cannot launch program program 3DELIGHT is unable to start the specified program A2060 RiProcRunProgram system returned error syserror 3Delight was unable to run the specified program An error string is provided as a debugging help A2061 RiProcRunProgram pipe creation failed On unix systems this means the the pipe system call has failed
359. ror handler name handler Valid handlers are print ignore and abort P1123 unknown built in RiProcedural procedural expected DelayedReadArchive RunProgram or DynamicLoad The RenderMan interface only describes DelayedReadArchive RunProgram or DynamicLoad as valid procedurals for use with the Procedural RIB statement P1124 invalid geometry after displacement for primitive object This happens when a displacement shader computes invalid values NaN or infinity The shader must be fixed P1165 undefined coordinate system coordsys in shader The coordinate system name given to one of the transform functions in the shader was not declared P1170 invalid display channel name The name of the channel to display could not be understood Check the declaration P1171 RilfBegin RiElseIf expression parse error in expression The given expression could not be understood P1176 invalid relative shading rate ratemultiplier The value is either 0 or negative P1181 invalid subset groupname Format is invalid There might be multiple or H in the subset P2375 primitive is too large for RIB parser A primitive has exceeded an internal limitation of the RIB parser This usually happens because the RIB is corrupted P2378 invalid shading model shadingmodel reverting to matte valid shading models for photon mapping are enumerated in Section 7 4 2 Photo
360. rrent Space so it is necessary to transform it to world space if an environment lookup is intended indirectdiffuse only If specified it is set to the fraction of the sampled cone which was occluded by geometry Enables or disables adaptive sampling Default is 1 enable Doesn t affect point based algorithm Specifies the minimum number of samples for adaptive sam pling Defaults to samples if it is less than 64 and samples 4 otherwise Specifies the falloff curve to use 0 is exponential default and 1 is polynomial This shapes the falloff curve In the exponential case the curve is exp fallof f x hitdist and in the polynomial case it is pow 1 hitdist maxdist fallof f The default value is 0 for no falloff Table 6 11 occlusion and indirectdiffuse optional parameters 5 So setting falloff to 1 gives a linear falloff curve Chapter 6 The Shading Language 103 Additionally for point cloud based occlusion and color bleeding the following parameters are recognized Name Type Description pointbased uniform This has to be set to 1 if point based occlusion and color bleeding float are to be used Default is 0 filename uniform Specifies the name of a point cloud file to be used to compute the string occlusion and color bleeding filenames uniform Like filename but allows several point cloud files to be used string together hitsides uniform Specifies which side s of the point cl
361. rspective fov 35 ArchiveBegin geo AttributeBegin Translate 00 3 Scale 0 25 0 25 0 25 Translate 0 0 5 0 Rotate 120 100 Geometry teapot AttributeEnd ArchiveEnd LightSource spotlight 1 intensity 120 from 5 3 5 2 5 uniform string shadowmap raytrace coneangle 2 lightcolor 111 Attribute visibility transmission 0s Display none null rgb WorldBegin Surface simple bake Ks 0 7 roughness 0 02 string bakefile teapot ptc Attribute cull hidden 0 backfacing 0 ReadArchive geo WorldEnd Display teapot using ptc tif tiff rgb WorldBegin Surface simple using ptc Ks 0 7 roughness 0 02 string bakefile teapot ptc float scale 0 05 ReadArchive geo WorldEnd Listing 7 7 Example RIB illustrating two pass subsurface scattering The simple bake and simple using ptc are listed below Chapter 7 Rendering Guidelines 140 surface simple_bake float Ks 7 Kd 6 Ka 1 roughness 04 string bakefile vector V normalize I Ci Cs Ka ambient Kd diffuse normalize N subsurface P float A area P bake3d bakefile P N radiosity Ci area A interpolate 1 D surface simple_using_ptc float Ks 7 Kd 6 Ka 1 roughness 04 string bakefile color albedo color 0 830 0 791 0 753 color dmfp color 8 51 5 57 3 95 float ior 1 5 scale 1 0 no
362. rupted all display driver will receive the DspyImageClose call D2008 failed to write bucket to a display driver returned b Display driver returned an error when attempting to write a bucket Chapter 9 Error Messages 179 D2009 query to display driver a failed display driver returned b Display driver did not specify a image resolution A default one is provided D2045 PixelFilter reset to box 1x1 display driver requirement The display driver cannot accept the specified pixel filter Forced to 1x1 The only display driver that could do this is the dsm display driver D2094 failed to open display driver displayname display driver returned with a null handle Display driver s DspyImageOpen entrypoint did not set the image handle D2202 dspy dsm cannot create a temporary file system error message The deep shadow map display driver requires some temporary files during the render This message means it was unable to create then most likely because of incorrect permissions on the directory it tried to use On linux and OS X the following directories are tried in order DL_TMPDIR TMPDIR tmp and On windows it is VC TMP9 and L2029 cannot setup networking licensing will not work Licensing mechanism requires a network in order work properly L2030 cannot contact license server servername system error syserror Make sure the license server is
363. rying It is wasteful to declare them as varying if they do not change across the lit surface which is almost always the case 2 If these parameters are uniform it might be wiser to use light categories instead see Light Categories page 74 because light categories will exclude light sources prior to evaluation whereas these special parameters will be considered after light source evaluation potentially leading to wasteful work 6 4 Standard Functions 3Delight supports all the standard Shading Language SL built in shadeops and constructs The complete set of standard shadeops is listed below Descriptions are kept brief if any since shadeops are already described in great details in the RenderMan specifications Shadeops marked with contain specific extensions and those marked with are not part of the current standard It is also possible to link shaders with C or C code to add new shadeops see Section 10 1 2 RSL Plug ins page 209 3Delight supports all predefined shader variables It doesn t follow strictly the 3 2 RenderMan Interface specification though some shaders have access to more variables 6 4 1 Mathematics float float float float float radians float degrees degrees float radians sin float radians asin float a cos float radians Chapter 6 The Shading Language 90 float acos float a float tan float radians float atan float a float atan float y float x
364. s Selective ray tracing global illumination and point based graphics Atmospheric effects Textures and Antialiasing High quality filtered textures and selectable antialias filters including the quality sinc and catmull ron filters Chapter 1 Welcome to 3Delight 3 Rich Geometry Support Subdivision Surfaces catmull clark polygons patches B spline Bezier Catmull Rom and others NURBS with trim curves curves quadrics and implicit surfaces blobbies User defined variables including vertex variables attached to geometry are fully supported Procedural Geometry RenderMan procedurals are fully supported Goemetry can be specified in a delayed fashion using either DelayedReadArchive RunProgram or DynamicLoad refer to User s Manual Section 5 3 8 procedural primitives page 57 Fast and Efficient Rendering 3Delight can handle complex scenes made of millions of primitives From its initial design stage rendering speed has been a TOP PRIORITY and it continues to be in its ongoing development Extensible Display Drivers 3Delight comes with the following display drivers framebuffer tiff bmp zfile shadowmap dsm cineon radiance exr and eps Since 3Delight s uses the standard RenderMan display driver interface third party display drivers are also supported New extensions to the display system are also supported including multiple displays per render and display specific quantize parameters See User s Manual
365. s sess ee 112 textureinfo field namen 114 attribute field names i012 co edeeee sees ceases cede edaeed P4 IR ENN 115 option field names ge deele te udm ex ene ee EE ds 116 rendererinfo field names 0 c cece eee cence e 117 rayinfo held nam s ciere epa esent DRY ned ea akan c a DT RiDisplay parameters for edge detection eee 151 Tags written by the TIFF display driver 0 00 cece eee e eee eee 170 ztile fle format A neces cen Giessen B Shae dree d ed 171 Standard parameters passed to Dapvimageipent 0 cece eee eee eee 197
366. s also possible To do so one can concatenate the amp binary string to the file name as shown in Listing 6 7 surface bake2d string bakefile float binary 0 Ci noise s 32 t 16 if binary 1 bake concat bakefile amp binary s t Ci else bake bakefile s t Ci D Listing 6 7 Baking into a binary file Note that baking in 2D space is only appropriate when the underlying surface has a well behaved 2D parametrisation which is often the case in most models that had undergone some UV unwrapping More about baking in Section 7 6 Baking page 141 float bake3d string bakefile string channels point P normal N This shadeops records a set of values to the file bakefile for the given position and normal Values to record are supplied as named parameter pairs For example float occlusion occlusion P N samples maxdist 3 bake3d texturename P N surface color Ci occlusion occlusion Note that the channels parameter is ignored in the current implementation The files created by the bake3d are unfiltered point clouds which can be used directly or converted to brick maps as explained in Section 7 6 3 Brick Maps page 143 in both cases data is directly accessible through texture3d see texture3d shadeop page 111 bake3dO returns 1 if the write is successful and 0 otherwise It takes various optional parameters listed in Table 6 17 Chapter 6
367. s could be linear with the number of processes used Refer to Section 7 1 4 Performance Notes page 122 for details Ray Tracing Avoid ray tracing if possible Ray tracing is inheritantly slow since it implies some intensive number crunching Most importantly it forces 3Delight to retain geometry for the entire render meaning higher memory usage An exception to the above is ray traced shadows in small to medium sized scenes which in our experience render very fast Here is a few advices concerning ray tracing e Use Attribute visibility to specify which objects are visible to traced rays minimizing the number of ray traceable objects is beneficial for both speed and memory usage Additionally 1 Those shaders benefit from properly anti aliased code Chapter 7 Rendering Guidelines 160 using simpler objects stand ins for ray tracing is a good idea those should be made invisible to camera rays Limit maximum ray depth using Option trace integer maxdepth A value of 2 is enough in most cases Remember that increasing this limit may slow down the renderer expo nentially Use grouping memberships to ray trace only a subset of the scene this helps only for large scenes Use shadow maps instead of ray traced shadows Those are faster to generate and are re usable Colored shadows can be rendered efficiently using deep shadow maps See Section 7 2 Shadows page 122 Use environment maps or reflection m
368. s created by bake3d see bake3d shadeop page 110 Its syntax is indeed very similar to bake3d float occlusion texture3d texturename P N surface color Ci occlusion occlusion texture3d returns 1 if the lookup was successful and 0 otherwise It takes various optional parameters listed in Table 6 18 Chapter 6 The Shading Language 112 Name Type Default Description coordsystem string world Specifies the coordinate system from which the values are written filterradius float Specifies the radius of the lookup filter If none is given the renderer computes one that is faith ful to the shaded element derivatives filterscale float 1 A multiplier on the radius of the lookup filter It is not necessary to specify filterradius to use this parameter maxdepth float Sets a maximum depth for lookups If not spec ified maximum depth is used Works for both point clouds and brick maps Table 6 18 texture3d optional parameters 6 4 7 String Manipulation string concat string stri strn Concatenates one or more strings into one string string format string pattern vali valn Similar to the C sprintf function pattern is a string containing conversion characters Recognized conversion characters are 4f e 4g ha Ap c m s 4h Formats a float using the style ddd ddd Number of fractional digits depends on the precision used see
369. s in the scene have been enabled for photon tracing this is required for the automatic photon mapping feature The following option should be used to enable photon tracing for a particular light Attribute light tracephotons on Further details about automatic photon mapping in Section 7 4 2 Photon Mapping page 131 R2385 vtransform or ntransform with a projection matrix will yield unexpected results The vtransform and ntransform shadeops should not be used with projection matrices or with coordinate spaces which involve projections eg raster if using perspective projection It is impossible to correctly project a vector without knowing where it is in space The solution is to turn the vector into two points transform those and build a new vector from the transformed points R5010 renderdl rifend option missing A rifargs option was specified to renderdl but not corresponding rifend was found R5011 renderdl a RI filter must be specified before rifargs A rifargs option was specified to renderdl but not RI filter was specified using the rif option R5012 unable to load RI filter filter syserror 3DELIGHT is unable to load the specified filter The system s error message is shown in syserror R5013 missing RifPluginManufacture in RI filter filter 3DELIGHT was able to load the specified filter but was unable to find the mandatory RifPluginManufacture symbol R5014 missing RifPluginDe
370. s the number of values for varying parameters when evaluating the shader If the list is used to create a shader then this should be 1 as only the first value is use to set the shader s intance parameters The optional i spaceName indicates the space in which the parameters are declared this matters in case of points vectors normals and matrices It defaults to shader if the list is used to create a new shader and current if it is used to evaluate a shader The parameter list will be automatically freed when the context specified by i context is destroyed However SxDestroyParameterList may also be used to destroy the parameter list earlier This is mostly useful for the list passed to SxCallShader SxSetParameterListGridTopology SxParameterList i_paramList unsigned i numGrids const unsigned i_uRes const unsigned i vRes Sets a parameter list to be interpreted as grids instead of independent points i uRes and i vRes are two arrays of i numGrids values which specify the number of points of each grid in both axis Using this function affects the behavior of area and filtered functions in the shader SxSetPredefinedParameter SxParameterList i paramList const char i_predefParamName SxData i values bool i varying true Sets or adds a predefined variable to the specified parameter list Predefined parameters are P u v etc i paramList Specified parameter list i_predefParamName Predefined variable s name
371. s with a medium dynamic range lower than 10 zones Note that this method may produce bad results on very high dynamic range images white n Sets the luminance value in the image that is mapped to pure white 1 0 in the low dynamic range output image Setting this parameter to a smaller value produces more burning The default action is to set the white point to the maximum luminance in the image which removes burning This option is only meaningful when paired with the simple option because the default algorithm automatically computes the white point Specifying a value of 0 enables a histogram based automatic estimation one can use verbose to display the computed value gamma n Specifies a gamma correction to be applied on the produced image Gamma correction is performed after the range compression algorithm nthreads n hdri2tif can run in a multi threaded mode for increased performance This option specifies how many threads to use This option has no effect when simple is used verbose Displays information while processing the image h Displays a brief help text The following options may be used to further control the dodging and burning algorithm Modifying these options is not recommended nscales n Specifies the number of gaussian convolutions to use when computing luminance in formation for each pixel More gaussians mean a more precise result but also a slower computation Default is 8 sharpness
372. see 0 1 0 output by printf but this is generally not the case since p1 is stored in the current coordinate system the printed value will be the point resulting from the transformation of p1 from world to current So if the camera space is offset by 0 1 0 the output of printf O would be 0 0 0 A different implementation would have been possible where points are kept in their respective coordinate systems as late as possible but that would necessitate run time tracking coordinate systems along with point like variables which is not handy and offer no real advantage Operations on Points point vector The results is a point point point The result is a vector point point The result is point point vector The result is point Operations on Vectors and Normals Any vector type in the following table can be interchanged with a normal vector vector The result is a scalar dot product vector vector vector vector The result is a vector On Correctness The shader compiler will not by default enforce mathematical correctness of certain operations For example adding two points together makes no real sense geometrically one should add a vector to a point but this is still accepted by the shader compiler although with a warning Historically in the very first definitions of the RenderMan Shading Language there were no vectors nor normals so everything had to be performe
373. shadeop page 99 Chapter 7 Rendering Guidelines 132 Render fast global illumination previews This is done by directly using the photon maps to compute irradiance at each sample without calling indirectdiffuse In some cases this could lead to acceptable results even for final renders 7 4 2 2 Single Pass Photon Mapping Here is the list of steps required to enable single pass photon map generation 1 Set Option photon emit to the number of photons to trace This indicates to the renderer how many photons are to be traced into the scene This specifies the total number of photons to trace and not a number for each light 3DELIGHT will analyze each light such as to trace more photons from brighter lights The number of photons depends on scene complexity and light placement and can vary between thousands and millions of photons 2 Mark primitives visible to photon rays using Attribute visibility photon 1 Primitive that are not marked as visible to photons will not be included in the photon tracing process 3 Name a global photon map and a caustic photon map using Attribute photon globalmap and Attribute photon causticmap These photon map names can then be used to access the photon maps as explained in photonmap shadeop page 105 It is common to set for the entire scene only one global map for final gathering and one for caustics but it is perfectly legal to specify one per object or per group of objects 4 Se
374. shadeop more about photons maps and final gathering in Section 7 4 2 Photon Mapping page 131 and Section 7 4 3 Final Gathering page 133 color indirectdiffuse string envmap vector dir Returns the irradiance coming from an environment and a given direction dir must be of unit length The environment can be either an environment map or a light probe Environment maps have to be generated by tdlmake with the envcube or envlatl parameter All other textures are interpreted as light probes Probe images generated by software such as HDRShop and stored in other formats such as Radiance files with an hdr extension must be converted by tdlmake to a normal TIFF texture It is perfectly correct and recommended to provide high dynamic range images to this shadeop Refer to Section 7 4 4 Image Based Lighting page 133 for more information Chapter 6 The Shading Language 101 Chapter 6 The Shading Language 102 Name coneangle axis samplebase maxdist environmentmap environmentspace distribution environmentcolor environmentdir occlusion adaptive minsamples falloffmode falloff Type uniform float uniform vector uniform float uniform float uniform string uniform string uniform string Or vector output varying color output varying vector output varying float uniform float uniform float uniform float uniform float Des
375. should use for the object RtObjectHandle and RtString are actually equivalent in 3Delight string scope This specifies at which scope the object should be inserted The default is local which is wherever RiO0bjectBegin is called Other possible values are world which makes the object available for the entire render and global which makes the ob ject available until RiEnd These two require that the handle be specified with handleid Their purpose is to allow a procedural primitive to generate objects lazily and reuse them in other instances of the procedural Note that this will require some synchronization in the procedural s code 5 3 10 Constructive Solid Geometry CSG is fully supported This includes all defined operations on solids union difference and intersection One limitation of the CSG algorithm is that primitives spanning the eye plane might give incorrect results when used in a CSG tree As an extension 3Delight allows putting procedural primitives inside any kind of solid block This behaves as if the content of the procedural was immediately expanded except if the procedural is the first element in a difference block In that case the procedural will act as an implicit union block 5 4 External Resources 5 4 1 Texture Maps 3Delight supports the following optional parameters to the RiMakeTexture API string compression Specifies the compression to apply to the texture Possib
376. side RSL plug ins for example see Section 10 1 2 RSL Plug ins page 209 All classes are declared in file DELIGHT include RixInterface h and are further described in the following sections The RixContext class All Rix Interface class live in a Rix Context The only useful method in this class is GetRixInterface RixInterface RixContext GetRixInterface RixInterfaceID i_id This method constructs and returns the Rix Interface specified by i_id The i_id variable can take one of the following values k_RixThreadUtils k_RixMessages k_RixStats k_RixThreadData k_RixLocalData k_RixGlobalTokenData Returns an instance of the corresponding class RixThreadutils RixMessages RixThreadData etc This method returns a pointer to RxInterface that needs to be cast into the appropriate class For example Get a context RixContext context RxGetRixContext RixMessage error_handler RixMessages context gt GetRixInterface k RixMessages 17 error_handler gt Info This is an example Chapter 10 Developer s Corner 240 The RixInterface class This is the base class for all other Rix classes There is no particular functionality provided by this class apart from returning the version of the API and being the base type returned by GetRixInterface int RixInterface GetVersion const Returns the version of the interface The RixStorage class This class provides data storage and retrieval methods Data
377. sirable if several frames are rendered from the same RIB or application session If this option is set to 1 the licenses obtained for the first render are held until RiEnd is called For renderdl this means until the last RIB is done processing Option licensing string server Allows specification of the license server to use as an option If this is left empty the 3delight licserver key from rendermn ini is used instead Note that this option must be set before the first world block to have any effect Option limits float processmemory O The render will abort with error R5060 if the process memory use in bytes exceeds the specified value A value of zero disables the feature Chapter 5 3Delight and RenderMan 43 Option shadow bias0 shadow biasl render bucketorder render standardatmosphere render volumeshadingrate shutter efficiency shutter offset limits bucketsize limits gridsize limits eyesplits limits othreshold limits texturememory limits texturesample limits zthreshold limits volumegroupsize shadow sample trace maxdepth trace specularthreshold searchpath shader searchpath texture searchpath display searchpath archive searchpath procedural searchpath resource searchpath dirmap searchpath rslpluginmap netcache cachedir netcache cachesize netcache minfreespace netcache writecach
378. ssing factor or size for preview option h for help T0462 size value preview option s argument is not a valid scalar T0463 preview option is ignored size value is out of range An out of range value has been specified to the preview option See Section 3 3 Using the texture optimizer page 15 Chapter 9 Error Messages 191 T0464 missing input gamma for gamma option h for help T0465 input gamma value gamma option s argument is not a valid number The parameter should be a positive scalar T0466 missing input gamma for rgbagamma option h for help T0467 input gamma progname rgbagamma option s argument is not a valid number One of the four values provided to rgbagamma is not valid Each of the four values should be a positive scalar T0468 input gamma value option option s argument is not a positive number T0469 missing color space for colorspace option h for help T0470 color space colorspace colorspace option s argument was not recognized See Section 3 3 Using the texture optimizer page 15 T2013 netcache cannot create cache directory a This looks like some permission problems T2014 netcache cannot create directory network caching disabled The network caching algorithm was unable to create a mutex file for concurrent file access For safety reasons 3DELIGHT will disable all n
379. starting graphic state for the next file If a file cannot be found it is simply skipped This behavior is useful to separate the actual scene description from rendering options For example 4 renderdl fast opt scene rib 4 renderdl slow opt scene rib These render the scene scene rib twice but with different rendering options note that fast opt and slow opt are normal RIB files s1ow opt contains options for high quality rendering such as low ShadingRate and high PixelSamples and fast opt contains low quality speedy option settings If no file name is specified renderdl reads scene description commands from the standard in This feature enables piping commands directly in renderdl For example to enter scene description commands interactively which is not really practical do the following Chapter 3 Using 3Delight 8 renderdl Reading stdin lt enter commands here gt If you wish to pipe the content of file rib in renderdl type cat file rib renderdl renderdl options are described in the following sub section Command Line Options tn pn Specifies the number of threads to use for the rendering n can take any of the following values n0 Use n processors n 0 Use maximum number of processors available n 0 Use all but n processors It is also possible to use this option with a separator like this renderdl t 2 d cubits rib Specifies the number of processes to use for the render
380. string default uniform float 1 varying color 1 Description Specifies a label to attach to the ray Refer to Section 7 3 3 Ray Labels page 127 Specifies a subset of objects which are included in ray tracing computations Refer to Section 7 3 4 Trace Group Membership page 128 Specifies a bias for ray s starting point to avoid poten tially erroneous intersections with emitting surface A value of 1 forces 3Delight to take the default value as specified by Attribute trace bias Can be used to override the shading mode set on the intersected object with hitmode page 46 Only applies when the object s visibility was set with the diffuse specular or int transmission visibility attributes Refer to Primitives Visibility and Ray Tracing Attributes page 45 This can be used to override which sides of surfaces a ray can hit The default is to hit both sides of sur faces with RiSides 2 and the front side of surfaces with RiSides 1 A value of reversed will hit both sides of surfaces with RiSides 2 and the back side of surfaces with RiSides 1 Other possible values are front back and both which act the same regard less of RiSides Can be either specular diffuse or transmission This is accepted by traceQ occlusion indirectdiffuse and gather to override the default ray type The ray type changes which visibility attributes are considered to know if a ray can h
381. t a faceforward version of the normal This is impor tant since we need the original surface normal and not an altered one This also implies that scene geometry should be consistantly oriented in order to get correct results If one is to compute point based color bleeding effects an additional _radiosity channel should be stored in the point cloud file color rad compute_surface_radiance bake3d ptc_file P N coordsystem ptc_coordsys _radiosity rad interpolate 1 Note that point cloud creation should be very rapid so there is no real problem when rendering animated sequences since a point cloud can be created for each frame as apposed to baking where it is a good thing to re use baked data for many frames Point Cloud Use During the main pass only minor modifications are necessary to the occlusion call to use pre viously saved point cloud files An example call looks like this float occ 1 occlusion P N 0 filename ptc file pointbased 1 Color bleeding is computed using the indirectdiffuse shadeop color bleeding indirectdiffuse P N O filename ptc file pointbased 1 An example for point based occlusion can be found in DELIGHT ptc occlusion 7 7 4 Algorithm Control Parameters During the conversion baking pass the important parameters are 1 Camera Placement Camera must see al the elements for which the point based occlusion is to be computed
382. t faceindex float S t type ptexture string texturename uniform float channel float faceindex float s1 t1 S2 t2 S3 t3 s4 t4 Same as texture but acts on ptextures ptexture accepts a list of optional parameters as summerized in Table 6 15 Name Type Default Description blur float 0 Refer to Table 6 16 width float 1 0 Refer to Table 6 16 erp uniform float 0 If set to 1 lookups will be interpolated between the two closest mipmaps This usually achieves higher quality fill uniform color 0 Refer to Table 6 16 filter uniform string gaussian Specifies the reconstruction filter to use when accessing the ptexture map Supported filters are gaussian point bilinear bspline catmull rom box and mitchell The default is mitchell expand uniform float 0 Refer to Table 6 16 Table 6 15 ptexture optional parameters type type environment string texturename channel vector V environment string texturename channel vector V1 V2 V3 V4 Returns a filtered texture value from an environment map for a specified direction As in texture an optional channel can be specified to select a starting channel when performing texture lookups Use tdlmake to prepare cubic and long lat envmaps If an unprepared TIFF is given to environment it is considered as a lat long environment map environement recognizes the same list of optional
383. t lighting with no occlusion it is always possible to call the indirectdiffuse shadeop see image based indirectdiffuse page 100 This shadeop provides a simple way to do diffuse image based lighting without texture blurring and a guaranteed smoothly varying irradiance function indirectdiffuse efficiently integrates the irradiance coming from distant objects as described by the provided environment map No special operations are needed on environment maps the same environment used for standard reflection mapping can be directly Chapter 7 Rendering Guidelines 135 passed as a parameter One could simply call indirectdiffuse with an environment map and the surface normal to get the diffuse lighting as seen by the P N surface element color diffuse_component indirectdiffuse envmap N IMPORTANT Prior 3Delight 7 0 image based lighting was accomplished using occlusion and indirectdiffuse This combination still works as usual but one must be aware that e occlusion uses a less than perfect algorithm to detect the luminous clusters in an environment map e Combining occlusion and indirectdiffuse does not yield to correct results since the diffuse lighting doesn t take the occlusion into account So we strongly recommand using the gather construct instead of the previous method The envlight2 light shader provided with 3Delight combines both the image based occlusion and indirect diffuse lighting and has been
384. t ratio is either too small too close to zero or negative P1033 degenerate screen window The RiScreenWindow is flat on one of its axis left right or top bottom P1034 invalid clipping planes Values passed to RiClipping are swapped or equal far near Chapter 9 Error Messages 182 P1035 degenerate crop window The RiCropWindow is flat on one of the axis left right or top bottom P1036 invalid crop window One or more values passed RiCropWindow is negative or greater than 1 0 P1037 camera to screen matrix too general reverting to identity Current transformation when calling RiProjection is not a 2D x y affine transfor mation P1038 RI_FOV out of range setting to 90 degrees Maximum field of view for RiProjection is 180 degrees P1039 unrecognized projection projection Only perspective or orthographic projections are recognized by RiProjection RI PERSPECTIVE or RI ORTHOGRAPHIC respectively P1040 invalid pixel samples The supplied value is either negative or excessively large P1041 invalid pixel filter width or height The given pixel width or height passed to RiPixelFilter filter is smaller than 1 P1042 invalid depth of field argument s At least one of the arguments passed to RiDepthOfField is less than 0 P1043 invalid shutter range Shutter close time is less than shutter open time P1044 invalid exposure argument s At least one of the arguments passed to RiExposure is less or equal to 0
385. t stringval break case SLO TYPE SHADER printf null break default break if k num elements 1 printf if is_array printf printf n void printArgs const Format i_format Chapter 10 Developer s Corner int main if i format e table 1 printf 4dWMn Slo_GetNArgs for int j 0 j lt Slo_GetNArgs j 236 SLO_VISSYMDEF parameter Slo_GetArgById j 1 if parameter fprintf stderr D1GetText D1Text_2259_param j continue PrintOneParameter parameter i_format if i_format e_prman printf n int argc char argv int i int exitCode 0 Format format e prman int start 1 DlDebug InitErrorSignalsHandling if argc lt 1 strcmp argv 1 h strcmp argv 1 help 1 printf Usage shaderinfo lt option gt file1 fileN n Options n d Outputs declarations in RIB format n Ke Outputs declarations in parsable table format n M Ter Outputs available annotation keys n source Outputs shader s source if embedded Wn methods Outputs shader s methods n iy Oey Shows version to console n version Same as v n sh Shows this help n n Notes Ann No arguments is the equivalent of passing h n All options are exclusive Use no more than one n The options h v and version should
386. t to check for the most common errors but there are still some which are not caught It is also important that your program be written to accept multiple requests include lt stdio h gt include lt stdlib h gt include ri h int main int argc char argv char buf 256 You can still use the standard error output to diagnose your program This allows you to see that your program is started only once even if it is invoked several times in a frame fprintf stderr diagnostic sphere program started n Requests from the renderer to the program are passed on the standard input Each request is written on a single line The detail level required is written first followed by the arguments passed by the user in the RIB The two are separated by a single space while fgets buf 256 stdin NULL RtFloat detail RtColor color 1 0f 1 0f 1 0f sscanf buf Ag g 4g hg amp detail amp color 0 amp color 1 amp color 2 Calling RiBegin with a file name as a parameter causes the commands to be output as RIB to that file when using lib3delight Using stdout or stderr will output the RIB to the standard output or error respectively It is important to call RiBegin RiEnd inside the loop for each request to ensure that the output is received properly by the renderer RiBegin stdout RiColor amp color 0 RiSphere 1 0f 1 0f 1 0f 360 0f RI NULL I Chap
387. t type variable surface string paramname output type variable Functions to access a parameter in one of the shaders attached to the geometric primitive being shaded The operation succeeds if the shader exists the parameter is present and the type is compatible in which case 1 0 is returned Otherwise 0 0 is returned and variable is unchanged Note that assigning a varying shader parameter to a uniform variable fails Also lightsource is only available inside an illuminance block and refers to the light source being examined attribute string dataname output type variable Returns the value of the data that is part of the primitive s attribute state The operation succeeds if dataname is known and the type is correct in which case 1 0 is returned Oth erwise 0 0 is returned and variable is unchanged The supported data names are listed in Table 6 20 User defined attributes are also accessible as in uniform float self illuminated 0 attribute user self illuminated self illuminated if self illuminated 1 do some magic here 4 x varies from 1 to 1 left to right and y from 1 to 1 top to bottom Chapter 6 The Shading Language 115 It is possible to query the attributes of a light source from a surface shader To do so use the attribute shadeop inside an illuminance loop and prefix the attribute name with light illuminance P 1 string name if 1 attribute light identifier
388. t until the plug in is unloaded For output parameters the plug in should assign strings obtained from the RixTokenStorage interface Here is an example which illustrates how to do this Sample plugin which concatenates two strings include RslPlugin h include lt stdlib h gt include lt string h gt int concat RslContext rslContext int argc const RslArg argv RslStringlter retArg argv 0 RslStringIter argi argv i RslStringIter arg2 argv 2 RixTokenStorage token_storage static_cast lt RixTokenStorage gt rslContext gt GetRixInterface k RixGlobalTokenData unsigned numVals RslArg NumValues argc argv Zort unsigned i 0 i lt numVals i Chapter 10 Developer s Corner 212 return 0 extern C 3 size t 11 strlen argl size_t 12 strlen arg2 NOTE dynamic allocation may easily cause horrible performance zi char buffer char malloc 11 12 1 memcpy buffer argi 11 memcpy buffer 11 arg2 12 buffer 11 12 0 This provides a copy of the string which will live long enough l xretArg token_storage gt GetToken buffer free buffer retArg arg1 arg2 static RslFunction pluginFunctions string external_concat string string concat NULL NULL NULL RSLEXPORT RslFunctionTable RslPublicFunctions pluginFunctions NULL NULL 10 1 3 Ri Filter Plug
389. te therefore it is recommended to use un quantized values for this display driver to avoid clipping output colors to 1 1 1 The alpha channel is supported by this display driver but it is not guaranteed to be readable by other software We suggest to use RGB no alpha for maximum portability Three parameters are recognized by this display driver uniform integer setpoints 2 ref_white ref_black This sets the reference black and the reference white values The default values are 180 for reference black and 685 for reference white uniform integer ref_white value Only sets the reference white uniform integer ref_black value Only sets the reference black An explanation of those parameters can be found in the Cineon documentations available on the web The standard extension for a Cineon file is cin IMPORTANT this display driver expects un quantized floating point values so it is important to specify this using RiQuantize Quantize rgb 0 0 0 0 Or directly to the display driver as in Display image cin cineon rgb quantize 0 0 0 0 8 11 Radiance display driver Use this display driver to write files compatible with Radiance Floating point values are required for this display driver since it is intended as a HDRI output The following parameter is recognized by this display driver uniform string colorspace rgb Specifies in which color space to encode the values The two possible values are rgb
390. te that this attribute must be specified with an inline declaration and takes precedence over visibility string transmission Attribute visibility integer photon 0 Specifies if an object is visible to photons Chapter 5 Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute Attribute 3Delight and RenderMan 46 visibility string subsurface Specifies that geometry is visible to subsurface rays This means that affected prim itives are included in subsurface scattering computations and that they belong to the specified subsurface group name Primitives that are in the same subsurface group are considered as forming one closed object A special group name of must be specified for procedural geometry if its contents is visible to several different subsurface groups More on subsurface scattering in Section 7 4 5 Subsurface Scattering page 136 shade string diffusehitmode primitive shade string specularhitmode shader shade string transmissionhitmode shader These attributes determine if the object s shader is run when it is hit by various types of rays A value of shader runs the shader to compute Ci and Oi while primitive uses the object s Cs and Os attributes directly The later is of course much faster shade string photonhitmode shader Specifies the acti
391. ter 10 Developer s Corner 216 Outputting a single OxFF character 377 in octal is the method to Signal the renderer that the program has finished processing this request This can also be done manually if you choose not to use the library to output your RIB RiArchiveRecord RI_VERBATIM 377 RiEnd fprintf stderr diagnostic sphere program is about to end n return 0 This example can be compiled with the following commands Linux g o sphere 03 I DELIGHT include L DELIGHT lib sphere cpp 13delight Mac OS X g o sphere 03 I DELIGHT include L DELIGHT lib sphere cpp 13delight IRIX CC o sphere 03 n32 TARG isa mips4 TARG processor ri0k I DELIGHT include L DELIGHT lib sphere cpp l3delight Windows CL Ox I 4DELIGHTANinclude sphere cpp ADELIGHTANlibN3Delight lib 10 1 4 2 The DynamicLoad Procedural Primitive This example shows how to write a procedural primitive in the form of a DSO It is special in that it calls itself a number of times to create a Menger s Sponge It can be invoked in a RIB stream as such Procedural DynamicLoad sponge 3 1 1 1 1 1 1 The single parameter it takes is the maximal recursion depth It also makes use of the detailsize parameter of the subdivision routine to avoid outputting too much detail Note that 3Delight attempts to find sponge so or sponge dll on Windows and then sponge in the procedural search path This allows you not to specify the e
392. the occlusion shadeop that simulates shadows as cast by a hemi spherical light The shadeop proceeds by casting a specified number of rays in the environment and probing for intersections with surrounding geometry Rays are usually cast uniformly on the hemi sphere defined by surface s point and normal While very useful this technique is not convincing for non uniformly lit environments To overcome this problem 3Delight offers a special gather construct to extract illumination from an environment map passing the environment map as a spe cial category to gather will perform an importance sampling over the environment and provide useful information in the body of the construct S Although one can specify a distribution parameter to occlusion to specify arbitrary ray distribu tions as explained in occlusion shadeop page 99 Chapter 7 Rendering Guidelines 134 environment direction The current direction from the environment map More precisely the current direction describes the center of a luminous cluster in the environment map This direction can be used to trace transmission rays to obtain hard shadows environment solidangle The solid angle for the current direction This can be considered as the extent in space of the luminous cluster currently considered ray direction A random direction inside the luminous cluster described by environment direction and environment solidangle
393. the shading language see Section 6 4 2 noise and random shadeops page 91 They are accessible to both DSO shadeops and RiProcedural code RtInt RxNoise RtInt i inDimension RtFloat i in RtInt i outDimension RtFloat o out RtInt RxPNoise RtInt i inDimension RtFloat i in RtFloat i period RtInt i outDimension RtFloat o out Chapter 10 Developer s Corner 219 RtInt RxCellNoise RtInt i_inDimension RtFloat i_in RtInt i_outDimension RtFloat o_out As input these functions take one to four floats The number of floats is passed by i_inDimension and the values by i_in The expected number of dimensions as a result should be passed by i_outDimension only one and three are accepted It is important to provide a big enough o_out buffer to contain the output The i_period parameter for RxPNoise should contain as many periods as there are input dimensions A return value of 0 indicates a sucess RtFloat RxRandom returns a random number exactly as the float random shadeop 10 2 1 2 Texture lookup functions There are three texture lookup functions with several variants for each They call respectively the implementations of environment shadow and texture in the shading language see Section 6 4 6 texture mapping shadeops page 107 RtInt RxEnvironmentPoints1 RtString i fileName RtInt i nPoints RtInt i_firstChannel RtInt i nChannels const RtPoint i_dir RtFloat o_result RtInt RxShadowPoints1
394. tic case 1 An artist paints a texture on his calibrated monitor using a screen gamma of 2 0 2 A lighting artist puts that texture on an object with his screen gamma set to 1 7 3 Since the texture in step 1 has not been properly linearized the lighting artist will find it difficult to properly match the texture with surrounding environment because it has been created in a different color space The problem above can be avoided if all the artists work in linear color space and with well calibrated monitors Still it is sometimes difficult to get the original source image in linear color space for example an image could be provided by a third party and a conversion is necessary to bring the image into linear space Another part of the problem is that many algorithms in computer graphics are only correct in linear space two such algorithms are texture blurring and texture filtering A somewhat unexpected implication of this is that performing the mip mapping Chapter 7 Rendering Guidelines 141 process using the tdlmake utility produces wrong mipmaps if the input image is not in linear space Another unexpected result is that the texture filtering performed by texture and the likes see texture shadeop page 107 on non linear images also results in slightly incorrect images To elegantly solve the aforementioned problems tdlmake acknowledges two options see tdlmake options page 15 to specify the color space of the source image
395. tically reduce disk usage for automatically generated RIB sequences ribshrink accepts the following options d dir Specify an output directory prefix dir Specify a prefix for archive names overwrite Allows overwriting of existing files archiveminsize n Minimal size in bytes of extracted archives The size is measured before compression so the actual archives can be smaller binary Enable or disable binary output default is on gzip Enable or disable compression default is on progress Write a trace of what is being done v Output version h Print this help No directories are created by ribshrink If a directory is specified with d or prefix it must exist beforehand 3 8 Using ribdepends ribdepends is a utility to list dependencies in a given RIB file as well as make site independant RIB packages The general command line syntax is ribdepends options file1 file2 filen And the following options are accepted package dir Copies specified RIB files and all their dependencies in dir directory Paths inside RIB files are modified to point into correct locations in the created package Conflicting file names are changed in the package directory and the RIB files Note that this copies all textures shaders and archives necessary for the RIB to render this could result in very large pacakges scale s If used with the package option packaged textures are scaled whenever possible t
396. tio 1 else sizeQ width kDefaultZFileSize sizeQ height kDefaultZFileSize sizeQ aspectRatio 1 memcpy i_data amp sizeQ datalen gt sizeof sizeQ sizeof sizeQ break datalen 207 Chapter 10 Developer s Corner case PkOverwriteQuery PtDspyOverwriteInfo overwQ overwQ overwrite 1 memcpy i_data koverwQ datalen gt sizeof overwQ sizeof overwQ datalen break default return PkDspyErrorUnsupported return PkDspyErrorNone DspyImageData Data is expected in scanline order as asked in DspyImageQpen PtDspyError DspyImageData PtDspyImageHandle i_hImage int i_xmin int i_xmax_plusone int i_ymin int i_ymax_plusone int i_entrySize const unsigned char i_data zFile aZFile zFile i_hImage const float fdata const float i_data if aZFile fdata return PkDspyErrorBadParams h Perform some sanity checks but everything should be fine really gt if i_ymax_plusone i_ymin gt 1 i_xmin 0 i_xmax_plusone aZFile gt GetWidth i_entrySize sizeof float 208 Chapter 10 Developer s Corner 209 return PkDspyErrorBadParams if aZFile gt WriteScanline i_ymin i_xmax_plusone i_xmin fdata return PkDspyErrorNoResource return PkDspyErrorNone h DspylImageClose delete our object PtDspyError DspylmageClose PtDspylmageHandle i_hImage zFil
397. tion Output Cl color varying Outgoing light ray color Ol color varying Outgoing light ray opacity Table 6 6 Predefined Light source Variables Chapter 6 The Shading Language 87 6 2 3 Predefined Volume Shader Variables Name Type Storage Description P point varying Light ray endpoint I vector varying Ray direction pointing toward P E point uniform Position of the eye Ci color varying Ray color Oi color varying Ray opacity ncomps float uniform Number of color components time float uniform Current shutter time as specified by RiShutter dtime float uniform The amount of time covered by this shading sample dPdu vector varying Derivative of surface position along u dPdv vector varying Derivative of surface position along v N normal varying Surface shading normal Ng normal varying Surface geometric normal u v float varying Surface parameters du dv float varying Change of surface parameters S t float varying Surface texture coordinates Cs color varying Same as Ci Os color varying Same as Oi Output Ci color varying Attenuated ray color Oi color varying Attenuated ray opacity Table 6 7 Predefined Volume Shader Variables Chapter 6 The Shading Language 88 6 2 4 Predefined Displacement Shader Variables Name Type Storage Description P point varying Surface position dPdu vector varying Derivative of surface position along u dPdv vector varying Derivative of surface posit
398. tion function RxTransformPoints It looks a lot like the transform shadeop in the shading language Section 6 4 3 geometric shadeops page 92 except that it passes an array of points to transform and accepts a time parameter useful with motion blurred geometry There is also RxTransform which allows a transformation matrix to be retrieved without actually transforming anything RtInt RxTransformPoints RtToken i fromspace RtToken i_tospace RtInt i n RtPoint io pl RtFloat i time The points in io p are transformed from i fromspace to i_tospace at time i time If there is some motion blur and i time is somewhere inside the shutter time interval the transformation interpolates points between the two enclosing time steps A return value of 0 means success RtInt RxTransform RtToken i_fromspace RtToken i_tospace RtFloat i_time RtMatrix o_matrix Computes in o_matrix the matrix to transform points from i_fromspace to i_tospace at time i time A return value of 0 means success 10 2 1 4 Message passing and info functions These functions access state and general information They are respectively the equivalent of attribute O option rendererinfo and textureinfo shadeops in the shading language see Section 6 4 8 Message Passing and Information page 113 RtInt RxAttribute RtString i name RtPointer o result RtInt i resultLen RxInfoType_t Zo resulttype RtInt Zo resultcount RtInt RxOption RtString
399. to be dynamically added to a shader For example these two shaders would produce equivalent behavior surface shader1 output varying color myoutput 0 myoutput Cs surface shader2 1 outputchannel myoutput Cs D If the variable channelname already exists it is simply assigned to If there is some incom patibility in the type of detail of the existing variable then nothing is done value may be of any type except string Output variables should still be declared whenever possible as it is more efficient Note that if outputchannel is called from a light shader or a coshader the output is added to the main shader by default usually the surface so it will be visible to the display system To override this behavior prefix the variable name with light or local void gridmin varying float value void gridmax varying float value These special functions take a varying floating point parameter as input and find out the minimum and maximum values over the entire grid in REYES or shading point set ray tracing These functions are useful to take decisions for an entire set of shading samples For example if it is known that some parameter is less than X for the entire grid then one might skip some particular code branch Not to be confused with min and max shadeops Chapter 6 The Shading Language 119 6 4 9 Co Shader Access shader getshader shader shader_name Get the shader with the specified n
400. trict mode only a warning by default void test surface strict test test Note that for RSL 2 0 shaders there is no need to use the extern keyword since predefined variables are considered as class members e Error when extern declaration has detail mismatch For example void test 1 extern uniform point P P 20 D surface strict testO testQ Will print an error since P should be declared as varying point e Error when assigning to a non output function parameter For example void test float in in 0 surface strict_test float tmp 0 test tmp Will produce and error because in parameter to the test function is not declared as output e Error on ambiguous function call For example void test float test surface strict_test test Will produce an error because it is not clear which function to call Chapter 3 Using 3Delight 15 3 3 Using the Texture Optimizer tdlmake tdlmake preprocesses TIFF PNG JPEG GIF IFF SGI PIC PSD TGA bake RADIANCE and OpenEXR files to convert them into an efficient texture format suitable to 3Delight It can also convert a zfile into a shadow map We recommend running tdlmake on all textures before rendering for two reasons e tdlmake creates a mipmapped version of the original texture allowing 3Delight to produce nicer images more efficiently e 3Delight employs a caching mechanism for texture data whic
401. ts version and copyright information h Shows help text Chapter 3 Using 3Delight 19 Supported Input Formats tdlmake supports most of the common formats used in a production environment TIFF tdlmake supports stripped or tiled TIFFs with 1 to 6 channels Suppported data types are e 1 4 8 16 or 32 bits of unsigned integer data e 8 16 or 32 bits of signed integer data e 32 bits of floating point data Unsigned single channel images grayscale or b amp w can have either MINISBLACK or MINISWHITE photometric Either way the output file tdl is MINISBLACK Signed files are required to have either RGB or MINISBLACK photometric Files with less than 8 bits per sample are promoted to 8 bits per sample in the output Otherwise the output format is the same as the input LogLuv encoded TIFFs are supported and are kept in their LogLuv form when processed TIFFs with JPEG compression are not supported IFF files from Maya software Both RGB and RGBA formats are supported PNG files are supported all formats and bit depths SGI files from Maya software GRAYSCALE GRAYSCALE ALPHA RGB and RGBA formats are supported Note that 16 bits images are not supported PIC files from SoftImage software Both RGB and RGBA formats are supported PSD files from Abobe Photoshop software Both GRAYSCALE and GRAYSCALE ALPHA formats without layers are supported both RGB and RGBA formats with or without layers are supported TGA files developped by
402. ty Controls edge width This can be a fractional number and can be set to smaller than 1 0 to get very thin outlines Note that to have proper anti aliasing on thin outlines one should use higher PixelSamples Controls edge width This can be specified in stead of edgefilterwidth It is relative to the frame width eg 0 001 on a 1k frame will give 1 pixel edges Color of the generated edges Controls edge thickness fadeout with depth near and far specify the depth range in which the fadeout will be performed minwidth spec ifies the minimum outline width Table 7 1 RiDisplay parameters for edge detection At least edgevariables and edgethreshold must be specified to enable edge rendering It works by looking for abrupt variations of one or more output variables over the image For example rendering outlines based on changes in depth would be done with Chapter 7 Rendering Guidelines 152 Declare outline color Quantize outline 255 0 255 0 5 Display depth_outline tif tiff outline string edgevariables z float edgethreshold 0 1 float edgefilterwidth 1 5 The Declare command specifies an aribitrary output variable which is used as a placeholder for edge data A Quantize command is used to specify that the output is to be 8 bit Variables specified with edgevariables in this case only z are the ones processed to detect edges It is possible to use any predefined or user defined output variab
403. um or complex scenes on a local machine The number of threads should be set to the number of physical processors available Some hyperthreaded machines show two processors even if there is only one physical CPU installed on the motherboard using two processes on those architectures won t necessarily improve performance and certainly won t double it It is sometimes desirable to set one more thread than available when the rendering generates a lot of IO such as texture or network access having one more thread will give the operating system the oportunity to switch to an alternate rendering thread while another one is waiting for an IO operation to complete Using multiprocessing is recommanded for scenes where shading time is not important and most processing is spent in visibility computations This usually happens in scenes with very simple shaders Normal production scenes force the renderer to spend much more time in the shading stage especially when using ray tracing and multithreading is the right choice for these When rendering over a network 3Delight uses the TCP IP protocol to gather data from the remote hosts This could put a heavy load on the network and on the machine that starts the render When using a large pool of machines one should make sure that the master machine is fast enough to handle all connections This is particularly important when rendering deep shadow maps over the network There is a fundamental design
404. ume but other usages are of course possible The name of this shader is provided to the initialization function of API see Section 10 2 7 2 VolumeTracer Entry Points page 241 and is handled by the plug in It must have a single output parameter an array of floats Any number of input parameters are allowed and can be initialized when creating the grid usually to provide the name of a point cloud file The RSL plug in library is located in DELIGHT shaders 10 2 7 2 Entry Points float VolumeTracer InitGrid uniform string gridName Creates and initializes a 3D grid to be used by the other API functions Parameters are gridName Name of the grid Might be used later by VolumeTracer NbAttributes or VolumeTracer InitRay Function The other parameters of the grid are specified through name value pairs uniform string paramName Name of the grid parameter uniform type param Value Value of the parameter Supported grid parameters are grid center point Center position of the grid in 3D space grid size vector Size of the grid in each dimension in the same 3D space as the position grid nbcells vector Number of cells in the grid in each dimension grid shader string Name of a surface shader that will be used to compute the attributes of the volume at selected sample points in the grid The shader must have a single output parameter of type float the array can be of any constant size plus
405. ume shader that has been evaluated for the gather ray All comments for the surface case above also apply here All returned variables are those encountered at the closest surface to be hit ray length Returns distance to closest hit 11 All variable names are case sensitive Chapter 6 The Shading Language 80 The following example demonstrates how to compute a simple ambient occlusion effect float occ 0 uniform numSamples 20 float smpDiv 0 gather illuminance P Nf PI 2 numSamples effectivesamples smpDiv J do nothing else occ 1 occ smpDiv environment environmentname The environment category is used to perform importance sampling on a specified environment map Importance sampling can be used to implement image based lighting as shown in the envlight2 s1 shader provided with the 3Delight package Note that no ray tracing is performed importance sampled rays are returned and it is up to the user to perform ray tracing if needed This category unveils three optional parameters further explained in Section 7 4 4 Image Based Lighting page 133 environment color Return the color from the environment map environment solidangle Returns the sampled solid angle in the environment map This is the size of the sampled region and is usually inversely proportional to the number of sampled rays more samples will find finer details in the environment map
406. up menu Silent Command Line Installation It is possible to install 3Delight from the command line without popping the installation dialog and with no questions asked C gt 3delight 7 0 0 setup exe VERYSILENT DIR c Program Files 3Delight This can be useful to automate network installations For example with the PsExec tool and a proper domain setup a command similar to this can be used to install or upgrade 3Delight on pcl and pc2 psexec Wpci pc2 i server public 3delight 7 0 0 setup exe VERYSILENT 2 4 Environment Variables Delight needs only two environment variables to run properly and both should be correctly set by the installer DELIGHT This variable must point to the root of your 3Delight installation PATH DELIGHT bin must be part of this environment variable The following environment variables are not necessary for the proper running of 3Delight but they can be used to enable some special features RISERVER If defined and set to a valid filename this variable forces 3Delight to output all Ri com mands to a RIB file More on RIB output in Section 7 15 Outputting RIB page 156 RIFORMAT Specifies the format of the RIB output can be either ascii or binary DL RIB ARCHIVEPROCEDURALS Enables the rib archiveprocedurals option The main purpose is debugging C API applications DL OUTPUT DIR If this variable contains a valid directory all output file names are post concatenated with it
407. used at the moment Parameters are type Can take one the following values 1 i display defines this function call Chapter 10 Developer s Corner 195 size data PkSizeQuery Queries a default size for the image PkCookedQuery Queries whatever the display driver wants cooked pixels or raw fragment list data Refer to Section 10 1 1 3 Accessing 3Delight s Deep Buffer page 199 for more information about fragment lists If this query is not handled the rendered assumes cooked data PkOverwriteQuery Unsupported For each query a different data structure needs to be filled The structures are declared in DELIGHT include ndspy h A brief description follows Maximum size of the structure to fill A pointer to the data to fill Copy the appropriate structure here See Section 10 1 1 4 display driver example page 202 DspyImageOpen Called before rendering starts It is time for the display driver to initialize data open file s Here is a description of all the parameters passed to this function image This opaque pointer is not used in any way by 3Delight It should be allocated and used by the display driver to pass information to DspyImageData and DspyImageClose For instance a TIFF display driver would put some useful information about the TIFF during DspyImageOpen so that DspyImageData could access the opened file drivername Gives the device driver name as specified by Display
408. used to produce figure Figure 7 2 Figure 7 2 An image rendered using an HDRI map and the envlight2 shader There is no light sources in the scene the shadows are cast from bright regions in the environment Chapter 7 Rendering Guidelines 136 7 4 5 Subsurface Scattering 7 4 5 1 One Pass Subsurface Scattering 3Delight features an integrated subsurface light transport algorithm meaning that subsurface scat tering simulations do not need additional passes Here is an image created with the example included in the 3Delight distribution it can be found in DELIGHT examples subsurface Figure 7 3 Teapot rendered with subsurface scattering enabled Running a subsurface simulation is a three step process 1 Surfaces defining a closed object are marked as belonging to the same subsurface group 2 Subsurface light transport parameters are specified using Attribute subsurface on one of the surfaces that is part of the closed object 3 Object s surface shader is modified to correctly account for subsurface lighting Each operation is further explained below A functional RIB file can also be found in DELIGHT examples subsurface Defining a Closed Object This is done using Attribute visibility subsurface groupname an example RIB snippet AttributeBegin Attribute visibility subsurface marble Object s subsurface light transport parameters go here Object s geometry goes
409. vada IRE 64 ER ME EES 64 6 1 2 2 EE 65 6 1 2 3 Points Vectors and Nommals cece eee ee 65 OZA Matrices isst Evene ie Sead cated sad awe ewes 67 6 1 2 5 ugeet d e dee 68 6 1 2 0 C Sh derS r eee kody Satie OR cand a eek dee omen eked 68 6 L2 7 The Void Type i ieu tage tacos ea ud Pebsche uc ES 68 E Eet EE 69 6 1 3 1 Debemt em r 2 0 dr ebe PE LIA Aoi dg dE es is 69 6 1 3 2 Declaration and Member Selection 0000 69 6 1 3 3 Structures as Function Parameter 69 6 L 3 4 TarutablOns il 329 2 9 a ee YY Ebr a au ese E Y n 69 nM ME TU I C LEM TO 6 L4 1 Static AfrAys cisco Hp Eed RPSL PN nas 70 6 1 4 2 Resizable Ara 70 6 1 5 Variable Cl egeg 251 ANEREN PET T is T 6 1 5 1 Uniform Variables 0000 00000 ccc cece eee nne 71 6 1 5 2 Varying Variables EEN centers se re eens dae 71 6 1 5 3 Constant Variables 00 0 ccc cece eee 72 6 1 5 4 Default Class DBebhaviour 00 000 c ccc cece eee T2 6 1 6 Parameter Liste 72 6 1 6 1 Shader and Shader Class Parameters Lus 72 6 1 6 2 Function Parameters 0 0 0 c cece eect eee nee eee 72 ER rt e Te EE 73 6 1 7 1 Conditional Kxecution 0 000 e eee eee T3 6 1 7 2 Classical Looping Constructs sees 73 6 1 7 3 Special Looping Constructs 0 cece eee eee eee 74 61TA Punetiongi s iiis tu aere stot hen die ead ede dean 82 06 1 7 5 Methods ois et e er eid E ERES RM Ea 84 6 2 Predefined Shader Variables sees 84 6 2 1 Predefined Surface Shader
410. while boolean expression 7 We call them classical since they are present in one form or another in almost all programming languages Chapter 6 The Shading Language 74 statement For example uniform float i 0 while i 10 i i 41 The normal execution of the for while loop can be altered using two special keywords continue 1 This skips the remaining code in the loop and evaluates loop s boolean expression again Exactly as in the C language The major difference with C is the optional parameter l that specifies how many loop levels to exit The default value of is 1 meaning the currently executing loop break 1 This keyword exits all loops until level This is used to immediately stop the execution of the loop s NOTE Having the ability to exit loops seems like a nice feature but usually leads to obfuscated code and flow It is recommended not to use the optional loop level 1 if possible 6 1 7 3 Special Looping Constructs This section describes constructs that are very particular to the RenderMan shading language These constructs are meant to describe in a clear and general way a fundamental problem in rendering the interaction between light and surfaces The illuminance Construct This construct is an abstraction to describe an integral over incoming light By nature this construct is only meaningful in surface or volume shaders since only in these two cases that one is interested to
411. xtension include lt stdlib h gt include lt stdio h gt include ri h if defined _WIN32 define DLLEXPORT __declspec dllexport else define DLLEXPORT endif ifdef cplusplus extern C 3 Refer to http mathworld wolfram com MengerSponge html for information about this fractal Chapter 10 Developer s Corner 217 endif Declarations RtPointer DLLEXPORT ConvertParameters RtString paramstr RtVoid DLLEXPORT Subdivide RtPointer data float detail RtVoid DLLEXPORT Free RtPointer data RtPointer DLLEXPORT ConvertParameters RtString paramstr int depth int malloc sizeof int depth 3 decent default value sscanf paramstr Ad depth return depth RtVoid DLLEXPORT Subdivide RtPointer blinddata RtFloat detailsize int depth int blinddata Simple usage of detailsize to avoid drawing too much detail if depth lt 0 detailsize lt 5 0f Draw a cube RtInt nverts 4 4 4 4 4 4 RtInt verts 3 7 6 2 top face 5 1 0 4 bottom face 7 3 1 5 back face 3 2 0 1 left face 6 7 5 4 right face 2 6 4 0 front face RtFloat points e E EE le ceu ll 1 ad SL 1 1 1 i 1 1 1 1 1 1 2 1 1 1 RiPointsPolygons RtInt 6 nverts verts RI P RtPointer points RI NULL else Recursive call reduce depth and scale the object by 1 3 RtBound
412. y driver as explained in Section 8 7 dspy_shadowmap page 171 For example to aggregate a shadow map to the already existing shadow point shd file one would issue Display shadow point shd shadowmap z integer aggregate 1 There is no limit on the number of shadow maps that can be aggregated together and the resulting shadow map can be queried from inside shaders using a single shadow call The resulting operation of this single call is the accumulation of the opacities of all shadow maps present in the agregated file Parameters passed to shadow O such as blur and samples will be used on all the shadow maps in the aggregated file Note Aggregated shadow maps do not need to be rendered from the same point of view as in the point light example 7 3 Ray Tracing Delight implements a number of ray tracing capabilities to render effects such as reflections refrac tions ray probes transmission probes and soft shadows Many of the standard SL shadeops have been extended to fully take advantage of 3Delight s ray tracing features In a summary trace A function to perform multiple importance sampling operation in order to sample BRDFs and environments This is the function to use to render physically plausible materials The calling syntax is described in trace shadeop page 97 transmission A function to render ray traced shadows The calling syntax is described in transmission shadeop page 98 Chapter 7
413. ygons into a point cloud 146 Listing 7 11 Example of multi camera usage 0 n ene e nas 148 Listing 7 12 Declaring and using a dicing camera 153 Listing 7 13 RIB output using Bifegin 0 eee eee 157 Listing 7 14 RIB output using Dipen 158 Listing 7 15 Using light categories 0 ccc eee eee ee eee een a reeenes 161 Listing 7 16 Erroneous use of message Daag 162 Listing 7 17 Example of a simple Ri plug in filter 00 00 cece eee 164 Listing 7 18 Pseudo code explaining what the renderer does when executing a Ri command DT 165 Listing 10 1 PtDspyRawData structure description 200 Listing 10 2 Accessing lists of fragments deep buffer in display drivers 201 Listing 10 3 PtDspyFragment structure 202 Listing 10 4 An example annotated shader sesssseseseee ee 245 List of Figures 261 Table 3 1 Table 5 1 Table 5 2 Table 5 3 Table 5 4 Table 6 1 Table 6 2 Table 6 3 Table 6 4 Table 6 5 Table 6 6 Table 6 7 Table 6 8 Table 6 9 Table 6 10 Table 6 11 Table 6 12 Table 6 13 Table 6 14 Table 6 15 Table 6 16 Table 6 17 Table 6 18 Table 6 19 Table 6 20 Table 6 21 Table 6 22 Table 6 23 Table 7 1 Table 8 1 Table 8 2 Table 10 1 tdimake Mtei nreo reni a E E AE E AERE E RES I7 Implementation specific RiDisplay parameters 0 e cece e eee eee ee 30 Standard RenderMan options and their default values

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