ArtMesh User Manual
Contents
1. Import and export of meshes are performed via files Description of file formats is placed in ArtMesh file formats description folder of documentation ArtMesh supports 3 type of files for input output e OBJ Wavefront e VTK ASCII only e STL ASCII and binary 2 How to start the program Files artmesh_cmd exe and artmesh dll must be placed in one folder When artmesh_cmd exe starts it tries to load artmesh dll The message with the result of DLL loading appears in console window The work of the program is controlled by commands written in script language There are three scenarios of program launch 1 Place artmesh_cmd exe and file cmd txt in one folder Text file cmd txt must contain commands on script language Start artmesh_cmd exe It will take commands from cmd txt and execute them 2 Start artmesh_cmd exe with parameter that is the name of command file Commands from this file will be executed For example you can type in file manager artmesh_cmd exe cmd_file txt Commands from cmd_file txt will be executed 3 Start artmesh_cmd exe without command file In this case commands may be typed in console window Command exit or quit or q is used to exit the program artmesh_cmd exe Command can be typed in console window or placed in the end of command file or used as the last parameter of program call For example artmesh_cmd exe cmd txt exit Mesh Quality Hint Using of hard edges can significantly im2. You may not distribute ArtMesh Software in any form without our permission Send your comments questions and suggestions at artmesh topologica org Copyright 2015
3. ArtMesh User Manual 2015 11 20 corresponds to software version 3 4 557 1 About computer program ArtMesh performs quadrilateral and triangular surface meshing Initial data for meshing is rough CAD like triangular surface mesh In other words ArtMesh converts triangular facet into quadrilateral or refined triangular mesh Some triangles usually exist in the mesh which is named quadrilateral here So more correct name for such meshes is quad dominant ArtMesh program have two slightly different modes of work mode ART is used for visualization in computer graphics applications mode TECH is used for CAD CAE applications this version generates volume meshes but it is a work in progress Initial state of program mode is defined at the stage of translation and is available in artmesh dll properties Properties gt gt Details gt gt Product version Program mode can be changed at any time by using command set preset section 4 3 Meshing software component artmesh dll is built as dynamic link library DLL Information about version type 32 or 64 bit is placed in artmesh dll file properties Properties gt gt Details gt gt File description Trial versions of artmesh dll has limited time of use that is specified in file Properties gt gt Details gt gt Product version Console program artmesh_cmd exe is used to launch artmesh dll Artmesh_cmd exe uses text file cmd txt on default with script language commands
4. Parameters in and out in command meshing_file may be omitted if filenames are defined using parameters file_in and file_out Filenames set up in command meshing_file has higher priority than by parameters file_in and file_out If output file is not defined its name is created by adding point and meshing method name to input filename without extension Example file_in cube_1 vtk file_out cube_1 q vtk meshing_file method quad h 3 5 4 3 Parameter presets ArtMesh program have two slightly different modes of work mode ART is used for visualization in computer graphics applications mode TECH is used for CAD CAE applications Initial state of mode is defined at the stage of translation and is available in artmesh dll properties Properties gt gt Details gt gt Product version Program mode can be changed at any time by using command set preset preset_name Two preset_names may be used meshing_tech and meshing_art In command files command set preset must be placed before commands that assign values to parameters that are changed by set preset otherwise parameter values will be reassigned Command set preset changes values of these parameters Configuration parameters TECH ART ridge_angle 36 181 ridge_angle_for_quad 27 50 max_angle_for_quad 160 172 angle_min_in_tri_for_point_insertion 25 10 default value of h_ratio in meshing_file command 0 45 1 0 5 Som
5. ce has local singularities jaggies etc the mesher can think that this is a region with large curvature and the mesh will be condensed at these places It may be unexpected for user So it is necessary to use this parameter carefully for low quality initial surfaces If parameter is set to 0 the curvature is not taken into account Default value is 8 aspect_ratio Parameter sets the limit value for ratio of edge lengths in cell In some points of surface main curvatures can differs significantly and the linear sizes of mesh in curvature directions will be significant different too Parameter aspect_ratio is used to avoid the appearance of too stretched cells The maximum linear size in point will be reduced so the ratio of linear sizes will be close to aspect_ratio Linear sizes ratio is controlled only when aspect_ratio is gt 0 Default value is 3 ridge_angle_for_quad Parameter is used as a condition for joining two triangle cells into one quad cell It is a maximal value of angles between normals of triangles that are adjacent to diagonal edge Both diagonals of future quad are checked If some angle exceeds ridge_angle_for_quad the quad cell formation is not allowed This restriction is used for formation of quads and quad faces of hexahedrons prisms and pyramids Angle is set in degrees Default value is 50 max_angle_for_quad Maximal value for interedge angle Parameter is used as a condition for joining two triangle cells into one qua
6. d cell If some interedge angle in hypothesized quad exceeds max_angle_for_quad the quad cell formation is not allowed Angle is set in degrees Default value is 172 angle_min_in_tri_for_point_insertion Parameter is used only for use_subdivide gt 0 argument of meshing_file command If all interedge angles in triangular cell exceeds angle_min_in_tri_for_point_insertion the new node can be inserted in cell during the process of mesh subdividing Otherwise node insertion is not allowed This restriction is used to avoid the appearance of wedge like cells Angle is set in degrees Default value is 10 skip_short_concave_ridge_edges_num Sets the number of consecutive concave sharp edges that will be excluded from the set of hard edges of initial geometry Parameter takes effect only for isolated chains of sharp edges This parameter is useful for models with accidental sharp edges at poorly refined models Default value is 3 4 2 Some additional parameters which might be useful for software integration dump_log Determine is the writing to log file will be performed Log file s default placement is artmesh_log log txt This path is relative to the folder in which artmesh dll is placed Any command may be executed in silent mode without writing echo to log file using prefix For example dump_log 0 Value range 0 1 Default value is 1 file_in file_out Sets the input and output files for command meshing_file
7. d in 3 quads quads are subdivided in 4 quads Almost all cells become quad when use_subdivide 1 The default value of use_subdivide is 0 out_file_mode Specifies the mode of the output file If output file is STL then out_file_mode binary specifies that file will be binary and out_file_mode ascii specifies that file will be in ASCII form The default value of out_file_mode is binary Examples meshing_file method quad in cube vtk out cube 1 quad vtk h 3 5 use_subdivide 1 meshing_file method tri_orto in cube vtk out cube tri vtk h 3 5 dir path Sets current folder for input output files Example dir e tests exec filename load filename Starts execution commands from file Command load is executed in artmesh_cmd exe command exec is executed in artmesh dll Command load understand command exit that ends work of program artmesh_cmd exe Command exec doesn t understand command exit exit quit q These commands stop application working 4 Configuration parameters Configuration parameters are the global variables of program that can be changed by user At program start these parameters are set to the defaults Some parameters have acceptable range of values New value must correspond to this range Otherwise the new value will not be assigned to parameter Syntax of assigning command par_name par_value Example dump_log 1 Spaces to the left and right of equality sign are not allowed If
8. e technical details for software integration When artmesh dll performs meshing a temporary file artmesh_instance_id_ 0001 is created in the directory where artmesh dll is placed The number in filename corresponds to the number of artmesh dll instance running on a computer First DLL instance creates file artmesh_instance_id_ 0001 second file artmesh_instance_id_ 0002 and so on These files are automatically deleted when artmesh dll instance stops running Meshing progress information is written to these files Example meshing progress stage ms 7 27124 71 065 First numerical column is the stage of meshing it is internal stage that is not important to user second column is time of meshing in milliseconds third column percentage of meshing progress When meshing is finished the word done will be written to file meshing progress done Data exchange between calling program and artmesh dll can be carried out using RAM In this case a set of external functions of artmesh dll is used This possibility is not described in this manual but can be implemented on demand 6 Copyright and disclaimer ArtMesh Software is free for personal usage ArtMesh Software is provided as is without any guarantee made as to its suitability or fitness for any particular use It may contain bugs so the use of this tool is at your own risk We take no responsibility for any damage that may unintentionally be caused through its use
9. parameter name is typed without the value the current value of parameter will be printed to console window Command set par_name default assigns the default value to the parameter Command set default assigns the default values to all parameters Examples dump_log returns current value of dump_log set dump_log default assigns default value to parameter set default assigns default values to all parameters 4 1 Meshing parameters ridge_angle This parameter controls identification of sharp edges of the model It is the limit value for angles between normals of 2 cells adjacent to edge If the angle is larger than this value the edge is considered to be sharp By default the sharp edges become hard edges and they will be saved in generated mesh Using of hard edges can significantly improve the mesh quality Angle is set in degrees Default value is 181 Such value means that no sharp edges will be identified Such approach is good for organic models If you work with hard surface objects it is necessary to determine sharp edges You can use the value for example equal to 43 chords_per_circle Define the discrete approximation of curvature Parameter sets the minimal number of lines or edges for full round at cylindrical part of surface number of chords that describe circumference The account of curvature is useful for meshing at conic and rounded parts of surfaces If the initial surfa
10. prove the mesh quality You can define hard edges of your initial model and these edges WILL BE SAVED in mesh after conversion Edges with sharp dihedral angle can be automatically marked as hard look at ridge_angle parameter Edges of model can be defined manually as hard using file format features Details are described in file ArtMesh file formats date version pdf Now ArtMesh is not good for models with rounded bevels with small radius Using sharp bevels instead of rounded or adding hard edges at the rounded bevels will make mesh better 3 Commands meshing_file method mname in infile out outfile h size use_subdivide sub out_file_mode fmode Command performs mesh generation Required parameters metod Specifies the meshing method metod quad is used for quadrilateral meshing metod tri_orto is used for triangulation Triangles are right angled because this type of triangulation is the pre stage for quadrilateral meshing in Specifies the input file with triangular mesh Quad mesh may be used too Supported file formats STL OBJ VTK out Specifies the output file with generated mesh Supported file formats STL OBJ VTK h Specifies the linear size of cells of generated mesh average edge length Optional parameters use_subdivide Specifies the using of mesh subdividing If use_subdivide 1 the subdividing of quad dominant mesh is performed as the last stage of meshing Triangles are subdivide
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