gmsh_stl2tet

GMSH_STL2TET creates a tetrahedral mesh from an stl file
 mdl = gmsh_stl2tet(stlfile, maxh, extra) where:
        mdl - EIDORS fwd_model struct
    stlfile - either:
                 - a path to an stl file
               OR
                 - a struct with .vertices and .faces 
       maxh - maximum edge length (default: coarse mesh)
      extra - extra command line options to gmsh

 If stlfile is a struct, stl_write will be called first and an STL file
 written in a temporary location. 

 CASHING: Calls are cashed iff stlfile is a struct.

 NOTE: Only one surface per file is allowed.

 See also CALL_GMSH, STL_WRITE

0001 function mdl = gmsh_stl2tet(stlfile, maxh, extra)
0002 %GMSH_STL2TET creates a tetrahedral mesh from an stl file
0003 % mdl = gmsh_stl2tet(stlfile, maxh, extra) where:
0004 %        mdl - EIDORS fwd_model struct
0005 %    stlfile - either:
0006 %                 - a path to an stl file
0007 %               OR
0008 %                 - a struct with .vertices and .faces
0009 %       maxh - maximum edge length (default: coarse mesh)
0010 %      extra - extra command line options to gmsh
0011 %
0012 % If stlfile is a struct, stl_write will be called first and an STL file
0013 % written in a temporary location.
0014 %
0015 % CASHING: Calls are cashed iff stlfile is a struct.
0016 %
0017 % NOTE: Only one surface per file is allowed.
0018 %
0019 % See also CALL_GMSH, STL_WRITE
0020 
0021 % (C) Bartlomiej Grychtol, 2012-2021.
0022 % $Id: gmsh_stl2tet.m 6276 2022-04-07 07:41:51Z bgrychtol $
0023 
0024 if nargin < 3
0025    extra = [];
0026 end
0027 if nargin > 1 && ~isempty(maxh)
0028    extra = [' -clmax ' num2str(maxh), ' ', extra];
0029 end
0030 
0031 if isstruct(stlfile)
0032     opt.cache_obj = {stlfile.vertices, stlfile.faces};
0033     mdl = eidors_cache(@do_gmsh_stl2tet,{stlfile, extra}, opt);
0034 else
0035     mdl = do_gmsh_stl2tet(stlfile, extra);
0036 end
0037 
0038 
0039 
0040 function mdl = do_gmsh_stl2tet(stlfile, extra)
0041 if isstruct(stlfile)
0042     stem = tempname;
0043     stl_write(stlfile, [stem, '.stl'])
0044     stlname = [stem '.stl'];
0045 else
0046     stem = strrep(stlfile,'.stl','');
0047     stlname = stlfile;
0048 end
0049 %TODO: Some of this could be exposed as options (Algorithm, Optimize, ...)
0050 fid = fopen([stem '.geo'],'w');
0051 fprintf(fid,'Merge "%s";\n',stlname);
0052 fprintf(fid,'Surface Loop(1) = {1};\n');
0053 fprintf(fid,'Volume(2) = {1};\n');
0054 fprintf(fid,'Physical Volume(3) = {2};\n');
0055 fprintf(fid,'Mesh.Algorithm3D=4;\n'); %1=delaunay (tetgen) and 4=frontal (netgen)
0056 fprintf(fid,'Mesh.OptimizeNetgen=1;\n');
0057 fclose(fid);
0058 
0059 call_gmsh([stem '.geo'], 3, extra);
0060 
0061 mdl = gmsh_mk_fwd_model([stem '.msh'],[],[],[]);
0062 
0063 delete([stem '.geo']);
0064 delete([stem '.msh']);
0065 if isstruct(stlfile)
0066     delete(stlname);
0067 end