Hi Ryan, your code seems to be correct (by the way I am not a great expert of Gmsh source code).
I was thinking that maybe the problem is in the geometry definition: element orientations should be consistent all around the surface (triangle normals should point outward). Maybe some of your elements have opposite orientation and thus volume mesh cannot be generated? On which geometry are you testing your program? If you have tried to generate the mesh using the GUI and you have succeeded, probably it's because Gmsh makes a check on orientation. Simone ________________________________ De : [email protected] [[email protected]] de la part de Ryan Durscher [[email protected]] Envoyé : samedi 22 août 2015 6.00 À : Simone GREMMO [531257] Cc : Gmsh; [email protected] Objet : Re: [Gmsh] c++ API - Import mesh vertices and elements Simone, Please see below for sample code. I have tried commenting out those line, but it resulted in the same issue. The error I am seeing is : "Initializing memorypools. tetrahedron per block: 8188. Size of a point: 128 bytes. Size of a tetrahedron: 96 (96) bytes. Size of a shellface: 216 (216) bytes. Error: The point set is trivial." These are tetgen outputs with the "The point set is trivial" being a result of the 0 nodes being input into it. Incidentally if I call refineMesh it properly refines the surface mesh I am inputting into the gmshModel if I comment out the region stuff. From the GUI in order to get a volume mesh I have to use the elementary entities -> add -> volume then select the surface mesh (generated from step *** in the code). This creates a *.geo file which I cant figure out how to replicate though the API. The form of the *.geo file is: Discrete Face(1) = {}; Surface Loop(3) = {1}; Volume(3) = {3}; Physical Surface(1) = {1}; I have been staring at this for a while now and any help would be greatly appreciated. Thanks, Ryan // Gmsh headers #include "Gmsh.h" #include "GModel.h" #include "GEntity.h" #include "discreteFace.h" #include "discreteRegion.h" #include "MTriangle.h" #include "MFace.h" // *verts is a 3*numVerts array of coordinates verts(3*i + 0) = x, verts(3*i + 1) = y, and verts(3*i + 3) = z // *conn is a 3*numTris array - define the triangles connectivity int gmsh_Volume_Mesh(int numVerts, int numTris, double *verts, int *conn) { // Initialize variables int i,j; printf("USING GMSH\n"); GmshInitialize(); GmshSetOption("Mesh","Algorithm",1.); GmshSetOption("General","Verbosity", 100.); //Create Gmsh model and set the factory GModel *modelGmsh = new GModel; modelGmsh->setFactory("Gmsh"); // Create a discrete face GFace *interFace = new discreteFace(modelGmsh,1); // Pack triangle verts into vertex vector std::vector<MVertex*> vertex; vertex.resize((int) numVerts); for (i = 0 ; i < numVerts ; i ++) { vertex[i] = new MVertex(verts[3*i + 0], verts[3*i + 1], verts[3*i + 2], interFace, i+1); // Want index to start at 1 // Add vertex to face interFace->addMeshVertex(vertex[i]); } // Pack connectivity of triangles into face for (i = 0; i < numTris; i++) { interFace->addTriangle(new MTriangle(vertex[conn[3*i + 0]-1], vertex[conn[3*i + 1]-1], vertex[conn[3*i + 2]-1]));/*, i+1,2));*/ } printf("Number of elements in face = %d\n",interFace->getNumMeshElements()); // Add face to model modelGmsh->add(interFace); // ****** modelGmsh->writeGEO("test.geo"); // ****** modelGmsh->writeMSH("test.msh"); // Create face loop - only 1 surface std::vector<GFace*> interfaceFace; //in my case the surface is given in one piece only interfaceFace.push_back(interFace); std::vector <std::vector<GFace*> > interfaceLoop; interfaceLoop.push_back(interfaceFace); // Create a physical region GRegion *regionInterface = modelGmsh->addVolume(interfaceLoop); //Add a volume physical entity regionInterface->addPhysicalEntity(1); //Add the region to the model modelGmsh->add(regionInterface); modelGmsh->writeGEO("test.geo"); modelGmsh->writeMSH("test.msh"); //Mesh the model //modelGmsh->refineMesh(1); // Refining the surface mesh works fine if I comment out the region stuff modelGmsh->mesh(3); /*printf("Num Regions = %d\n",gmshmodel->getNumRegions()); printf("Num Faces = %d\n",gmshmodel->getNumFaces()); printf("Num Edges = %d\n",gmshmodel->getNumEdges()); printf("Num Verts = %d\n",gmshmodel->getNumVertices());*/ delete modelGmsh; GmshFinalize(); printf("Done meshing\n"); }
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