The execution of "addPhysicalGroup" leads elements missing in output file for 3D meshing (Python Interface)
After meshing a 3d geometry using Python interface, I tried to export the mesh to a '.su2' mesh file. The mesh file should contain elements, points and physicalgroups ('.su2' file is used as an input mesh file to CFD software: SU2, the format is simple and the description can be found in "https://su2code.github.io/docs_v7/Mesh-File/"). If there is no "addPhysicalGroup" executed, the exportion works fine. But when I add a line "gmsh.model.addPhysicalGroup(2, [1], 1)" to specify a "MARKER_ELEMENT" for SU2 run, GMSH does not export elements to the mesh file(NELEM=0). In summary, the execution of "addPhysicalGroup" leads elements missing in output file for 3D meshing. But it's weired that "addPhysicalGroup" works fine for 2D mesing. The code can be viewed here → test_3d.py