Posted by Precise Simulation on
URL: http://forum.featool.com/Importing-gmsh-mesh-file-with-several-subdomains-tp315p328.html

Thank you for clarifying, now I understand the issue. I will make an update later in the week to allow processing of multiple CAD objects and other fixes. In the meantime here below follows a rather convoluted workaround:

1) Follow the link at the bottom and register for the FEATool with the COVID-19 license if you have not done so already (Registering will allow you to export geometry objects and use functions on the Matlab command line).

2) Restart FEATool.

3a) Import your geometry and process/decompose it so that no geometry object overlap (meaning make copies smaller objects and subtract them from the bigger ones). Then export the decomposed geometry as an OpenCascade *BREP* format CAD file (for example named "decomposed_geometry.brep").

3b) Alternatively, instead switch to the Matlab command line and run the following equivalent commands (using the geom_analyze function to automate this):

    geom = impexp_cad( 'my_path_to/New_Toy_Coil.step', 'import' );
    geom = geom_analyze( geom );
    impexp_cad( 'decomposed_geometry.brep', 'export', geom );

  decomposed_geometry.brep

4) Create a gmsh .geo file with the following structure and run it in Gmsh (Meshing multiple connected subdomains in Gmsh for import in FEATool will only work if the domains are *non*-overlapping and in the Brep format):

    SetFactory("OpenCASCADE");
    Merge "decomposed_geometry.brep";

    Mesh.CharacteristicLengthExtendFromBoundary = 1;
    Mesh.CharacteristicLengthFromPoints = 1;
    Mesh.CharacteristicLengthFromCurvature = 1;
    Mesh.CharacteristicLengthMin = 0;
    Mesh.CharacteristicLengthMax = 16;
    Mesh.MshFileVersion = 2;
    Mesh.SaveAll = 1;

    Mesh 3;
    Save "my_new_mesh.msh";

  my_new_mesh.msh

5) Switch to Geometry mode and (re-)import your STEP or BREP geometry, and delete all but the *largest* geometry object.

6) Import the newly created mesh. No mesh will appear due to a bug.

7) Switch back to geometry mode and then import the mesh again, and your mesh should appear with coupled subdomains and shared internal boundaries.