Export mesh with geometry included

[nicola-sorace]

Hello,

So I'm wanting to use pygmsh for generation of a mesh to use in OpenFOAM. This line is able to export a gmsh mesh:

mesh.write('case.msh', 'gmsh22')

However, it looks like only the actual mesh objects are exported with this, not the geometry. This is a problem because the physical names I assigned to surfaces don't seem to make it through. I can export the geometry with this line:

geom.save_geometry('case.geo_unrolled')

Which produces a file I can open in the gmsh GUI, and generating a mesh in there works great. However, the extra step of running gmsh is annoying. Is there a way of exporting to a msh file in pygmsh with the geometry included?

Possibly related to #264

[nschloe]

Probably related to one of the gmsh bugs in meshio. I don't think anyone takes much interested in the legacy gmsh format 2.2 anymore, so you'll probably have to PR this yourself.

[nicola-sorace]

@nschloe ok, I've looked at the meshio code a bit and it looks like the issue is that the cell_data dictionary is not being populated in the mesh object before writing, only the cell_sets. Does this make sense / is it normal? I'm guessing maybe the cell_sets needs to be converted to cell_data somewhere?

[nschloe]

Or the gmsh writer needs to be modified to understand the cell sets. Not sure which now.

[raptistasos]

Hi, I also confirm that cell_data dictionary is not being populated, which is also a problem for the msh-to-xdmf converters for use in Fenics (which is my intention). Did you find any solution or is there any work around on this issue? Thanks