What meshes are supported?

[dokken]

See for instance:
https://docs.fenicsproject.org/dolfinx/v0.6.0/python/demos/demo_gmsh.html
https://jsdokken.com/dolfinx-tutorial/chapter3/subdomains.html?highlight=read_from_msh#read-in-msh-files-with-dolfinx

Using the GMSH Python API to generate complex meshes

https://jsdokken.com/dolfinx-tutorial/chapter3/em.html

How to extract and use physical labels from GMSH surfaces on FEniCS (2D mesh)

@AMM Secondly, writing your mesh to xdmf as described in the next snippets works for me: import meshio msh = meshio.read("amm.msh") meshio.write("mesh.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"]})) meshio.write("mf.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"]}, cell_data={"triangle": {"name_to_read": msh.cell_data["triangle"]["gmsh:physical"]}})) from dolfin import * mesh = Mesh() with XD…

and various other posts explaining how to use GMSH with DOLFINx.