# Dolfin can't successfully read the xdmf file consisted with tetra and wedge mesh **URL:** \ **Category:** mesh\ **Created:** [April 4, 2024, 1:41am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120 "2024-04-04T01:41:29Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![xirancao](https://avatars.discourse-cdn.com/v4/letter/x/0ea827/32.png) [@xirancao](https://fenicsproject.discourse.group/u/xirancao)\ **Post date:** [April 4, 2024, 1:41am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/1 "2024-04-04T01:41:29Z")
Continuing the discussion from [Gmshio can't successfully read the msh file created by Gmsh](https://fenicsproject.discourse.group/t/gmshio-cant-successfully-read-the-msh-file-created-by-gmsh/14112): When I exported the mesh as .xdmf using meshio, and used dolfin to read the file, it dosen’t work either when the xdmf could be opened with paraview. I tried to export only tetrahedra or wedge, and only the file contained tetraIs could be read. fenics couldn’t read the msh file that contains two and more kinds of mesh? ```python import meshio import matplotlib.pyplot as pt msh = meshio.read("msh_generate.msh") #mesh meshio.write("mesh.xdmf", meshio.Mesh(points=msh.points, cells={"tetra": msh.cells["tetra"],"wedge": msh.cells["wedge"]})) #boundary face meshio.write("mf.xdmf", meshio.Mesh(points=msh.points, cells={"triangle": msh.cells["triangle"],"quad": msh.cells["quad"]},cell_data={"triangle": {"name_to_read": msh.cell_data["triangle"]["gmsh:physical"]},"quad": {"name_to_read": msh.cell_data["quad"]["gmsh:physical"]}})) #boundary cell meshio.write("cf.xdmf", meshio.Mesh(points=msh.points, cells={"tetra": msh.cells["tetra"],"wedge": msh.cells["wedge"]},cell_data={"tetra": {"name_to_read":msh.cell_data["tetra"]["gmsh:physical"]},"wedge": {"name_to_read":msh.cell_data["wedge"]["gmsh:physical"]}})) from dolfin import * mesh = Mesh() with XDMFFile("mesh.xdmf") as infile: infile.read(mesh) mvc = MeshValueCollection("size_t", mesh, 2) with XDMFFile("mf.xdmf") as infile: infile.read(mvc, "name_to_read") mf = cpp.mesh.MeshFunctionSizet(mesh, mvc) boundary_markers=MeshFunction("size_t",mesh,mvc) #print(boundaries.value()) mvc = MeshValueCollection("size_t", mesh, 3) with XDMFFile("cf.xdmf") as infile: infile.read(mvc, "name_to_read") cf = cpp.mesh.MeshFunctionSizet(mesh, mvc) ``` The error is as follows: ```python Traceback (most recent call last): File "meshfile.py", line 15, in infile.read(mesh) RuntimeError: *** ------------------------------------------------------------------------- *** DOLFIN encountered an error. If you are not able to resolve this issue *** using the information listed below, you can ask for help at *** *** fenics-support@googlegroups.com *** *** Remember to include the error message listed below and, if possible, *** include a *minimal* running example to reproduce the error. *** *** ------------------------------------------------------------------------- *** Error: Unable to recognise cell type. *** Reason: Unknown value "mixed". *** Where: This error was encountered inside XDMFFile.cpp. *** Process: 0 *** *** DOLFIN version: 2019.1.0 *** Git changeset: 2e001bd1aae8e14d758264f77382245e6eed04b0 *** -------------------------------------------------------------- ``` ---
**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\ **Post date:** [April 4, 2024, 5:24am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/2 "2024-04-04T05:24:44Z")
Dolfin does not support wedge meshes or Mixed meshes. ---
**Author:** ![xirancao1](https://avatars.discourse-cdn.com/v4/letter/x/839c29/32.png) [@xirancao1](https://fenicsproject.discourse.group/u/xirancao1)\ **Post date:** [April 4, 2024, 5:33am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/3 "2024-04-04T05:33:10Z")
Can other methods be used to implement the boundary layer grid over there? Neither dolfin nor dolfinx can calculate the simulation model with boundary layers? ---
**Author:** ![dokken](https://yyz2.discourse-cdn.com/free1/user_avatar/fenicsproject.discourse.group/dokken/32/1560_2.png) [@dokken](https://fenicsproject.discourse.group/u/dokken)\ **Post date:** [April 4, 2024, 5:43am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/4 "2024-04-04T05:43:36Z")
You would have make a mesh consisting of either only tetrahedra or hexahedral elements. There has been done some work on supporting meshes with mixed cell types, but the work is not complete ---
**Author:** ![xirancao1](https://avatars.discourse-cdn.com/v4/letter/x/839c29/32.png) [@xirancao1](https://fenicsproject.discourse.group/u/xirancao1)\ **Post date:** [April 4, 2024, 8:11am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/5 "2024-04-04T08:11:58Z")
Can’t both dolfin and dolfinx recognize wedge or mixed cell types? If that’s the case, I’m really looking forward to the new version. ---
**Author:** ![francesco-ballarin](https://avatars.discourse-cdn.com/v4/letter/f/f05b48/32.png) [@francesco-ballarin](https://fenicsproject.discourse.group/u/francesco-ballarin)\ **Post date:** [April 4, 2024, 8:42am UTC](https://fenicsproject.discourse.group/t/dolfin-cant-successfully-read-the-xdmf-file-consisted-with-tetra-and-wedge-mesh/14120/6 "2024-04-04T08:42:33Z")
As @dokken said, neither of them currently supports that. There is no ETA on when this feature will land in the new version.