Exporting Fluent .msh file

I recently created a 3D model in cubit. The mesh is a composed of multi-voulmes created from simple curves swept along other curves…etc and also bricks and cylinders. I meshed the entire volume and created side sets composed of the external surfaces of the domain grouped together using groups.
Now I am trying to save it to .msh file to be read by Fluent later on. I get the following message

cubit.cmd(‘Export Fluent “/home/aelg/3dmesh” volume all Overwrite’)
ERROR: Cannot export FLUENT with mixed dimensions
ERROR: Could not export the data to a file.

I also get the same if I did not use the “volume all” part.


After looking at your model, it seems that during your bottom up geometry creation some free surfaces or sheet bodies were not consumed and you have volumes and free surfaces merged together. The Fluent export doesn’t support mixed 2D and 3D elements.

You can see the surfaces/sheets by typing ‘draw volume with is_sheet’

To solve this,

  1. Unmerge the volumes and surfaces with ‘unmerge all’ or Geometry>Volume>Imprint/Merge in the GUI.
  2. Delete all the surfaces ‘delete surface all’ or Geometry>Surface>Delete in the GUI. This will delete all the free surfaces.
  3. Then, try the export again.

Here is the Fluent summary after I exported your file:

Number of dimensions = 3
Number of element blocks = 25
Number of sidesets = 8
Number of nodesets = 0
Number of bc sets = 1
Number of elements = 845196
Number of nodes = 948933