Re: Error meshing "Gmsh generated/returned a 2D instead of a 3D grid"
Submitted Questions wrote
Now, the import is working, but the grid generation is not working anymore. The error info is: Gmsh generated/returned a 2D instead of a 3D grid, altough the .step file is a 3D one.
This error indicates that the mesh generator Gmsh could not generate a valid grid for your geometry. In this case it could only manage generate a 2D mesh, possibly only the shell.
Most likely there are some issues with your geometry such as very fine details, regions or boundaries involving very sharp angles, high aspect ratios. I can only speculate, but you could potentially try import your geometry in to Gmsh and see if you can generate a mesh manually, and import the mesh into the FEATool/CFDTool.