Unpaired faces in mesh, help me please

Hi

I’m looking to run 3D simulation from Gmsh.
I used extruded 2D geometry.
I have run 2D geometry before. but 3D mesh get following error.

ValueError: Unpaired faces in mesh

I read another question about similar problem.
And I think problem is in physical group.
But I cant do anything.

Any help would be greatly appreciated.

+) I don’t know how upload my .geo .msh file :frowning:

This error is normally caused when a face is extruded and it is assumed that the two faces at the end of the extrusion will then remain periodic.

I’m not sure about gmsh, but in pointwise this is often fine but, if you use a high order mesh, the smoothing that occurs can lead to points that can no longer be connected and hence gives this error. I think you will need to some how tell gmsh that the two faces need to be periodic.