when use 3D mesh smoothing

I am working on a new model and I need to smooth the mesh. I tried 3D Mesh option (I am working with FEFLOW 7.0) but it does not seem to work.
My model is a 3d model with a triangular elements mesh.
When shoud we use this option?

Dear Emilia,

The 3D mesh smooth option is mainy intented for 3D unstructured meshes. If you are having a mesh with prisms, I would recommend you to use "2D Mesh Smooth (with X-Y inheritance in 3D".

Best regards
Carlos Rivera

OK, Thanks