Hola Daniel,
The documentation of SMESH files is available in this link:
https://wias-berlin.de/software/tetgen/fformats.smesh.html
I have attached an example of a cube with top elevation (-5 km) and bottom
elevation (-41km). The SMESH can be used to described a closed volume, but you
can use also used to represent surfaces. In FEFLOW, if you have a 3D model (e.g.
layer-based), you can store a Face Selection and then export the faces as SMESH
(simply right-click on the selection name). This is quite practical to learn the
file format behind SMESH, or even quickly build SMESH files using FEFLOW.
Saludos
Carlos
