[Gmsh] mesh problem

[stefano zinna]

Dear Sirs.

I converted a .stl file into .geo 
(https://download.yousendit.com/Z01NSU5OOW5samQzZUE9PQ) for gmsh. I'm 
able to generate the surface mesh but it is not able to recognize the 
volume. Is it a problem in the file or it depends on the complexity of 
the geometry?

Thanks in advance for the reply.

best regards,
Stefano Zinna