Hi Pilou,

re:
> I don't understand why in case it's a solid section, in the other
> case that is no solid section ?

It's because the object is malformed by a bug in the shell command in the current v5 beta when making a shell with an internal void.

When you use shell set Library = "Solids++" for right now or select a face to make an opening.

The attached file should work ok.

- Michael