Hi danperk (SBEECH),

and thank you for your help!

I wanted to do a try by myself and i got the results summarized in the picture example4_capture.PNG that i'm posting here.

In effect the shelling on the extruded object with no internal edges fails with a radius of 2 but works well with radius of 1.5.

I think that this behavior leverages on the internal more complex structure of the object without internal edges.

If i understood correctly Michael's explanations, in this case the internal edges, help Moi to achieving the task.

Nice day,

Marco.