I have a complex solid that I want to shell to a 1mm thickness. I'd be happy if it were just a hollow form 1mm thick. Then I would 3D subtract to top and bottom and add the rest of the bits I need. When I try to do the shell solid, It doesn't seem to treat this drawing as a single shape and only shells pieces of it. The cone section disappears all together. My expectation was I would click on the shape and have a hollow form 1mm thick.