For the company I work for, we do a lot of entertainment and animal exhibitions, which incorporates fake natural environments with personnel/staff rooms underneath. For example, a penguin exhibition that emulates rocks, stones, etc, in the form of a sloped terrain, and we have maintenance rooms underneath that the general public do not see. So when we create our construction drawings, and more specifically sections, we always fake that sloped terrain thickness with filled regions in Revit.
I know we can turn a toposurface into a polysurface, and I tried the extrude option after getting the polysurface but getting an error. Any ideas on how to make this work?