Re: CGAL error in CGAL_Nef_polyhedron3(): CGAL ERROR: assertion violation!
Are you actually running polyhedron twice? If so, why? I am only able to
get that error when I include the doubled call to polyhedron. I'm not sure
why that should be an error, but I never saw it with just one call.
Ok, so I looked at your example and didn't read your text very closely: I
thought it was weird that you were creating two copies of the same shape on
top of each other, but I realized upon further testing that it doesn't
matter where the two copies of the polyhedron are. I checked the face
orientation and it appears to be correct (clockwise).
Have you tried removing sections of the polyhedron?