I stumbled over a most unusual Rhino behavior. In the attached file, there is a surface object in a one-object group. It is a rather distorted surface, but a valid one. When I use the “RemoveFromGroup” command with “Copy” set to yes, I receive a polysurface.
Why is RemoveFromGroup fiddling around with the geometry at all? Interestingly, the ordinary “Copy” command works just fine, as does RemoveFromGroup without copy. It’s just the combination that seems to freak out Rhino.