Have you asked Maxon tech support about your problem in joining objects? That seems like something that should be possible; there's likely a way to do it within Cinema4D. That program uses meshes as well as parametric solids, so without knowing what sorts of objects you're dealing with it's not possible to answer your question. Rhino is another program that uses a variety of types of surfaces, but if you don't get along with it, there's no reason to import your models into it.

Andrew Werby
www.computersculpture.com