I haven't used either Rhino or 3DMax to say if they are more difficult or not. With Carrara you can import an Adobe Illustrator file (*.ai) into a plane of the vertex modeler to extrude and manipulate. I have done this a few times with client logos, and have found it to be relativly painless. An .ai file can be generated from within PhotoShop as well, by outlining what you want with the pen tool, and then saving the path as an .ai file. This is usually pretty quick and clean. I haven't had much success with importing .dxf files into Carrara. For that matter, if anyone out there has some helpful hints for this I would appreciate it. I use Vectorworks for 2D/3D CAD work, but haven't found the magic bullet for converting into C.