Only because your model is so complex and the price of C4D does not seem outrageous. I just assumed that if one wanted to create such complex 3D objects in CAD one would need something like Catia or other high end app
you can create very complex models with any of the ploygon modeling aplications out there, even the free blender.
the only advantage nurbs has over polygons is the acuracy and things like beveling and chamfers which can be a nightmare!
but then there are a few cheaper options than CAD software such as Rhino and Moi. useing catia to model is like using a sledge hammer to crack a nut.
bodypaint is actualy now the industry standard for unwrapping geometry and painting directly onto the model. it has nothing to do with rendering, and it is also comes free even with the cheepest option. but ive never used it in any technical illustrations, its mainly for organic stuff.