I don't think Anim8or would be any better for such a task than Wings is (and of the two, I'd use Wings). I think Amapi is a nurbs modeler, but I don't know if it supports the level of precision you would need. Perhaps an Amapi pro could chime in. If it would work there is/was a free version. But I no longer know where to find it. If you are going to press metal for this project it sounds more like it is work related than hobby related. I guess I'm just surprised that what you want to do and the price of Rhino don't intersect. jon

 
~jon
My Blog - Mad Utopia Writing in a new era.