A 3-D printer seems to be ideal for prototyping parts. I am looking to get a prototype part made for a digiscope adapter for a 1080HD camera (A Pentax Q-S1) for a P8079HP 3 stage cascade tube Image intensifier and 85mm F1.5 Lens on a C-Mount lens adapter for my UFO spotting project. It will also compensate the barrel edge distortion of the $120 Gen 1 Tube with a digital pin cushion filter.

What design software would you recommend? I've tried Autodesk 123D Design but it is pretty horrible to use.