I believe the new version of AutoCAD can do 3D images, but SolidWorks seems to be more popular for this. I recently had a custom plastic knob designed, and the engineer who drew that for me used SolidWorks, which can generate .IGS and .STL files when can then be viewed with a free 3D viewer app.
Using the .STL file I was then able to have PolyJet samples of the knob made using a stereo lithography process. This only cost a couple hundred bucks and was a useful prototyping step.
