I use Rhino for a wide variety of things. I make custom jewelry and use Rhino for 3D modeling, both the metalwork and gems. I then render the model in Maxwell Render for approval by my clients. Once approved I send the computer model to a firm in NJ who grows the model with a stereolithography machine and casts it in whatever metal I choose. Oh, that Maxwell is really slick if you're into anything where you need a good idea of the optical properties of a finished piece. I design custom gems in GemCad, import to Rhino, manipulate scale and material properties, export to Maxwell and an hour later have a very good idea of what my gem will look like under any sort of lighting conditions. When you're cutting expensive gem rough it's just invaluable to know what you're going to get before you start cutting.
I also use Rhino to design small precision machines for gem cutting as well as doing larger structural steel objects for a local fabricator. These models are mostly used to check fits and concepts as well as to give the shop guys a better "perspective" on how everything will go together. Once everyone agrees to fit and function I use the "Make 2D" command within Rhino to make the 2D drawings which will be output to AutoCad, cleaned, dimensioned and printed as shop drawings. This works great and the 2D perspective that I print on the 1st page of the shop drawings really helps the fabrication crew see where everything goes without having to spend too much time on interpreting a set of typical 2D drawings.