Rhino is a program to aid multi dimensional design. The programme allows you to work on various axes which correspond to build up a shape on the screen. You can create solid forms, hollow forms and very complex forms due to the non-uniform design of the program. I think it would take a lot of lessons on Rhino until I would be able to understand it, it is a very complex process.
You can build up faces of an object and add volume to it.
Rhino can be used in the 3D printing design process.
3D Printing
This is a fairly new process in which one can actually print virtually any object or shape using an 'additive process' which layers up material in the form that has been programmed in. This process is often used for prototyping such as small scale architectural models but it has also been used to 'print' human body parts for prosthetics.