Prototypes are usually made from some type of plastic, and there are many types
of them, and there are also many ways to make them. Most of the time it depends 
on the product and the material your product is going to be made of. If you need to
make a prototype; you will need and Industrial designer, which is basically an engineer
mixed with an artist. These types of people can create the digital files needed for
prototyping manufactures to read. It also helps to have some kind of diagram or sketch
of what you want made. If not then you need a sketch artist or have the
Industrial Designer create one for you. As you can see this is a real prototype of a
virtual representation below. (Tolerances vary)