New concepts in rapid prototyping (RP) have made it possible to build many different kinds of 3D prototype models faster and cheaper than by traditional methods. The 3D models are fashioned automatically from such materials as plastic or paper, and they can be full size or scaled- down versions of larger objects. Rapid-prototyping techniques make use of computer programs derived from computer-aided design (CAD) drawings of the object. The completed models, like those made by machines and manual wood carving, make it easier for people to visual- ize a new or redesigned product. They can be passed around a conference table and will be especially valuable during discussions among.