Rapid Prototyping refers to a series of technologies that allow the automatic fabrication of physical objects directly from computer files. These techniques are quite new, the first, called Stereolithography, being introduced commercially only about fifteen year ago. Since then, Stereolithography has been joined by a half dozen other technologies who now represent an important area of commercial activity and exercise a growing impact on the way products are designed and developed.

Previously, making a high quality physical model of a design concept required the skills of a model maker. This is a costly process offering many opportunities for errors. Rapid Prototyping aims to streamline the passage from the virtual concept to its physical representation, rapidly and error-free.

No matter which Rapid Prototyping technology is involved, the process of creating the part is relatively similar. The 3D computer file representing the part is sliced into thin layers a few thousandths of an inch thick. The contour of each of these layers is then fed to the Rapid Prototyping machine to create the layer of physical material in the appropriate shape. Starting at the bottom of the part, the physical layers are produced in sequence and stacked atop one another until the entire part is finished. Fabricating such an object is far from instantaneous and will certainly take more time than printing its two dimensional image. Compared with hand fabrication however, the term Rapid Prototyping is quite justified.

Many Rapid Prototyping technologies are still being developed in industrial and university research laboratories. The combination of speed, high accuracy and low cost is still an ideal to be attained. The future will undoubtedly see the arrival of new techniques offering designers possibilities that defy the imagination. Think of being able to automatically "print" a fully functional prototype incorporating the materials, colours and finishes that are envisioned for production!