Stereolithography has emerged as a means of quickly creating model and prototype parts without tooling and is becoming a tool designers can use to get products to market faster, reduce development costs, and improve product quality. Applications of stereolithography in the development of injection molded, investment cast, sand cast, and NC machined parts will be covered.In the last several years, a number of market factors have begun to significantly change the nature of product development. Continuing improvements in technology have resulted in significantly shorter product life cycles, requiring that new products get to market in a timely manner. Improved product quality has ceased to be a sales feature and has become instead a minimum requirement to compete in the marketplace. Selling prices have experienced downward pressure from both domestic and foreign competitors.To meet these market challenges, several changes in product development are needed: Products must be developed faster so that market introductions can be done as soon as possible after an opportunity arises. Quality related issues must be addressed early in the product design. To lower selling price, both direct product cost and development costs must be reduced. The introduction of improved CAD/CAM/CAE tools over the last few years has not only improved design productivity, but has provided the means to address these challenges. One of the most significant tools to be developed is a process called stereolithography.