The United States is clearly the world leader in the use of rapid prototyping processes for metal casting applications. Metal casting from RP patterns is widely used by government and industry, cross-cutting numerous markets, including those for automotive, aerospace, medical, and consumer products. The use of RP patterns for investment casting continues to increase as processes evolve and pattern quality improves. There is already a significant number of U.S. companies applying RP to metal casting, as Table 10.1 shows. 3D Systems' stereolithography (SL) process is often used to fabricate patterns for investment casting. The QuickCast build style, coupled with CibaTool and other epoxy resins, is now used by many U.S. companies to fabricate complex patterns quickly for investment casting of metal parts. DTM Corporation's Selective Laser Sintering (SLS) process is used to fabricate investment casting patterns from several materials, including investment casting wax, polycarbonate, and a recently released proprietary material called TrueForm. The use of the SLS process to fabricate investment casting patterns continues to increase as material performance and accuracy improve. To date, however, far fewer SLS machines are in use than SL machines. Other RP processes used in the United States to fabricate investment casting patterns include Stratasys' Fused Deposition Modeling (FDM); Helisys' Laminated Object Manufacturing (LOM); Cubital's Solid Ground Curing (SGC); Sanders Prototype's Model-maker; and BPM (Ballistic Particle Manufacturing) Technology's process. The Soligen Direct Shell Production Casting (DSPC) process yields investment cast parts by directly fabricating an investment casting mold without the use of a pattern.