Khoshnevis 9634962 As an emerging technology, rapid prototyping is revolutionizing every sector of industry, creating great opportunities to design and manufacture products of superior quality with shorter lead-time and low costs. Methods like selective photocuring, selective sintering, droplet deposition on powder,and 3D printing have been explored by many researchers and practitioners. The major technological constraints for using the rapid prototyping technologies are poor surface finishing, limited size, and dimensional shrinkage of parts. There is a strong need for fabricating large parts, superior surface quality, and better mechanical properties. The proposed research project will develop a Contour Crafting (CC) rapid prototyping system, a new additive fabrication technology, which can produce extremely smooth surface finishing. The Contour Crafting process uses computer control of troweling motion of a forming mechanism to create smooth and accurate planar and free-form surfaces. This is a hybrid method that combines an extrusion process for forming the object surfaces and a filling process to build the object core. The research project has a balance between theory and experiment, and will provide valuable findings for the rapid prototyping industry.