Non-Uniform Offsetting and Hollowing by Using Biarcs Fitting for Rapid Prototyping Processes

This chapter presents a new method of Non-Uniform offsetting and using biarc fittings to hollow out solid objects or thick walls to speed up the part building processes on RP systems. By building a hollowed prototype instead of a solid part, material consumption and build time can be reduced significantly. A rapid prototyped part with constant wall thickness is important for many different applications of rapid prototyping. To provide constant wall thickness, an Averaged Surface Normals method is developed to find the correct normals to offset the vertices of the STL models. Detailed algorithms are presented to eliminate self-intersections, loops and irregularities of offsetting contours.