Hollowing objects with uniform wall thickness

In rapid prototyping, we can significantly reduce the building time and expensive RP material consumption by building a hollowed prototype instead of a solid model. Presented in the paper is a new method to hollow out solid objects with uniform wall thickness to speed up the part building processes in rapid prototyping systems. To achieve uniform wall thickness, it is necessary to generate internal contours by slicing the offset model of an STL model. Since computing an offset model of an STL model involves many difficulties, this paper proposes a new algorithm that computes internal contours without computing the offset model. The proposed algorithm is efficient and relatively easy to implement, because it employs well-known 2D geometric algorithms, such as planar curve offsetting and tracing innermost curves. Various examples have been tested with implementation of the algorithm, and some examples are presented for illustration.