Method for offset-curve generation for sheet-metal design

Abstract

Offset curves have many applications in computer-aided design and manufacturing. The paper deals with sheet-metal design, where section curves that lie on a design surface must be offset by one metal thickness. Standard techniques for offsetting curves and surfaces are usually too slow for interactive speeds. The paper presents a simple iterative method for computing offset points which can then be splined to generate the offset curve. The method is first developed for the determination of nondegenerate offset curves, and then modifications necessary for the handling of degenerate offset curves are discussed. Implemented examples for simple sheet-metal design using the proposed method are also presented.