1990 年 56 巻 3 号 p. 491-496
This paper deals with a processing system for extracting undercut in mold designing. The development of such a system involves the solution of two problems. One is how to extract those parts which may form undercuts-the parts that may be called “potential undercuts” -from the shapes of moldings. The other is how to determine on the optimum direction of withdrawal of moldings. In solving the first problem, we worked out a new method for extracting potential undercuts; this method comprises the determination of three-dimensional convex hull and set operations. The approach to the second problem was the use of the simplex method, one of the nonlinear optimization methods, to find the optimum direction of withdrawal of moldings. A case study was then conducted to verify the usefulness of the processing system thus developed.