摘要：This paper proposes an approach to determining pull directions of an undercut region using the visibility map algorithm. A number of pull direction candidates are firstly generated and projected onto a spherical surface using a regular placement algorithm. The normal directions of undercut faces are then extracted and used to eliminate unwanted pull direction candidates. A group of pull directions are finally selected and used to design a side core mechanism in the design of an injection mould. Furthermore, one point at the center of the group is chosen to represent the pull direction of the undercut region.
