科研之友
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摘要
We consider the problem of computing a parting line for a mold for a complex mesh model, given a parting direction, and the related problem of removing small undercuts, either preexisting, or resulting from the parting line. Existing parting line algorithms are unsuitable for use with complex meshes: the faceted nature of such models leads to a parting line which zig-zags or wanders across the surface undesirably. Our method computes a smooth parting line which runs through a band of triangles whose normals are approximately perpendicular to the parting direction. We generate a skeleton of this triangle band to find its distinct topological cycles, and to decompose it into simple pieces. After selecting paths making a good cycle, we generate a final smooth parting line by iteratively improving the geometry of this cycle. Compliance in the physical material, and/or modifications to eliminate minor undercuts ensure that such a parting line is practically useful. Note to Practitioners-Molding is the process of manufacturing a part by shaping a pliable raw material, such as molten plastic or metal, using a rigid mold. The material hardens and sets inside the mold, adopting its shape. To remove the part from the mold without destroying the mold, the mold must be made of multiple pieces. In the simplest case, a two-part mold is used, and these parts are separated in opposite directions. The curves on the surface of the part where the pieces of the mold meet are called "parting lines." For a manufacturing perspective, a smooth parting line is more applicable than a theoretically correct parting line. We give a novel method to compute such a parting line in this paper.
- 出版日期2009-7
- 单位上海交通大学
