三维封闭三角网格孔洞边界识别算法

针对三维封闭三角网格模型的缺失实体孔洞，提出一种边界识别算法。以手绘曲线作为输入，结合轮廓线法得到目标孔洞的近似边界点集，生成连续的孔洞轮廓线。按照曲线点集并以孔洞轮廓线辅助搜索孔洞的上边界，根据上边界向下搜索得到孔洞的下边界。该算法可用于满足二维流形、可定向及封闭的三角网格模型上孔洞边界的定位，能够简化孔洞边界的定位过程，提高设计系统的易用性。

Hole Boundary Identification Algorithm for 3D Closed Triangle Mesh

An entity hole boundary identification algorithm for 3D closed triangle mesh hole is presented in this paper. The area sounding the hole is selected by a smoothed curve which is dragged by the mouse. By using the dot product between the triangle normal and the viewing direction, the model silhouettes, and a continuous hole silhouette can be obtained. The 3D hole boundaries of the inner surface and the outer surface can be searched according to the curve point set and the hole silhouette. This whole flow is used to simplify the interactive operation for the identification of hole boundaries on the model which is a 2-manifold, oriented, closed and non-simple connected triangle mesh, which can improve the convenience for design system.