提出一种针对三维封闭三角网格模型的缺失实体孔洞修复算法,由初始导引点出发,根据几何特征搜索孔洞边界,并以水平集方法扩展边界,获取目标问题区域。基于边界采样和投影方法建立代理曲面,实现了内环三角化细分和三维网格表面的自由变形。通过合并环间区域和引入边缘约束的平滑过程,得到缺失实体孔洞的上缝合面。在此基础上向内扩展,获取孔洞下表面边界轮廓,搜索出上下边界环之间的三角网格区域,并利用同样的方法构建缺失实体孔洞的下缝合面。最终,连接上下缝合面以及两个边界轮廓环之间的三角网格区域得到修复实体。试验制作的样件表明,算法能简化人工交互设计的步骤,生成高质量的修补结果。
An entity hole repairing algorithm for three-dimensional closed triangular mesh is presented. From the input of a set of guide points, the upper boundary ring of the hole is searched according to edge features and the position of the objective point. The boundaries of the objective region are recognized on the basis of expanding rings to both two sides through level set method. By sampling on the two rings, a projection method is used and the surrogate surface is constructed. A refined mesh of the triangulated upper ring can be deformed and smoothed by merging the region between the two rings with imported boundary constraint. Then the upper patching surface is created. The inner boundary ring is identified by an inward expansion of the upper ring, and the lower patching surface is created by using the same method. Finally, the repair entity can be constructed by stitching the upper patching surface, lower patching surface, and the region between the upper ring and lower ring. Experiment shows that the algorithm can minimize the manual interaction steps and generate a high-quality scaffold model.