保持细节特性的局部误差渐进网格简化算法

针对三维模型简化过程中生成渐进网格时存在局部区域精度与效率平衡优化的问题,提出一种基于局部区域环间法矢夹角变化的半边折叠渐进网格简化算法。首先,获取三维数据点的一环邻近点构成的邻域局部区域受重心度量距离约束的法矢,再获取与一环邻域三角形集合点有交集的三角形集合作为二环邻域区域;然后,以这两个局部区域法矢点乘的值为边折叠的折叠代价,该值越小表示该区域越趋向于平面,应优先简化,否则予以保留;最后,采用三角形内角判断方法来保证简化后网格中三角形的正则度,以减小变形引起的误差。实验结果表明,所提算法在三维模型渐进网格简化中局部细节特性保持和效率上得到较好的平衡,能够满足实际应用的需要。

Local error progressive mesh simplification algorithm for keeping detailed features

To optimize the balance issue of local area accuracy and efficiency in the progressive mesh generation of the 3D model simplification, a new simplification algorithm for the half-edge collapse progressive mesh based on vector angle change between the local area ring was proposed. Firstly, the normal vector was obtained which restricted by center of gravity measurement distance in the local neighborhood area and consisted of points near the first ring of 3D data points. Secondly, the triangle set was selected as the second ring neighborhood area which intersected with the triangle assembly points of the first ring neighborhood area. Then the value multiplied by the two local normal vectors was made as the edge collapse cost. The smaller the value was, the plainer the region was inclined to be and had the priority of simplification, otherwise it would be retained. Finally, the method of angles judgment of a triangle was adopted as the restriction of half-edge collapse to ensure the regular degree of the triangle in simplification mesh and reduce the error caused by the deformation. The experimental results show that the proposed algorithm can better balance the preserving of local detail features and efficiency in the simplification of progressive mesh of 3D model and can meet the needs of practical applications.