四边形网格的去边细分方法

提出一种四边形网格细分算法：每细分一次四边形网格，其数目增加为原来的两倍，细分二次结果相当于一次二分细分和一个旋转．该算法采用三次B样条张量积的形式，其生成曲面在规则点具有C^2连续性，在非规则点具有C^1连续性．由于该细分算法对网格几何操作简单，所得网格数据量增长相对缓慢，适合于3D图像重构及网络传输等应用领域。

Edge Flipping Subdivision Scheme for Quadrilateral Meshes

A new stationary subdivision scheme is presented for quadrilateral meshes. In contrast to the usual dyadic splitting operation, the number of quadrilaterals increases in every step by a factor of 2. Applying the subdivision twice is equivalent to a dyadic subdivision and a rotation. The presented algorithm is derived from tensor product of cubic B-splines, so the resulting surface is C2 continuous for regular vertices (with valence 4) and C1 continuous for extraordinary vertices (with valence other than 4). The simplicity in geometric operation and the slow topological refinement make the subdivision scheme more suitable for many applications, such as 3D image reconstruction and network transmission.