三维虚拟植物中非流形结构的紧凑表达

Compact Expression of Non-manifold Structure for 3D Virtual Plant

构建紧凑的网格数据结构是高效交互式操控虚拟植物的重要前提.根据虚拟植物的拓扑结构特点,提出一种适用于虚拟植物中非流形结构的紧凑表达方法.在半边结构的基础上,利用顶点的外出半边获得与该半边相对应的反向半边,将该半边和反向半边分别存放在对方的反向半边列表中;通过反向半边列表判别虚拟植物拓扑结构的类型,实现拓扑信息查询.对虚拟植物实例进行三角网格的数据结构重建的实验结果表明,与传统半边和基于半边的数据结构相比,该方法所需内存空间减少,且更便于几何和拓扑信息处理.

In order to efficiently manipulate the geometry and topology information of virtual plants,which includes boundary and non-manifold edges,a more compact representation of the topology information was proposed.The proposed data structure makes full use of the implicit representations among vertices,half-edges and triangular faces.The index of the face and the implied number of the half-edge are encoded into an unsigned long integer based on half-edge data structure.The position information and an outgoing half-edge are set as attributes in the vertex object,the vertex pointer and the opposite half-edge list are set as attributes in the triangular face object.The topology information of the mesh can be efficiently queried and processed by decoding the half-edges in mapping table.The test of the topological reconstruction for virtual plant was done.Compared with other half-edge data structures,the memory footprint of the proposed data structure is reduced.