Progressive LOD and Topology Operation Based on Graph Rotation System
Limin Xia · Zhongguo tiedao kexue · 2007
Current LOD(Level of detail) method can not preserve 2-manifold of models.In this paper two topology operations,CutTunnel and CreateTunnel,are presented.By inputting a vertex set which belongs to an edge track around the tunnel to be cut into CutTunnel operation algorithm,the algorithm deletes all the edges connected to the vertex in vertex set.Thus the tunnel is cut.CreateTunnel operation is the reverse operation of CutTunnel.Based on these,a new progressive framework is presented.In this framework the data structure based on graph rotation system is used to represent meshes.The framework can be divided into two procedures: create LOD procedure and use LOD procedure.Create LOD procedure can change the topology of models,and automatically produce progressive LOD meshes.Use LOD procedure can gradually change the model from one level to another level of LOD.This framework can preserve 2-manifold of models.We test the topology operations,create LOD procedure and use LOD procedure by using the buddhaf model of Stanford University.The result shows that our framework and topology operations work well and the results are satisfying.The model has been preserving 2-manifold during the whole test.