Simplification Of Triangular Meshes And Iso-surface Extraction

In this dissertation, three-dimensional complex triangular meshes have been investigated. The paper mainly discusses the methods of model simplification, normal mesh generation and iso-surface extraction. Firstly the paper introduces the basic concepts of triangular meshes, then surveys the model simplification and level-of-detail representation.The main contributions of this paper include:1. An edge-collapse algorithm based on subdivision scheme is proposed. In this algorithm, we use the idea of subdivision surface to locate the new vertex when an edge is collapsed. By analyzing the mechanism of the edge-collapse, we give out a sufficient condition keeping manifold. The result shows that it guarantees higher quality and topological integrity of triangular meshes.2. An algorithm to be able to process very large scales of meshes is proposed. This algorithm uses the method of vertex clustering, employs a quadric error to generate the new vertex of clustering, and makes use of octree to divide the space. Moreover, it can keep the normal direction of triangular faces.3. A modified algorithm of normal meshes is proposed. It can process the model with boundaries, and has not used the parameterization. In order to optimize the distribution and the shape of triangles, a Laplacian smooth procedure has been employed.4. A quick algorithm of iso-surface extraction based on region growing is proposed. This algorithm employs an optimized searching strategy to speed up boundary voxels' searching and iso-surface extraction. The experiment results show that the algorithm is much quicker than the traditional marching cube algorithm.