Information Extraction And Processing From Digital Body And Garment Models

With the development of the 3D garment modeling and the virtual reality, 3D garment CAD as a new clothing design technique has been applied widely. Now, the garment CAD includes the garment style design, the pattern design, the industrial design, the fabric design, the completed clothing fitting, and so on. Bases on the 3D garment CAD's characteristics, this thesis does the research on the information extraction and processing from digital body and garment models, and provides the theoretical foundation for the 3D garment modeling, the digital clothing style design and the 3D garment diversity of various shapes.According to the theory of 3D garment CAD, this thesis uses the knowledge of computer graphics and other related technologies to do the research on the approximate shortest path construction, the interactive segmentation and the parameterization of triangular meshes, and then we achieve the size information extraction from digital body and garment models and design the fitted garment pieces. All the details are as follows:(1) We have the comprehensive analysis on the research status about the 3D digital garment editing, and point out its important research significance and wide application prospects.(2) We have the research on the pick-up operation on meshes, which is used frequently on the 3D garment design and virtual clothing try on system. Here we translate the ray into the model space to do the intersection based on the used matrix to get the pick-up information from 3D garment models.(3) We present a new algorithm for computing the approximate shortest path between any two vertices on triangular meshes. The algorithm first defines a cutting plane which intersects with the mesh. The initial path on the mesh surface is obtained by connecting intersection points. And then it improves the path algorithm for correcting the point on the edge or the vertex to compute the approximate shortest path. The improved path algorithm is applied for the size information extraction of 3D body models which can achieve good measurement results.(4) We propose a new algorithm for interactive mesh segmentation based on the feature line. The algorithm first computes the discrete curvature of triangular mesh vertices which adopt the triangular centroid weights and the vertex normal vector formula weighted by the area and angle of neighboring triangles, feature points are defined as the curvature extrema in the principal direction. Then it searches valleys and ridges which consist of feature lines by the group connecting along the mesh edge. Finally it uses the seed filling algorithm in the feature region, a complex triangle mesh with arbitrary topology can be efficiently segmented into several required patches and each patch is homeomorphic to a disk. The results of segmentation could facilitate the further processing of meshes.(5) We provide an improved stretch-minimizing mesh parameterization algorithm. It gives the general expression of the vertex stretch in planar parameterization and then constructs a new formula which can effectively reduce the parameterization stretch. The algorithm is then applied to design the fitted garment pieces which can achieve good results.In the end of this paper, it summarizes the current work and gives the development prospects of this research.