| Summary: | 博士 === 國立中央大學 === 機械工程研究所 === 98 === Triangle mesh is a common geometric model and is widely used in the field of engineering, especially in the product development process which involves forward engineering, reverse engineering and rapid prototyping. In reverse engineering, for rxample, the measured data is always saved as triangle meshes. Feature segmentation and surface reconstruction are generally implemented on the base of triangle meshes. Moreover, the input data of a rapid prototyping process is still triangle meshes. In this study, three important problems on triangle meshes wre investigated and appropriate algorithms are developed to deal wth these problems. Specifically, the three problems addressed are as follows:
(1) Repairing triangle meshes: it is an approach to detect and eliminate erroneous facets on triangle meshes. Five types of erroneous facets are identified, namely, degenerate, non-manifold vertices, self-intersection, incomplete connection and inconsistent plane normal. Algorithms for dealing with all these erroneous facets are developed.
(2) Feature segmentation algorithms for quadratic surfaces: it is composed of two steps. First, a region growing is developed to search for a small area near a seed point to determine the feature type, which can be a plane, a spherical surface, a cylindrical surface or a conical surface. Second, a re-growing procedure is employed to search for the points of the same feature type.
(3) Partial mesh replacement: it is composed of three steps: cutting path computation, mesh segmentation and mesh stitching. The cutting path computation is employed to evaluate the intersecting points of all meshes lying under the projection of the boundary curve. Mesh segmentation is employed to divide the original meshes into two parts: preserved and replaced meshes. Mesh stitching is finally employed to sew the boundaries of the preserved and new meshes.
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