| Reverse engineering is the method which takes the design methodology as the instruction, with the modern theory, method and technology as the foundation, uses all sorts of professional engineering design experience, knowledge and innovative thinking, for existing product to dissect and deepening and re-invention. This is the generalized definitions. Another way of saying, reverse engineering is the re-designing of the existing reverse, and the re-creation is the soul of reverse engineering design methods.In the treatment process of reverse engineering, the initial point cloud data which comes from the scanner is messy and contains a lot of redundant information and noise points. It makes the scale of the point cloud data very huge. As a result, the huge scale caused great difficulties in the curve fitting and surface reconstruction based on the point cloud data. Not only the amount of calculation is huge, but also the noise points causes great influence on reconstructing effect. So the result of reconstruction is difficult to performance the surface shape of the real model. Therefore, this paper focuses on the research of point cloud data processing work, including the point cloud data of layering, sort, curtailing of point cloud data. After completing the pretreatment of point cloud, the number of point cloud has greatly reduced after simplified. We can use these data for next treatment just like curve fitting and surface reconstruction.This paper uses Visual Studio 2005 development tools, integrates Direct3D with MFC. completes D3D initialization work in document view model, and uses Microsoft's Direct SDK development tool to complete the point cloud data display and reconstruction work. It has broken down the rule of OpenGL in CAD auxiliary design field, and is a bold attempt in the use of new technologies.In this paper, a set of non-contact equipment is used for measuring seat point cloud data. Its principle is to use linear laser to measure the surface of the model. After projection imaging use the light at the physical surface offset to calculate model each point of distribution, height distribution. Then measure in a fixed one-dimensional, and get the 3d data information of surface by scanning. This paper used section plane approach to layer the original point cloud data.The cloud data, in fact also contains a large amount of redundant information should generally be simplified. This paper puts forward a algorithm of K neighborhood Combined with curvature change and another algorithm based on line, secondary curve and three times Beizer curve. Then analyses the efficiency and effectiveness of the two algorithms.The end result of this paper is to generate a.X model file of proprietary Direct3D system, and that file contains not only the information of vertex, but also the index information of the triangle vertices of each surface that be constituted vertices, so we need for the mesh processing of point cloud data, and the surface reconstruction. This paper introduces some commonly surface reconfigurable algorithms, including Delaunay triangulation, uniform B-spline reconstruction, non-uniform rational B-spline reconstruction (NURBS), and proposes a method of layers triangulation, according to layer arrangement and the features of transversal cloud data and point cloud data. Finally, exports the information of mesh and vertex that been gotten by triangulated to. The.X model file and that can make prepare for parameter modification automatically. |
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