Streamlined Approach Based On Point Cloud Of The Bsp Tree

The definition of Reverse Engineering (RE) is that given a three dimensional real model, constructing an integrated Computer Aided Designed model which can be. The digital equipment can be used to acquire the discrete data also called point data. Therefore, RE is divided into four processes: data acquisition, data preprocessing, surface fitting and model construction. The data is so large that is not only burdens the system, but also reduces the efficiency of the later processes. So it is very important to simplify the original data.This paper mainly studies the simplification methods. At first, this paper introduces how to estimate the surface geometric characteristics, such as curvature and normal vector, according to analyze the space position relation among the point cloud data. In this part, a new method based on Wu's work is proposed to adjust the direction of the normal vectors.The work in this paper is that improving the hierarchical clustering algorithm on the way to choose the partition plane and the representative sample, and to avoid the problem that near surface and under-sampling.1. Using the method, which is applicable to local surface, to computing the maximum variation of the surface, some error may occur. Considering the different points having different distances to the center, this can bring some influences. This paper uses weighting coefficient to remove the influences. 2. If the representative sample is the center of a cell, then because it is not the original point, some unexpected triangles may protrude from and concave into surface. This study chooses the original point that is the closest to the center, and selecting the closest point can effectively reduce the probability of producing errors.3. The near surface can cause non-manifold. The paper is based on Jong's and Lee's algorithm, and proposes a method to modify the near surface problem. The method contains two parts: auxiliary point is used to detect the near surface in the cell containing more than three points, and the cell containing less than three points is subdivided compulsively.4 Unexpected holes during reconstruction resulting from under-sampling, due to insufficient information about for neighboring points in the local region. To...