The Key Technology Of Reverse Engineering, Cad Modeling Study

With the rapid progress of computer technology, CAD / CAM technology has become an important tool used by product designers on research and development. Three-dimensional modeling technology which has been widely used in product design, mold manufacturing, automated processing and other aspects. In product development and manufacturing process, the designer should be based on the known requirements or design concepts, and designs the product drawings or simulates the models of the products directly. Then after a program evaluation, the final product produced. However, lots of designers get just a sample in most cases, they need to imitation of surveying and mapping based on the sample or to improve its performance and appearance. This requires the designer use the theory and method of Reverse Engineering to put the sample into a CAD model, to achieve the ultimate goal. Reverse Engineering could improve the technical level, shorten the production cycle to improve the productivity and market competitiveness when it has been applied to actual production. So the study of reverse engineering was a high degree of many scholars at home and abroad concern.Reverse Engineering relates the theory and method of many subjects,such as system engineering, production design methodologies, computer-aided manufacturing and so on. There are a series of key technologies on Reverse Engineering CAD modeling. This paper focuses on four aspects of the series of key technologies to discuss and research which are based on the results of the previous research by experts and scholars. This paper completes the work as follows:The previous processing of 3D scattered data points: The previous processing of 3D scattered data points has problems previously, this paper presents a fast approach, such as the use of average angle and average distance processed on bad points, which can avoid the shortcomings of remove the bad points by raditional manual methods such as visual inspection method and make the identification and removal of bad points more intelligent, and use the matlab programming algorithm to achieve it.Mesh generation of 3D scattered data points: Today, the interchangeability of the CAD/CAM system and the B-spline curves/surfaces is becoming better and better, this paper has put forward the three uniform B-spline curve on the surface reconstruction method. For those who used B-spline curve, you need to point topology data for the four-domain structure. Accordingly, this paper meshes the 3D scattered data points into triangular grid first and then convertes them to four-domain grid .This method meets the requirements of the topological frame of the surface reconstruction, and makes the reconstruction more convenient.Surface reconstruction of 3D scattered data points: By studying the relevant literatures, this paper puts forward a counter-balance use of three uniform B-spline curve to fit B-spline curves and surfaces of the method of interpolation to speed up the reconstruction process, and to ensure that the reconstruction of the curve after reaching a row, and the surface reconstruction to achieve continuous.Smoothing processing after surface reconstruction: No matter what method of reconstruction of curves and surfaces can not fully meet the product requirements of form of smoothing. In order to make products more attractive appearance, this paper put forward by the energy in the previous theory on the basis of a curvature are based on smoothing of the energy method. This paper describes the principles and steps of the new algorithm in detail, and examples are given to verify the new algorithm.