Entity Model Reconstruction Of Planar Contour

With the forming of the buyers' market, the trend of global competition has been intensified much more than before. The ability of developing new product rapidly for manufacturing enterprise already becomes the chief factor, which determines the enterprise's fortune. As an important approach of rapid creative design, Reverse Engineering has got more attention.The research on constraints based structural feature model reconstruction method is a new aspect in reversing engineering, which can be used to reconstruct more reliable model. Modeling in current 3D CAD software such as CATIA,pro/Engineer are mainly based on sketch design. According to the idea of modeling and on the basis of segmenting 3D data with feature design intention, this thesis studies the reconstruction methods of model sketch-based feature such as extruded and rotational features in structural part models. The main contents of this thesis are as follows:1) According to the approximate curvature of each contour point, the feature points are recognized from the point-data; the styles of them are confirmed.2) The unsymmetrical origin-distance approach is adopted to reduce the 2D point-data.3) After confirming the segments types (line or circle) we call that approach as "Sign Error Accumulative Total". The contour is globally constructed through determining the constraints with the neighbor segments.4) Studying and deducing the reconstruction methods of unconstraint beeline segments, unconstraint circle segments, and constraint circle segments.Applying the reverse engineering tools of Pro/ENGINEERING to realize model generation of the rotational entity, extruded entity, and advanced surface of Blend from File.