基于区域分割与约束逼近的二次曲面重建

从散乱数据中有效地分离出特征与约束是表达原始产品设计意图的关键.基于点的连通性及同一特征曲面数据点估算法矢、曲率的相似性,并在特征曲面拟合误差控制下实现了空间散乱数据二次曲面数据的自动分离;应用二次曲面的几何参数表达建立了二次曲面整体约束逼近的最优化数学模型,将几何约束情况下的二次曲面重建转化为数学模型的求解,使重建的CAD模型可有效再现二次曲面之间的几何约束.工程应用实例表明:该方法稳定可靠,可显著提高反求工程CAD建模效率及重建模型精度.

Quadric surface reconstruction based on segmentation and constrained optimization

Quadric surface was one of the most accepted methods for representing the complex shapes at (industrial) products,due to its natural properties.In raverse engineering, how to extract the valid features and its intrinsic topological constraints from unorganized data is the key to racover the original design intendt.A new algorithm for constrained (reconstruction) of quadric surface from unorganized 3D points was proposed. The method includes two steps. First, based on the adjacent relationship and similarity of normal vector or curvature of points, points distributed on quadric surface were segmented from the measured points-cloud with region growing method under a given error for surface fitting. Second, for multiple surfaces fitting subject to geometric constraints, a general mathematical model was established. By solving the model, the regularities and symmetries applied in product design originally can be represented and used to reconstruct the CAD model. Engineering applications show that the precision and efficiency of remodeling are (improved) remarkably.