基于特征的复杂曲面反求建模技术研究

几何建模技术是先进制造技术的基础，反求工程是建立产品几何模型的重要手段，复杂曲面几何模型的重建是反求工程研究的重点内容。系统研究了基于实物的复杂曲面几何形状反求建模技术。提出了一种基于特征的复杂曲面几何建模方法，它包括四个主要步骤：首先，对数字化数据进行必要的处理，并建立数字化点之间的拓扑关系；然后，利用这些拓扑关系，提取曲面的几何特征，并依据这些特征对复杂曲面进行分块处理；接着，对每块进行基于特征的曲面构造和数据压缩；最后，将各块拼接形成整体光滑的曲面。

FEATURE - BASED SURFACE MODELING OF COMPLEX SURFACE IN REVERSE ENGINEERING

Geometric model is one of the foundations of advanced manufacturing technology. And, reverse engineering (RE) is an important aspect for geometric modeling of products, especially for products with complex surface. The technique of surface modeling of complex surface in RE is sutdied systematically. A feature-based scheme on surface modeling is presented. In this scheme, there include 4 steps. Firstly, the digital data is pre-processed so that noise in it is filtered and topological relations between points are built up. In the second step, shape features are extracted from the digital data, and the surface is divided into several blocks according features extracted. And in the following step, surface models are reconstructed for every block. Finally, sub - surface models in relation to blocks are merged to generate an overall smooth model.