中文摘要：

三维模型表面区域分割技术在形状分析，尤其是局部形状分析中具有重要作用，传统的表面分割方法主要针对网格模型，而机械工程巾的CAD模型通常用B—rep表达．提出一种B-rep形式的CAD模型表面区域分割方法，将模型表面划分为局部凸区域、凹区域和平区域的组合，并使得分割后的区域数量最少．为提高计算效率，提出一种二步法：首先在模型面的局部凸凹性分析的基础上，快速地将模型表面分割成初始的凸区域、凹区域和平区域；然后通过区域合并的方法对分割后的区域进行组合优化，得到一个最优的分割结果．实验结果证明，该方法能有效地分割模型的表面区域．

英文摘要：

Surface region decomposition of 3D models is important for shape analysis, especially local shape analysis. Traditional region decomposition methods are mostly based on mesh models not general CAD models in mechanical engineering. So, a surface region decomposition method is proposed for CAD models with boundary representations, with which the surface boundary of a solid model is divided into local convex, concave and planar regions with the minimal number. To achieve high computation efficiency, a two-pass decomposition approach is used. First, based on the classification of faces according to their local convexity, a surface boundary is initially divided into convex, concave and planar regions. Then, the decomposed regions are recursively combined to form the optimal region decomposition. Experimental results show that this approach can effectively decompose the surface boundary of CAD models.