中文摘要：

针对CAD模型通常包含大量几何特征，而某些特征会制约高质量网格生成的问题，提出一套实现组合曲面模型的自动特征简化和高质量网格生成的算法．首先引入离散曲面B-rep和虚面等概念，扩展B-rep的适用能力；随后基于扩展B-rep自动识别短边、窄面、邻近和不光滑边界等4类曲面特征；其中短边利用曲线合并来消除，后3类特征则通过曲面合并来消除．由于曲面合并形成的虚面缺乏连续的参数表达，可利用其离散模型生成高质量曲面网格；虚面内部网格点被反映射回连续曲面，以保证最终网格模型的几何精度．最后通过若干特征简化和网格生成实例验证了文中算法的有效性和实用性．

英文摘要：

Geometric features contained in an original CAD model might prevent the generation of a high-quality surface mesh on the model. An automatic approach is proposed to remove the features defined on the composite parametric surface model, followed with an enhanced surface mesh generation seheme for the defeatured surfaces. An extended B-rep that combines the concepts of discretized models and virtual topologies is employed to provide fundamental geometric services for the proposed approach. Four kinds of surface features, i.e. short edges, tiny surfaces, proximities and unsrnoothed surface boundaries, are recognized, among which short edges are suppressed by edge clustering, and the other features are suppressed by surface clustering. Virtual surfaces formed by surface clustering have no continuous parametric forms and have to be meshed on their discretized models. Subsequently, the interior mesh nodes on virtual faces are mapped back to the continuous surface to achieve a higher geometric fidelity. Some numerical experiments are finally presented to demonstrate the effectiw and validity of theproposed approach.