中文摘要：

研究BREP到CSG的转换有重要的理论意义和应用价值，研究该算法的优化技术。观察发现BREP模型的某些特征对BREP→CSG转换有意义，提出利用这些特征优化BREP→CSG转换。首先提出“转换特征”的概念，之后定义单环凸特征、单环凹特征、双环凸特征和双环凹特征4类转换特征；接着讨论如何基于这4类转换特征优化BREP→CSG转换；最后提出转换特征的识别算法一基于扩展属性连接图的特征识别算法。该成果已在自主研发的MCNP（Monte Carlo Neutral Particle）辅助建模软件MCAM（MCNP Automatic Modeling）软件中实现并通过了测试。

英文摘要：

The research on BREP→CSG conversion is of both theoretic and practical interest, the paper studies on its opti mization. It is observed that some features in BREP model are valuable to BREP→CSG conversion. The paper presents the idea of utilizing such features to improve the conversion algorithm. The paper presents conversion feature, and then defines four kinds of conversion feature, single loop protrusion feature, single loop depression feature, double loops protrusion feature, and double loops depression feature. Then discusses how to optimize BREP→CSG conversion by such four features, At last,the paper presents conversion feature recognition algorithm - recognition algorithm based on extended attributed adjacent graphic. The algorithms has been integrated into MCAM that is computer aided modeling tools with our own copyright, and its result is satisfactory.