中文摘要：

针对MCNP输入文件结构复杂、几何模型描述工作易出错的特点，提出将CSG模型作为三维模型到MCNP几何模型转换的中介以实现自动转换的算法。描述CSG模型数据结构，定义CSG模型的规范化及简化操作，实现并验证CSG模型到MCNP几何模型的自动转换。该方法简化了三维模型到MCNP几何模型转换的复杂度，易于实现三维模型到MCNP几何模型的转换，提高了MCNP输入文件的制作效率。

英文摘要：

MCNP input files have complicated structure and are error-prone in geometry model description. In light of these characters, proposes a method that CSG model is regarded as an interme diary of converting three-dimensional model to MCNP geometry model. Describes the data structure of CSG model, and defines the standardization and simplification of CSG model. Real- izes and verifies the algorithm of converting CSG model to MCNP geometry model. This method simplifies the process of converting three-dimensional model to MCNP geometry model, makes the process of converting more convenient. It improves the efficiency of making MCNP input files remarkably.