面向MCNP程序的三维模型前处理技术研究

提出了一种用于MCNP计算程序的三维模型前处理技术，并给出了CAD模型识别与简化、空腔生成以及CAD模型向半空间CSG模型转换等关键算法.设计并开发了用于MCNP计算程序的三维模型前处理系统，用于CAD模型至MCNP半空间CSG模型的快速转换.最后通过实例对软件系统进行了验证，结果表明文中所提出的方法能够快速实现复杂CAD模型至MCNP半空间CSG模型的转换，为MCNP计算程序提供了高效的三维模型处理系统，提高了MCNP程序输入文件的制作效率. 

Study on 3D Model Pretreatment Method for MCNP Calculation

A 3D model pretreatment method was proposed for MCNP calculation program, including model recognition and simplification algorithm, the cavity generation algorithm, and the efficient conversion algorithm from CAD models to half space CSG models. And a 3D model pretreatment system was developed for MCNP calculation program to make the CAD model be transformed into half space CSG model rapidly. Finally a practical example was arranged to validate the developed system. The results show that, the proposed method can quickly transform complex CAD models into half space CSG models, providing an efficient 3D model pretreatment system for MCNP calculation program. It can improve the efficiency of the MCNP input file construction.