关键词: 半空间构造实体几何(CSG)模型, 模型转换, 模型分解, MCNP程序

Abstract: The modeling for Monte Carlo N Particle Transport Code Program (MCNP) is a difficult problem.To solve the problem,a novel algorithm was presented to transform the BRep model to the half space Constructive Solid Geometry (CSG) model.The concept of the half space transition element was defined,and the feature recognition method for BRep model was presented based on this concept.According to the feature recognition method,the decomposition surfaces were constructed to decompose BRep model into the several half space transition elements.In addition,the assistant surfaces were added to avoid the half space description ambiguity.The ability and the efficiency of the algorithm was tested by several model transition tasks,and the result proved that the efficiency of MCNP input file production had been improved.

Key words: half-space constructive solid geometry model, model conversion, model decomposition, Monte Carlo N particle transport code program