( 4 ) the paper proposes a new data structure especially for representing three - dimension objects called half - facet data structure , which provides a firm foundation for further research on modeling of irregular objects . in this paper , the connections among all nodes are given and four methods of transforming half - edge data structure into half - face data structure are presented . these methods are facet cutting method , particulates contracting method , facets enveloping method and enveloping objects method ( 4 )针对实体的三维特性，提出了一种新的描述三维实体的数据结构? ?半面数据结构，论文分析了半面数据结构中各节点之间的相互关系，并提出了半边结构转化为半面结构的方法，分别称为边界切割法、微粒收缩法、边界包围法和包围边界法。
