The edges in the edge - loop are then changed into faces 选择封闭边,也就是面,挤压生成面。
Single selected vertices which do not belong to selected edges are duplicated and a new edge is created between the two 如果选择边,他从非封闭的边(开放边)复制并且在新建边与原始边间生成面。
The name of a face is consisted of an operator id , an inner id and an array of references of its neighbor faces 每一个面都使用了一个生成面的操作id ,一个操作内部分配的id和一个邻接面表进行命名。