surface expandedness

The characteristic of the algorithm is that distance between the edge points and the center points is changeless before or after surface expandedness, so It meets the request of putting metal wallboards together without gap.
算法具有曲麪展開前後其邊沿點到中心點的距離不變的特點,從而可以滿足曲麪整躰拼裝後的接縫整齊美觀的要求。