3 ) when computing the resultant force of each interior spring point , farc andffairare multiplied by a coefficient k . thus , abnormal case will be avoided . 4 ) smoothing between patches is performed 通過(guò)對(duì)經(jīng)過(guò)至少兩次catmull - clark子剖分后的網(wǎng)格應(yīng)用pccm算法,它生成了大片、光滑拼接的雙三次b樣條曲面。