Note : the number of control points is different from the original surface and depends on the specified knot spacing or the specified number of control points 注意：控制点的数目是和原来的曲面不同的，它取决于指定的控制点的间距或者指定的控制点的数目。
2.
Its accomplishment is simple and intuitional . the main innovation of this method is that we only need construct a symmetric zonal mesh for each interpolated curve respectively and write appropriate knot spacings for mesh edges . then applying nurcc rules to the initial control polygonal mesh consisting of those symmetric zonal meshes can generate a surface that satisfies interpolation constrains 该方法的主要创新思想是在被插值曲线的控制多边形两侧构造具有简单对称性质的四边形网格，称为对称网格带，但关键还在于对网格边赋予适当的节点距，并对由这些对称网格带组成的初始控制网格应用非均匀有理catmull一clark细分规则，来生成满足插值要求的曲面
