设P(m,n)是初始控制点列，即原曲面的点（m行n列）。Q(m,n)是一次细分后得到的曲面的控制节点。

此函数采用Catmull-Clark细分曲面算法，对双三次B样条曲面细分,即m=n=4。

利用我们在13章第四节学过的知识，有公式MQM =SMPM S ,其中M，S可由课件知

构造初始控制点列（p1,p2)，其中p1是P的行坐标，p2是P的列坐标

-Let P (m, n) is the initial control point of the column, i.e. the original surface of the point (m rows n columns). Q (m, n) is the control node of the surfaces one after subdivision. This function takes a Catmull-Clark subdivision surface algorithm, the bi-cubic B-spline surface subdivision, ie m = n = 4. Using knowledge in Chapter 13, section IV, formula MQM, ' = SMPM' S' , wherein M, S by courseware known structure the initial control point of the column (p1, p2), where p1 is the row coordinate of P, p2 column coordinates of P