中文说明：本代码的运行环境为matlab，通过绘制四条边界曲线，然后根据这四条边界曲线自动生成nurbs曲面，可以通过调整控制点来调整曲面
English Description：
The running environment of this code is matlab. By drawing four boundary curves, and then automatically generating the NURBS surface according to the four boundary curves, the surface can be adjusted by adjusting the control points