平面图形在NURBS曲面上的映射

Graphic mapping on NURBS surface based on knot vector matching

针对现有曲面图形映射方法实用性不强的缺陷,提出了一种NURBS曲面图形映射方法。基于曲面外形设计或选取适当的平面图形,求出平面图形在坐标平面内的极限位置,根据曲面上映射图形的位置和大小对NURBS曲面的节点向量和首末参数进行调整,将平面图形嵌入NURBS曲面参数域的相应位置,利用NURBS理论将平面图形从曲面参数域映射到曲面。验证实例表明,算法原理简单、性能稳定,具有较强的适应性和实用性。

Aiming at the poor practicability of existing surface graphic mapping methods,A new graphic mapping technique on a NURBS surface is presented.Based on the shape of the surface,a planar graph is designed or selected firstly,the extreme positions of the planar graph are then determined.According to the location and size of the final mapping graph on the NURBS surface,the knot vectors and limit parameters of the surface are modified to match the planar graph,then all the elements in the planar graph are inserted into the parameter domain of the surface.The mapping graph on surface is achieved by NURBS theory. The examples show that the proposed method is simple and stable and it has stronger adaptability and practicability.