裁剪曲面有效离散点的参数识别方法及其应用

Recognition of Discrete Points on Trimmed Surface Based on the Parameter Plane and Application

针对目前常用商业CAD系统在复杂参数曲面有效离散方面所存在的不足,结合实际工程设计与应用方面的需要,提出了一种基于二维参数域的裁剪曲面有效离散点的识别方法。该方法将曲面离散点的有效性判定从复杂的三维空间巧妙地转换到曲面相应的二维参数定义域,通过对离散点相应的参数是否位于裁剪曲面参数定义域的判定,解决了复杂曲面大量离散点的快速区分和有效识别的问题。计算结果和应用实例都显示,该方法是正确有效的。

A recognition method of discrete points on trimmed surface is presented,which is based on the plane domain of surface parameter.The approach changes the recognition from the complex 3D space to the simple parameter plane artfully.The discrete point of a full NURBS is on the trimmed surface only when its NURBS parameters are in the domain of trimmed surface.The method solves the problem of the recognition for large numbers of discrete points.In CAD and CAM,it is a good supplement for the current geometric modeling systems such as CATIA and UG.Some examples in reverse engineering are also presented in the paper.