用于非均匀有理B样条曲面裁剪的扫描线算法  

Scan line algorithm for NURBS surface trimming

作　　者：方顾[1] 李际军[1] 

机构地区：[1]浙江大学计算机科学与技术学院,浙江杭州310027

出　　处：《计算机集成制造系统》2007年第10期2060-2063,2070,共5页Computer Integrated Manufacturing Systems

基　　金：国家863计划资助项目(2006AA04Z106);浙江省科技计划重点资助项目(2004C21G2010027);宁波市科技计划资助项目(2005D100053)。~~

摘　　要：提出一种用于非均匀有理B样条曲面裁剪的算法。首先在非均匀有理B样条曲面的参数域中定义曲面的裁剪曲线,然后自上而下地分析曲面参数域中的每一条U(或V)向线段(扫描线),通过这些扫描线与裁剪曲线的相交关系来判定曲面的裁剪域,再将其映射到三维空间中,从而显示出裁剪操作的结果。由于可以通过定义扫描移动最小步距值来控制曲面裁剪操作的精度,该算法适用于各种精度需求的裁剪操作场合。此外,也可以根据需要对扫描进行定位操作来实现各种裁剪特效。An algorithm for Non-uniform Rational B-Spline （NURBS） surface trimming was proposed. The trimming-curves were firstly defined in the NURBS surface parameter domain. Then the U （or V） direction scan lines were analyzed one by one in the parameter domain. The trimming domain of the surface, which would be mapped to 3D space for the trimming result, was decided according to the intersections of scan lines and trimming curves. This algorithm was suitable for diversified precision trimming needs because the＇smallest scan step-length could be adapted to control precision of surface trimming. Moreover, many special-effects could also be implemented by locating current scan line to a special position according to different requirements.

关 键 词：曲面裁剪 几何造型 复合非均匀有理B样条曲面 裁剪曲线 

分 类 号：TP391.72[自动化与计算机技术—计算机应用技术]