B样条曲面自适应拟合算法

针对复杂曲面物体在虚拟环境中的再现问题,依据复杂曲面上提取的已知数据点, 快速反算曲面的控制顶点;由控制顶点、节点矢量确定一条B样条曲面,即真实物体的拟合 曲面.由于提取的数据点存在噪声和摆动,拟合曲面与已知曲面会产生偏差.通过误差判定 条件找到偏差点,根据偏差点、偏差方向及偏差距离计算出曲面更真实的控制顶点;然后重 置相应的控制顶点,达到自动修复拟合曲面的目的.算法在CAD(Computer Aided Design)/C AM(Computer Aided Manufacture)/VR(Virtual Reality)等工程实践中,能够满足对三维物 体造型的不同精度要求.

Auto-adapted fitting algorithm of B-spline surface objects

In view of the reappearance of complex curved surface object in virtua l environment, the control apexes of the surface were fast calculated based on th e known points taken from the curved surface. The control apexes and pitch-poin t vector determined a B-spline curved surface, named the real object′s fitting c urved surface. Because the data points have noise and swings, the fitting curved surface may deviate to the known curved surface at some points. The points wher e the deviation happened could be found by the estimating error condition and the more real control apexes could be calculated according to the deviating points, th e deviation direction and the offset distance, which aimed at automatically repair ing the fitting curved surface. In practice, such as CAD(computer aided design), CAM(computer aided manufacture) and VR(virtual reality), the algorithm can meet the different requests of precision for the three-dimensional body modeling.