纱线仿真模型的建立

Establishment of the Yarn Simulation Model

根据纱线的形态结构和性质,分别用虚拟现实技术VRML及非均匀有理B样条(NURBS)曲面算法对纱线外观进行建模。VRML方法是将纱线看作主体骨架和加捻造成的凹凸两个组成部分,根据骨架建模思想实现了纱线的真实感仿真。NURBS曲面算法结合纱线的加捻特征,将纱线截面做平移、旋转等操作,对得到的控制顶点进行拟合,构建出了纱线外观模型。实验结果表明,这两种方法都实现了纱线外观的仿真效果,但采用NURBS曲面算法建立的纱线外观曲面比通过VRML方法建立的更为平滑,达到了预期的效果。

According to the shape structure and properties of the yarn,respectively uses the Virtual Reality Modeling Language（VRML） and the Non-Uniform Rational B-Splines（NURBS） to model the appearance of the yarn.VRML think that the yarn is composed of two parts that is the main skeleton and the concave and protruding surface caused by twist.According to the skeleton model,VRML realize the realistic simulation of the yarn.The algorithm of NURBS considers the features of twisting the yarn,then,do some operations to the yarn＇s cross-section,such as translation,rotation and so on,to simulate the yarn appearance model by fiting the controling vertex.The results showed that： both methods achieved the simulation of yarn appearance,but the yarn appearance surface established by the NURBS algorithm was more smoothly than the VRML,and achieved the expected effect.