基于动态位置约束的布料变形方法

在服装动画中,基于物理的方法通常可以产生较好的动画效果。但对于特定区域,如紧贴人体的服装区域等,使用物理方法驱动其变形时,通常需要增大服装与人体面之间的摩擦力,以保证二者相对正确的位置关系。而过大的作用力会引入数值计算问题,从而降低系统稳定性。针对此问题,提出一种动态位置约束的布料变形方法。首先建立服装顶点与人体皮肤面之间的映射关系;其次,基于人体皮肤变形前与变形后的数据求解出仿射变换,并将仿射变换应用到变形前的服装数据上,以求得服装相对人体面的正确位置及运动;最后,通过实验验证了方法的有效性。方法不仅可以对服装指定区域实施持续不变的位置约束,也可以在动画过程中对服装整体或局部动态施加或者解除约束,与物理方法结合使用,能够保持动画系统的动力学特性。

Cloth Animation Based on Dynamic Position Constraint

Physically-based methods are usually used to simulate clothing,with which fine results can be generated.However,to some specific cloth faces,such as regions close to human body,friction between cloth and human have to be increased to ensure realistic animation results.That will result in poor numerical calculation and reduce the stability of the system.A dynamic position constraint method was proposed.First,the nearest neighboring relations between cloth and human body were established.Second,the affine transformation based on the deformation of human body was computed,which was applied to compute new position and motion of the deformed cloth.Finally,some experiments were conducted and the analysis and evaluation were given.The results show that the position constraint can be dynamically imposed or removed.Additionally,it can be combined with physical method to simulate clothing animation,which can maintain the dynamics of the system.