在流体动画中,流体控制是生成可控流体运动的关键技术.为产生视觉逼真、行为可控的流体动画效果,提出一种基于几何特征的流体控制方法.首先通过构建流体形状的时变几何分区,实现对可控流体形状的表达及动态跟踪;在此基础上设计异构控制模型,以增强流体运动控制的灵活性,该模型采用了带约束优化的刚性控制和基于弹簧模型的柔性控制2种方法;最后将异构控制模型与高精度流体物理模型相耦合,生成视觉逼真的可控流体运动效果.实验结果表明,该方法能够在保持流体角色形状的同时产生丰富的流体细节,满足动画师的设计需求.
In fluid animation, fluid control method is one of the most critical techniques for producing controllable fluid behaviors. To provide the fluid animation results with living vision and controllable behavior, we propose a fluid control method based on geometric features. First, we construct a time- varying geometric sub-region model for fluid control which enables us to represent and track the high resolution fluid features effectively. Second, we design a heterogeneous control model to enhance the flexibility of fluid motion control. A rigid control method via constraint optimization and a soft control approach according to spring model is employed in the proposed model. Finally, we couple the heterogeneous control model with the accurate physically-based fluid model to generate controllable visual pleasing results. Experimental results show that our method can produce sufficient liquid details while preserving the character shape which satisfies the requirement of fluid simulation.