基于流体动力学的实时角色动画运动特效

在快速的角色动画中,运动模糊技术经常用于产生梦幻般的人物运动效果,从而渲染设计者想要表达的气氛。长期以来,人们常用硬件或软件方法,仅通过简单的图像融合手段实现运动模糊。为了提供高标准的运动特效,基于全局光照的几何方法变得日渐亟需。但是,这样的计算开销对于实时渲染来说往往难以承受。在此,笔者提出了一种新的用于实时运动特效的几何技术。该方法还能结合流体动力学技术,构建一些沿着运动轨迹体而生成的特殊效果。为了避免每帧重复计算,以及为了突破轨迹生成的数据量限制,首先分解运动轨迹,然后引入多步几何渲染技术,实现几何模型的实例化,从而达到重复利用几何资源的目的。在渲染流程中,为了使该方法可以灵活地运用于各种流体效果之中,轨迹追踪的步骤和流体解析的过程是设计成独立的。由于该算法是建立在GPU几何着色的并行环境下,当达到影片质量级别的渲染效果时,它依然能够保证极高的计算效率,最终实现包括运动模糊等特效在内的场景实时渲染。

Hydrodynamics-based Real-time Motion Effects in Character Animation

In fast character animations,motion-blur techniques are always employed for fantastic motion effects,thus expressing the desired atmosphere.During longtime work,it is popular to use hardware or software methods to achieve motion-blur effects through simply image blending.To supply high-standard effects,geometric methods based on global illumination were engaged.However,it could be such a burden of computation for real-time rendering.In this work,a new geometric method was proposed aiming to solve the computational efforts.Nevertheless,some special effects along the motion track were generated though the combination of the hydrodynamics.In order to avoid repeated computation at each frame,as well as break the limitation of trajectory generation,the trajectory was decomposed and a multi-pass geometric rendering technique was enforced to realize instancing for resource reuse.In the rendering pipeline,trajectory tracing and fluid solution were separated to match different fluid effects flexibly.Since the algorithm is based on the environment of parallel geometric shading on GPU,finally,with the rendering quality of cinematic-level achieved,a reasonable cost is maintained to archive real time rendering including the motion blur effect.