卡通动画雨模型

A Rain Model for Cartoon Animation

给出了一个能自动生成卡通风格的小雨和大雨效果的计算机模型.首先介绍如何从手工绘制的卡通雨动画序列中分析并提取雨滴降落轨迹的静态结构与动态结构,以此为基础生成它们的骨架模型.在小雨模型中,只采用单层骨架,在大雨模型中,则采用多层雨滴以表示降雨的深度感,并添加溅落到地面的雨滴,以进一步强调效果.由于在模型中采用了随机分量控制,因而在生成的下雨效果中避免了在手工绘制动画里重复使用周期序列画面带来的机械感.在手工绘制动画中若想改变下雨轨迹的方向和速度,以烘托动画气氛,则需要分别绘制不同的下雨动画序列,工作量很大.采用该模型只需通过控制少量几个参数便可以十分容易地改变下雨的方向与速度.该模型不仅能再现传统二维卡通下雨的效果,而且能在三维空间生成卡通风格的下雨动画.

A computer model capable of generating stylized light rain and heavy rain for cartoon animation is presented. How to analyze and extract the static and dynamic structures associated with trajectories of raindrops from hand-drawn cartoon series is shown at first. Based upon those structures, how to generate their skeletons and control dynamic behaviors of those skeletons is also shown. The single pass is used in the light rain model and the multiple passes are used in the heavy rain model, and in the later case the effects is enhanced by animating a cycle of drops hitting the ground. Due to the stochastic control mechanism used in the model, the resultant effects avoid the mechanical look that may cause by using repetitive cycles in hand drawn animation. To suggest mood, animators have to draw different series with different timing and orientation of raindrops, while by varying a few parameters the model can achieve the same results with great ease. The method is also able to generate both 2D and 3D cartoon raindrops for animation.