Objects that move in response to the actions of a main character often make an important contribution to the visual richness of an animated scene. We use the term "secondary motion" to refer to passive motions generated in response to the movements of characters and other objects or environmental forces. Secondary motions aren't normally the mail focus of an animated scene, yet their absence can distract or disturb the viewer, destroying the illusion of reality created by the scene. We describe how to generate secondary motion by coupling physically based simulations of passive objects to actively controlled characters.

翻译：响应主要角色动作而运动的物体，通常为动画场景的视觉丰富性做出重要贡献。我们使用术语“辅助运动”来指代因角色及其他物体运动或环境力作用而产生的被动运动。辅助运动通常不是动画场景的主要焦点，但缺失这类运动可能会分散或干扰观看者，破坏场景营造的真实感。本文描述了如何通过将基于物理的被动物体模拟与主动控制角色耦合，来生成辅助运动。