View-Dependent Control of Elastic Rod Simulation for 3D Character Animation

Abstract

This paper presents view-dependent control of elastic rod simulation for 3D character animation. Elastic rod simulation is often used in character animation to generate motion of passively deforming body parts such as hair, ear, and whiskers. Our goal is to allow artistic control of the simulation in a view-dependent way, for example to move a hair strand so that it does not hide the eye regardless of the view direction. To achieve this goal, the artist defines several example rest poses of the rod in preparation, each of which is associated with a particular view direction. In run time, the system computes the current rest pose by blending the example rest poses associated with the view directions near the current view direction, and then pulls the pose to the current rest pose. Technical contribution is in the formulation of example-based rod simulation using view direction as an input, and an algorithm to suppress undesirable increase of momentum caused by dynamically changing rest poses.