Acceleration Skinning: Kinematics-Driven Cartoon Effects for Articulated Characters

Niranjan Kalyasundaram, Damien Rohmer, Victor Zordan

Keywords: rigging, skinning, linear blend skinning, deformer, secondary motion, cartoon effects

TL;DR: Introduces an extension to standard skinning that employs animation acceleration to produce cartoon effects during rig skinning

Abstract:

Cartoon effects described in animation principles are key to adding fluidity and style to animated characters.
This paper extends the existing framework of Velocity Skinning to use skeletal acceleration, in addition to velocity, for cartoon-style effects on rigged characters. This Acceleration Skinning is able to produce a variety of cartoon effects from highly efficient closed-form deformers while remaining compatible with standard production pipelines for rigged characters. This paper showcases the introduction of the framework along with providing applications through three new deformers. Specifically, a followthrough effect is obtained from the combination of skeletal acceleration and velocity. Also, centrifugal stretch and centrifugal lift effects are introduced using rotational acceleration to model radial stretching and lifting effects. The paper also explores the application of effect-specific time filtering when combining deformations together allow for more stylization and artist control over the results.