The Project

Introduction
Which of the following ball bounces is more interesting?

Most people would pick the second bounce. Squash and stretch is a basic technique to add expressiveness to to movement and motion in animation. It was developed in the golden age of 2D animation and is still used now in 3D animation. However 3D animators usually control the movement of their characters by manipulating a skeleton, and typically do not change the length of the bones. While this preserves accuracy, I believe it also limits the expressiveness of the character.

My research attempts to study classical 2D animation to develop an algorithm that can stretch and squash the bones and joints of motion captured data and make it more "cartoony".

I am also interested in how the expressiveness of the motion might be increased or decreased by the rendering style. Possible problems that might arise might include unfavorable deformations of the character mesh due to weighting that was not intending for such manipulations of the skeleton.

Related Work

1. "Turning to the masters: motion capturing cartoons" - Christoph Bregler, et al. 2002. - Captures motion from 2D cartoons and extracts the affine transformations from the deformations, then it can apply the same deformations to another character.
2. "Simulating cartoon style animation" - Stephen Chenney, et al. 2002. - Created an algorithm for automatic volume-preserving squash and stretch of simple volumes.
3. "Cartoon-style Rendering of Motion from Video" - J.P. Collomosse, et al.
4. "Video Analysis for Cartoon-like Special Effects" - J.P. Collomosse, et al.

Studies

Center of Mass
Length of Bones

Final Results

Final Report - PDF file
Powerpoint Presentation

Movies (Data and Results)

(Movie files removed due to space constraints, but are available upon request)
Rotoscoped Mickey Walk
Motion Capture Walk
Motion Capture Walk with Lowerback Length Altered
Motion Capture Walk with Back Length Altered