cartoon motion and deformation of skeletons ting ting wu advisor – nancy pollard

Cartoon Motion and Deformation of Skeletons

Ting Ting WuAdvisor – Nancy Pollard

Background/MotivationWhich looks more interesting?

Which looks more interesting?

Background/Motivation

Most people pick this one

- Anticipation and Follow-through- Stretch and Squash

2 Ways to Apply Stretch and Squash

- posture

- body parts/limbs

(PowerPoint didn’t like video clip…)

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

well… one notable exception

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

GoalAdd “cartoony-ness” into motion-captured data or key-framed data

Goal

Add “cartoony-ness” into motion-captured data or key-framed data

2 Ways to approach this

- using a physical system to model skeleton deformations

+ get different deformations by changing a few intuitive variables (mass, springyness)

- using a filter that only looks at motion curves

+ more aligned with original 2D animation methods (?)

Physical System - Initial Steps-Rotoscoped Mickey’s walk in Maya

-Motion-captured an actor mimicking Mickey’s walk

(videos…)

Bone LengthsHere are the main bones that change lengths to contribute to expression.

Bone LengthsHere are the main bones that change lengths to contribute to expression.

Mass at thorax

Anchor at upperback

Mass at root

Variables

Each spring abides by this equation.

f = m*a = -k*d – b*v

Where

d = length – spring’s rest length

k = spring stiffness coefficient

b = damping coefficient

length

Cartoon Motion and Deformation of Skeletons

Ting Ting WuAdvisor – Nancy Pollard

Background/MotivationWhich looks more interesting?

Which looks more interesting?

Background/Motivation

Most people pick this one

- Anticipation and Follow-through- Stretch and Squash

2 Ways to Apply Stretch and Squash

- posture

- body parts/limbs

(PowerPoint didn’t like video clip…)

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

well… one notable exception

Stretch and Squash in 3D- used extensive for postures

- hardly used at all for limbs

GoalAdd “cartoony-ness” into motion-captured data or key-framed data

Goal

Add “cartoony-ness” into motion-captured data or key-framed data

2 Ways to approach this

- using a physical system to model skeleton deformations

+ get different deformations by changing a few intuitive variables (mass, springyness)

- using a filter that only looks at motion curves

+ more aligned with original 2D animation methods (?)

Physical System - Initial Steps-Rotoscoped Mickey’s walk in Maya

-Motion-captured an actor mimicking Mickey’s walk

(videos…)

Bone LengthsHere are the main bones that change lengths to contribute to expression.

Bone LengthsHere are the main bones that change lengths to contribute to expression.

Mass at thorax

Anchor at upperback

Mass at root

Variables

Each spring abides by this equation.

f = m*a = -k*d – b*v

Where

d = length – spring’s rest length

k = spring stiffness coefficient

b = damping coefficient

length

Variables

Each spring abides by this equation.

f = m*a = -k*d – b*v

Multiple Linear Regression to get k and b!

Should contain the “springyness” of Mickey’s walk.

Ideally, this should allow us to transfer the same kind of stretching and squashing to another moving skeleton.

length

Some of the Data

Plots of d

Some of the Data

Plots of force acting on spring