n Featurelength films n Games n Desktop Animations

n Feature-length films: n Games: n Desktop Animations:

Computer Animation motion control n Keyframing: “hand-crafted” animation n Digitized motion: Motion Capture (mocap) Procedural animation: algorithms to control movement n

Computer Animation Production

Keyframing Digital equivalent to traditional, hand-drawn animation n Animator designs ‘keys’ n Selects interpolation technique and sets timing n System does what traditionally was done by low-paid trainees - automatically computes inbetween frames n

Keyframes

Keyframe…anything n n n Transformations: scale, rotate, translate Shape: squash and stretch Color: e. g. of a flame Image (morphing) Any attribute or parameter

Principles of Animation n n n Arcs Slow-in and slow-out Straight ahead Anticipation Exaggeration Staging Squash and stretch Timing Secondary Action Follow through and overlapping action Appeal Solid drawing Physics Technical approach Aesthetics Efective presentation

Interpolation Linear (yawn) or cubic (e. g. Hermite, Bezier, etc. ) n Interpolation of orientation (rotation) takes special care: quaternions n Need to estimate arc-length n Control acceleration/deceleration: ease-in, ease-out n

Interpolation Show 683 lab

Mocap Several technologies: optical, mechanical, magnetic n n Research on ‘markerless’ mocap Hard to ‘retarget’ to new figure or imaginary creature n

Mocap

Procedural Animation n Set initial conditions - run simulation n Control is an issue n Computational cost (e. g. real-time) is an issue

Kinematics of articulated figures n Forward kinematics n Inverse kinematics n n n Pseudo-inverse of the Jacobian Cyclic Coordinate Descent others…

Kinematics of articulated figures

Physically based simulation Kinematics v. Dynamics n Forces & mass -> acceleration -> velocity -> position n Point mass, particle system n Rigid body dynamics: add rotational dynamics: inertia tensor & torques n Flexible body animation: elastic collisions n

Forces n n n n Gravity Spring Viscosity: damping Friction: static & kinetic Wind field Impulse force of contact Fictional forces

Forces -> n Update n Integration n Numerical integration n Runge-Kutta, Implicit Euler, etc.

Spring-damper-mass system Collection of point masses connected by springs and dampers n n Model cloth, flexible body dynamics n Tricky to set constants and connections

Spring-damper-mass system

Spring-damper-mass system

Spring-damper-mass system Show example animation

Particle system n Collection of point masses n No interaction between point masses n Interact with environment

Particle system

Particle system Show example animation

Rigid body dynamics n Inertia tensor n Conservation of momentum n Coefficient of restitution n Impulse force of collision

Rigid body dynamics Show example animation

Forward dynamics of articulated linkage n Featherstone equations n Traverse linkage forming inertia tensor

Human figure animation n Kinematics of walking, reaching, sitting, standing n Motion capture n Modeling muscles - appearance, dynamics n Dynamics of grasping, handling, lifting

Human figure animation Show animations

Facial animation n Expressions n Lip-sync animation n Emotion

Facial animation Show animations

Behavioral animation n n Flocking Prey-preditor model Crowds Emotion Personality

Behavioral animation Show animations