1. Fundamentals of Computer Animation
Wrap-up Overview

2. Animation Timeline in Movies
Conventional Animation (Techniques/Process)
Role of the Computer
3D Animation
Reading:
Jessica K. Hodgins and James F. O'Brien
“Computer Animation”
(check web site)

3. Timeline  The Illusion of Motion
1824, Peter Mark Roget,"Persistence of Vision with Regard to Moving Objects“
a series of images shown in rapid sequence can appear to move fluidly (i.e. a flip book or film projector)

5. Timeline  Movies (1895) age of movie camera and projector begins
experimentors discover they can stop the crank and restart it again to obtain special effects
(1914) Gertie, Windsor McCay (newspaper cartoonist)
first popular animation
(1928) Steamboat Willie, Disney
an early cartoon w/ sound
cartoons seem plausible as entertainment
(1933) King Kong, Willis O’Brien
(1930’s & 40’s) Golden age of cartoons
Betty Boop, Popeye, Porky Pig, Daffy Duck, Bugs Bunny, Woody Woodpecker, Mighty Mouse, Tom & Jerry
(1937) Snow White, Disney
animated feature film
cost is $1.5M

6. Timeline  Movies (cont)
(1982) Tron, MAGI
movie with a computer graphics premise
(1984) Last Starfighter
computer graphics was used interchangably with actual models of the spaceship
(1993) Jurassic Park
computer graphics is used to create living creatures that are meant to appear realistic
(1995) Toy Story, Pixar
full-length feature film done entirely with 3D computer animation
(2000) CyberWorld 3D, IMAX
3D IMAX full-length feature film including characters from popular 3D movies such as ANTZ and The Simpsons’ Homer

7. Conventional Animation Techniques
Drawing on film
Multiple drawings
Rotoscoping (project film of real actors onto drawing paper)
Stop motion animation
Acetate cels, multiple plane cells

8. Conventional Animation Process
Storyboard
Key frames drawn
Straight ahead vs. pose-to-pose
Intermediate frames filled in (inbetweening)
Trial film is made (called a pencil test)
Pencil test frames transferred to cels

9. Conventional Animation Process

10. Role of the Computer In-betweening Disney’s CAPS system
artistic example: Hunger, Peter Foldes 1974
Disney’s CAPS system
scanned artist drawings are read in
"cels" are colored online (broad color palette, exact color matching)
compositing is done online (background, 2D drawings, 3D animation)
3D effects can be created with 2D drawings (e.g. Beauty and the Beast)
used in every film since Beauty & Beast
3D graphical worlds
can experiment more easily with actor position, camera position
can perform more complex camera moves
exchange labor to create drawings with labor to build and animate 3D world

11. 3D Animation 3D animation is similar to stop motion animation
King Kong (1932)
Flash Gordon (1972)

12. 3D Animation Stop motion animation (Nightmare Before Christmas)
3D keyframing (Luxo Jr.)
Performance animation and motion capture (Donkey Kong Country)
Which must be done straight-ahead and which can be animated pose-topose?

13. Keyframing
Key frames mark important visual transitions (extremes of action)
Inbetweening is creation of intermediate frames between the key frames
Can easily be calculated by computer

14. Temporal Sampling
Film recording takes samples of an image at fixed time intervals
24 frames per second for film
30 frames per second for video
human eye "sees" continuous motion
Sometimes, fewer keyframes are required to describe the motion, especially for “pencil tests” or rough choreography (e.g., Lost World)

15. Smooth Motion  (1) Passive Physics
No internal energy source and move only when an external force acts on them.
Read for use when:
physical laws encoded
initial conditions specified
Pools of water, clothing, hair, leaves

16. Smooth Motion  (3) Passive Physics
Clothing (Geri’s Game)
Water (Antz)
“Rigid” body physics (crashing space pods in Phantom Menace)
Geri’s Game, Pixar Animation Studios

17. Smooth Motion  (2) Active Physics
User specifies keyframes (start, end, middle)
User specifies constraints (e.g. laws of physics)
System searches for minimum energy motion to accomplish goals
A. Witkin and M. Kass,
“Spacetime Constraints”,
SIGGRAPH ‘88.

18. Smooth Motion  (3) Active Physics and Simulation
Control an animated character as we would control a robot
behavior is simulated
a "control system" sends proper signals to the character’s "muscles" over time
Mark Raibert’s leg lab at MIT

19. Noise Motion We generally don’t want motion to be too smooth
The eye picks up symmetries and smooth curves and interprets them as artificial or fake
By adding noise, we can add texture to smooth motion
K. Perlin, “An Image Synthesizer”,
Computer Graphics, 19(3), July 1985.
Perlin, Improv system
(K. Perlin and A. Goldberg, SIGGRAPH ‘96).
Applets:

20. Noise Motion
Motion capture (natural noise!)