Administrations

Course website: http://www-scf.usc.edu/~csci520

Computer animation My office hours: Tue 1:00-3:00 PM, SAL 216

TA: Sumit Jain

TA’s office hours: Wed 2:00-4:00 PM

Prerequisites Grading schemes

CS 480 or CS 580

Thorough understanding of linear algebra Project (90%)

Vector calculus Paper presentation (5%)

A good working knowledge of C and C++ Participation in the class (5%) programming Projects Paper presentation

Find a parter (different from your project partner) Project 1: Animation system (15%) Choose a paper from the list Project 2: Constrained particle systems (25%) Sign up with the TA Project 3: Inverse kinematics (25%) You have 10 weeks to learn the materials Project 4: Final project (35%) Come to my office hours if you need help

Who am I? What do I expect?

Graduated from the University of Washington, Dept Teach you every thing I know about Animation of Computer Science and Engineering (2005) Teach you how to find and formulate your research Thesis topic: Towards a Generative Model of problems Human Natural Motion Inspire some of you to do research with me What should you expect? Animation in the silent era (1900-1930)

A class that takes a lot of your time (I’m not kidding)

A class that forces you to work with real people “Gertie the Dinosaur (1914)”

You need to brush off your linear algebra and calculus

Being a good programmer is not crucial, but it

certainly helps “Farmer Alfalfa & His “Felix the Cat (1923)” Terrytoon Pals (1916)”

Golden age of animation Animation in television era (1930-1950) (1950-1980)

“Betty Boop (1930)” “Snow White (1937)” “Bugs Bunny (1940)”

“Heckle and Jeckle “Mighty Mouse “The Flintstones (1946-1966)” (1950-1980)” (1960-1966)”

“Fantasia (1940)” “Tom and Jerry” (1940) “Bambi” (1942) Modern animation (1980-present) Principles of animation

12 animation principles for creating character animation were developed at the Disney Studio in the 1930s

“The Little Mermaid (1992)” “Jurassic Park (1993)” “Toy Story (1995)” John Lasseter (Pixar) introduced them to the computer animation community in 1987 in a SIGGRAPH course

Question: how to support these principles in computer tools?

“Final Fantasy (2001)” “Half Life 2 (2004)”

1. Squash and stretch 2. Anticipation

Anticipation allows an animator to accentuate a Character composed of living character’s action as it flesh that deforms to accurate directs the viewers attention movement

Can be as simple as facial Exaggerate deformations expression or as broad as the emphasize motion and impact body windup

Volume conservation is the Don’t surprise your key audience unless it is intentional 2. Anticipation 3. Staging

Staging is the consideration of camera, framing and the position of characters

Staging can help to exaggerate action and impact

The audience’s eye must be led to exactly where it needs to be at the right moment

3. Staging 4. Straight ahead and pose to pose

Two methods of drawing a scene

Straight ahead action starts with an idea in mind and draw all frames until done

Used for wild, scrambling action where spontaneity is important

Pose to pose draws the keyframes first and then fill in the in-betweens

“Monsters Inc. (2001)” Used for animation requiring precise acting and timing 4. Straight ahead and pose to pose 5. Follow through and overlap

Nothing stops abruptly in reality

Follow-through is also evident in secondary motion

Slight variations in timing “The Incredibles (2004)” “Wallace and Gromit (2005)” and speed of loose parts make the object seem more Which one is made by straight ahead action? natural

6. Slow in and slow out 7. Arcs

To stress the keyframes, move slowly away from one keyframe, quickly in Nothing living ever the in between frames, really move in a and slowly into the next perfectly straight line keyframe Most human motion Used for exaggerating the happens on curved acceleration and trajectories deacceleration occurring at the extremes 7. Arcs 8. Secondary actions

Action aside from the of the primary character

Must not distract the audience

Often reveal subtle emotions or hidden thoughts

9. Timing 10. Exaggeration

Walt Disney wanted exaggeration with believability Timing plays an essential role in illustrating the Used to increase the readability emotional state of a of emotions and actions character

Exaggerated poses often look Timing can also define the ridiculous when viewed as weight and the inertia of stills, but they add essential the characters impact when viewed in a split second 11. Solid drawing 12. Appeal

Drawing motion is a critical Appeal is what activity for animators makes people want to look at a character Observation improves the fundamental skills of Even a villain can composing a scene, character have appeal proportions, and timing

A design that is Also allows the rapid complicated or hard development of ideas before to read lacks appeal committing a design to screen

Luxo Jr. Beyond entertainment

Biomechanics

Robotics

Scientific visualization

Education

How many animation principles does Luxo Jr. follow? Anthropology Animation research Traditional animation

That was then... Film runs at 24 frames per sec; Techniques Objects Tools that is, 1440 pictures to draw in one minute Rigid body Traditional Synthesis Artistic vision has to be Deformable body Physics-based Editing converted into a sequence of Articulated body Data-driven Compositing still “keyframes” Performance- Face Simulation based Hair and cloth Hard to draw consistent “in- Natural phenomena between” frames Not enough to get the still right; must to look right at full speed

Computer assisted animation Traditional animation

This is now That was then... This is now Generate the images by rending a 3D model Manually set the parameters for each keyframe Automatically interpolate between two drawings to produce inbetweens Do computers really expedite the process of creating animation? Physics-based methods Physics-based methods

Generate motion by applying physical laws Rigid body simulation

Simulate physical phenomena associated with motion gravity momentum (inertia) collisions friction deformation Fast frictional dynamics for rigid bodies Kaufman et. al. Siggraph 2005 fracture

Physics-based methods Physics-based methods

Rigid body simulation Rigid body simulation

Deformable object simulation Deformable object simulation

Character animation

BD-Tree: Output-sensitive collision detection Learning physics-based motion style for reduced deformable models with nonlinear inverse optimization James et. al. Siggraph 2004 Liu et. al. Siggraph 2005 Physics-based methods Data-driven methods

Rigid body simulation Human motion

Deformable object simulation

Character animation

Natural phenomena simulation Water drops on surfaces Motion synthesis from annotations Wang et. al. Siggraph 2005 Arikan et. al. Siggraph 2003

Data-driven methods Data-driven methods

Human motion Human motion

Facial animation Facial animation

Human body deformation

Automatic determination of facial muscle activations from sparse SCAPE: Shape completion and motion capture marker data animation of people Sofakis et. al. Siggraph 2005 Anguelov et. al. Siggraph 2005 Performance-based animation The making of LOTR

Record the animation from live action

rotoscope: trace over video of real motions

motion capture: track motion of reference points in 3D

Useful math Useful background knowledge

Differential equations Physics

Optimization methods Mechanics

Statistical models Biomechanics What’s next?

Keyframe animation

Interpolation using cubic splines

Speed control