Animation CS 551 / 651

1. AnimationCS 551 / 651 Lecture 3 Classical Animation

2. Review • Keyframing • Provides extensive user control • Automated but difficult to capture artist effects • Liner, nonlinear, easing, squash/stretch, anticipation, follow-through, secondary motion

3. Review • Motion Capture • Easy to capture style, but difficult to reuse/adapt • Data cleanup / foot sliding

4. Review • Procedural • Build once, use often • Difficult to build http://taat.fi/taat/porrasturvat/ www.sodaplay.com

5. Euler Angle Interpolation • Euler Angle (Roll, Pitch, Yaw) • Frequently encoded as 3x3 matrix • Simple interpolation fails: • Identity Rotate 90 degrees Interpolated about x axis (not orthonormal)

6. Principles of Computer Animation • John Lasseter, "Principles of Traditional Animation Applied to 3D Computer Animation", Computer Graphics, pp. 35-44, 21:4, July 1987 (SIGGRAPH 87). • Ollie Johnston and John Lasseter, Course 1 at SIGGRAPH 94, "Animation Tricks".

7. Comments from LasseterKeyframing • Computers are stupid • Worst case, keyframe require for every frame • John discovered that some degrees of freedom (DOFs) require more keyframes than others to look natural • You must start with a clear idea of the motion you desire • Plan actions with thumbnail sketches and plot timing on exposure sheet • Refer to sketches/timing frequently

8. Lasseter: 2-D vs. 3-D • Native computer character is 3-D • Sometimes makes it harder • A character’s hand may go through its body when seen from a certain angle • Sometimes makes it easier • Animation reuse: An animation may look very different when seen from different locations

9. Lasseter: Weight and Size • Rendering can make realistic-looking objects (marble, feathers, steel) • Good rendering benefits are lost if animation is poor • Physics matters – heavy things take longer to start/stop moving… • Proper timing/spacing of poses is more important than the poses themselves

10. Lasseter: Thinking Character • Every motion must exist for a reason • Mood • Personality • Attitude • You must convey the character’s thoughts to tell the story • Use anticipation

11. Lasseter: Anticipation • Lead with the eyes • Move eyes first, with lock-in of focus a few frames before the head • Head follows and leads the body by a few frames • More delay implies more thought required • Use this relationship as a tool • External forces cause opposite timing relationship

12. Lasseter: Moving Holds • Traditional 2-D animation permits “holds” • Reuse of one drawing for multiple frames • This is one way to control timing • In computer animation action dies immediately • Perhaps due to realistic rendering and smooth animations • Eye picks it up every time

13. Lasseter: Moving Holds • Have some part of the character continue to move in same direction during holds • Remember to coordinate realism of character to realism of motions • More realistic characters (rendering style and dimensions) require more realistic movements • This rule limits the straightforward reuse of human facial mocap for non-human 3D characters

14. Lasseter: Emotion • Character’s personality conveyed through emotion • Emotion dictates animation pace • Distinguish emotional state of two characters through contrast in movement • No two characters perform same action in same manner

15. Lasseter: Readability of Actions • To make sure an idea or action is unmistakably clear, the audience’s eye must be led to the right place at the right time • Timing • Not too slow or audience eyes wander • Not too fast or action is misunderstood • The faster the motion, the more critical it is to make the audience focus on it Harold Whitaker and John Halas, Timing for Animation, 1981

16. Readability of Actions • Staging • Audience can only see one idea at a time • Object of interest must be contrasted against rest of scene • Pick strongest and simplest technique ex: Still object vs. busy background

17. Lasseter: Readability of Actions • Anticipation • First action should not be brought to complete stop before starting second • Slight overlapping preserves flow • ex: Luxo Jr.

18. Lasseter: Story Tricks • Animation must be timed to stay slightly ahead or behind audience’s understanding • Ahead conveys suspense and surprise • Initial scene of Luxo Jr. where Dad is surprised by ball • Closing scene of Red’s Dream • Behind reveals the story to the audience before a character to convey character’s discovery

19. Lasseter: Ask Why • Why is this here? • Does it further the story? • Does it support the whole? • Change of shape shows a character is thinking • “It is the thinking that gives the illusion of life.It is the life that gives meaning to the expression”1 • “It’s not the eyes, but the glance – not the lips, but the smile”2 • Frank Thomas and Ollie Johnston, Disney Animation – The Illusion of Life, 1981 • Saint-Exupery, Wind, Sand, and Stars, 1932

20. Johnston Notes • Use attitudes and actions to illustrate ideas and thoughts, not words and mechanical movements • Squash and stretch the entire body for attitudes • Preserve volume • Useful for face too

21. Johnston Notes • Change of expression and dialog are points of interest – don’t move head too much • Concentrate on drawing clear, not clean • Everything has a function – know why • Let the body attitude echo the facial • Find best part of character’s pose to squash and stretch

22. Johnston Notes • The eye is pulled by the eyebrow muscles • Get a plastic quality in the face • Cheeks, mouth, and eyes • The audience has a difficult time reading the first 6 – 8 frames • Actions can be eliminated and staging “cheated” if it simplifies the picture you are trying to show and it doesn’t disturb the audience

23. Johnston Notes • Spend half your time planning your scene and the other half animating • How to animate a four-legged walk: • Work out acting patterns with squash and stretch in body, neck, and head • Animate the legs • Adjust up and down motion of body according to legs

24. Anticipation • Can be anatomical • Swinging your foot back before kicking • Device that attracts viewer’s attention • Staring off camera until character enters at that position • Can help convey mass. More wind-up or concentration implies increased scale

25. Staging • Contrast is powerful staging technique • Motion is one example • Original Disney characters were black and white (no grayscale) • Important motions had to be drawn in silhouette because limbs passing in front of others were not easy to see • Even when grayscale (and color) is possible, silhouette makes actions more visible

26. Follow through and Overlapping Action • "It is not necessary for an animator to take a character to one point, complete that action completely, and then turn to the following action as if he had never given it a thought until after completing the first action. When a character knows what he is going to do he doesn't have to stop before each individual action and think to do it. He has it planned in advance in his mind." Walt Disney

27. Ease-in and Ease-out • A facsimile of physics • First, second, and third order continuity • Remember challenges getting splines to interpolate endpoints

28. Digital Editing • Frames are always represented digitally (no degeneration) • Infinite compositing • 21Mb/sec required for playback • 1 hour of video = 76 Gb of storage • D1 and digital Betacam are industry standard • Digital to analog or film?

29. Homework • Reader Hecker articles 1 and 2