Key Frame Animation Amy Gooch AA3: Intro to Animation

3D Animation Rendering 3D Scene and Motion Sequence of Frames –Rates: Video 30fps, Film 24fps Persistence of Vision Animator must create.. Illusion of Life Weight

Animation Almost every property of every object in the scene can be animated (changed through time) –Models, cameras, … –Transformations: Move Rotate Scale –Modifications/Deformation: edits, bends, twists, manipulating a skeleton –materials, colors, textures

Animation 3D Scene does not have –Gravity –Weight –Force –interactions between objects –(bit of a lie) You must make it seem so!

Primary methods of Animation Keyframe Procedural –Expressions –Scripting Dynamics/Simulation –Physics Motion Capture Combinations of the above

Keyframe Workflow 1.Set Keys –Usually extreme positions –Less is more: Keys only the properties being animated 2.Set Interpolation –Specify how to get from one key to another. –Secondary, but a necessary step. 3.Scrub Time slider and refine motion curve

Setting Keys Start with extreme positions Add intermediate positions –Secondary motion Less is more –Don’t add keys for properties that you are not animating –Easier to manage/edit fewer keys

Motion Curves: Position vs. Time

Motion Curves When is the box going Forward? Backward? Fastest? Is the box Starting from stop or at rest? Stopping at the end or continuing?

Interpolation Specify how to get from one key to the other (inbetweening) Common types –Step: stay at the same value, then suddenly switch –Linear: change at constant rate –Spline/Smooth: make it smooth All of these (and more) are useful and appropriate in the right circumstance

Smooth Interpolation Soft changes of direction

Linear Interpolation Hard changes of direction Appears to be contacting other objects, instant changes

Step Interpolation Object reappears in a totally different position This is very useful. When?

Ease In/Out Heavy objects take a while to get going trains Use interpolation to emphasize this. Ease in/out –or- Slow in/out means to leave the key slowly

Timing of the action Ahead of the story –Something will happened before we know what it is audience not yet aware character may knows what’s up –Ex Alien Song Behind the story –Audience knows before character knows –Ex: KnickKnack (1989) Keep audience Interested!

In class: bouncing balls Grab file: Each person will spend 10 minutes making one type of ball bounce Then in turn, each group member will tweak the animation

Resources Laws of Cartoon Physics – htmlhttp:// html Learning Maya Tutorial list – –Skeleton Tutorial –Rag Doll; Skeleton by Proxy tutorial –5-minute Leg Rig

Credits Winny Jessica Hodgins g/Animation/animation.htmlhttp:// g/Animation/animation.html