1. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics1 Introduction to Advanced Animation Types of animation Low Level Control (a start) (Ch. 15) We’re going to be examining topics from chapters 15, 16, 17, 18 in the textbook. 15 – Low level control 16 – Articulated structures 17 – Soft object animation 18 – Procedural animation

2. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics2 Plan Introduction (Ch. 15) Skeletal animation (Ch. 17) Curves and cubic interpolation (Ch. 15) Kinematics and inverse kinematics (Ch. 16) Procedural animation (Ch. 18) Water and physical models

3. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics3 Types of Animation Procedural animation – Animation is defined by a computational result Representational animation – Animation is defined by example Stochastic animation – Animation is based on random phenomena Behavioral animation – Animation is a reaction

4. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics4 Low level control How do we specify animations? Assuming a simple skeleton with 12 3DOF joints – 36 numbers per frame – 64,800 numbers per minute – We just can’t do this manually – Would we ever have this?

5. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics5 Scripting systems We have some programming language that defines the motion – Procedural animation (defop spin-cube-actor (param: color) (actor (local: (angle 0) (d-angle (quo 3 runtime)) (my-cube (recolor color cube))) (see (rotate angle y-axis my-cube)) (define angle (plus angle d-angle)))) Actor Script Animation System (ASAS)

6. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics6 Keyframing and “Tweening” Define motion at specific points Interpolate between the points – Tweening – generating intermediate frames – Inbetweens – The generated intermediates How to interpolate this example?

7. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics7 Types of interpolation Linear – x(t) = (1-  t/t) x 1 +  t/t x 2 Cubic – x(t) = as 3 + bs 2 + cs + d – Where do we get a, b, c, d? Points, angles, orientations? When does this not look good?

8. CSE 872 Dr. Charles B. Owen Advanced Computer Graphics8 Spline-driven animation We define a animation using control points that “attract” the animation Control points may be on (interpolated control points) or near the curve We’re going to cover curves shortly.