1. Computer Animation Rick Parent Computer Animation Algorithms and Techniques Behavioral Animation: Knowing the environment Flocking

2. Computer Animation Rick Parent Behavioral Animation Knowing the environment Aggregate behavior Primitive behavior Intelligent behavior Crowd management

3. Computer Animation Rick Parent

4. Computer Animation Rick Parent Knowing the environment Vision – what do you know about the present Memory – what is recorded about the environment More about AI than graphics

5. Computer Animation Rick Parent Vision Geometric issue – what’s in sight? OR Can I see X? Perceptual issue – what do you see? Computation v. accuracy Cognitive modeling – necessary? At what level?

6. Computer Animation Rick Parent Omniscience Everything in database is ‘known’

7. Computer Animation Rick Parent FOV Vision Use surrogate bounding volumes, or sample points

8. Computer Animation Rick Parent Occluded Vision ray casting sample environment z-buffer use object IDs as color Use surrogate bounding volumes

9. Computer Animation Rick Parent Target-testing vision Can I see X? Cast ray Use surrogate bounding volumes Sample object

10. Computer Animation Rick Parent Object Recognition Cognitive modeling How much and what part is needed? Application need? Not yet addressed in literature More AI than graphics

11. Computer Animation Rick Parent Other senses? Hearing? Smell? Model sensors & signal propagation Spatial occupancy approach? Applications?

12. Computer Animation Rick Parent Memory What is recorded about the environment Transience of objects: time-stamps Spatial occupancy hierarchy: short-term, long-term

13. Computer Animation Rick Parent Spatial Occupancy doorway transiency wall

14. Computer Animation Rick Parent Aggregate Behavior: E pluribus unum Emergent Behavior TypeElementsPhysics Env/Others Intelligence Particles10 2 -10 4 Much/noneNone Flocking10 1 -10 3 Some/someLimited Crowds10 1 -10 2 Little/muchLittle-much Typical qualities

15. Computer Animation Rick Parent Primitive Behavior - Flocking Local control – for realism, the flock member only reacts to locally accessible information Perception – FOV vision – angle can change with speed Interacting with other members – stay with friends, avoid bumping into each other Interacting with the environment – collision avoidance is primary

16. Computer Animation Rick Parent Primitive Behavior - Flocking Global control – need control of flock script flock leader global migratory urge Negotiating the motion Collision avoidance – steer to avoid Splitting and rejoining – difficult to tune parameters Modeling flight – e.g., banking into turns Original work by Craig Reynolds

17. Computer Animation Rick Parent Negotiating the Motion Forces Or “Reasoning” (e.g. rule-based)

18. Computer Animation Rick Parent Navigating Obstacles Problems with repulsive forces

19. Computer Animation Rick Parent Navigating using bounding sphere

20. Computer Animation Rick Parent Navigating Testing for being on a collision path with (bounding) sphere Given: P, V, C, r

21. Computer Animation Rick Parent Finding closest non-colliding point Calculate s,t

22. Computer Animation Rick Parent Navigating – finding a pass Vision Options: Render in z-buffer Sample environments with rays

23. Computer Animation Rick Parent Modeling Flight –common in flocking

24. Computer Animation Rick Parent Modeling Flight

25. Computer Animation Rick Parent Modeling Flight

26. Computer Animation Rick Parent Modeling Flight

27. Computer Animation Rick Parent Primitive Behavior - Prey-Predator unbalanced abilities vision - distance, movement, fov maximum velocity maximum acceleration maximum angular velocity maximum angular acceleration

28. Computer Animation Rick Parent Prey-Predator - vision

29. Computer Animation Rick Parent Prey-Predator agility: speed and turning

30. Computer Animation Rick Parent Prey-Predator – hidden by forces Using pure forces May not prevent object penetration Prey can be ‘hidden’ by environmental repulsive forces