Computer Animation Algorithms and Techniques

1. Computer AnimationAlgorithms and Techniques Behavioral Animation Rick Parent Computer Animation

2. http://www.gamasutra.com/view/feature/3405/ai_for_games_and_animation_a_.phphttp://www.gamasutra.com/view/feature/3405/ai_for_games_and_animation_a_.php Rick Parent Computer Animation

3. Behavioral Animation Individuals Reactive behavior Intelligent behavior Personality Groups Aggregate behavior Crowd behavior Rick Parent Computer Animation

4. Reactive Behavior If <condition> then <action> current conditions - usually omniscence simple action - carried out directly and immediately problems of scale: conflicting rules priority selection or ordering Rick Parent Computer Animation

5. Aggregate Behavior Typical qualities Rick Parent Computer Animation

6. 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 Rick Parent Computer Animation

7. Primitive Behavior - Flocking Original work by Craig Reynolds 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 Rick Parent Computer Animation

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

9. Navigating Obstacles: Using repulsive forces Rick Parent Computer Animation

10. Navigating using bounding sphere Rick Parent Computer Animation

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

12. Finding closest non-colliding point Rick Parent Computer Animation

13. Navigating – finding a pass Render in z-buffer Sample environments with rays Rick Parent Computer Animation

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

15. Modeling Flight Rick Parent Computer Animation

16. Modeling Flight Rick Parent Computer Animation

17. Modeling Flight Rick Parent Computer Animation

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

19. Intelligent behavior Reasoning Causation Knowledge about environment Vision - immediately sensed Memory - previous experience Rick Parent Computer Animation

20. Vision Omniscience – access to the database FOV vision – culling but no occlusions Occluded vision ray casting – sample environment z-buffer using object IDs as z’s Object recognition - ? Rick Parent Computer Animation

21. Memory What is recorded about the environment Spatial occupancy Transient events: time-stamps Rick Parent Computer Animation

22. Intelligent Behavior Autonomous behavior ‘Self-animated’ characters Perception & reasoning about environment Personality, emotions, dispositions Manifestations of Individuality Body Expressions and Gestures Facial expressions Speech Rick Parent Computer Animation

23. Internal State Models what the agent needs to do Suggested precedence classes of internal state variables Imperatives Desires Suggestions Rick Parent Computer Animation

24. Arbitration among competing intentions Levels of Behavior Hooks for the animator to impose control Rick Parent Computer Animation

25. Expressions and Gestures ToBI – Tones and Break Indices LMA – Laban Movement Analysis BEAT EMOTE RUTH Greta Rick Parent Computer Animation

26. Modeling Individuality Personality – long term qualities Emotions – short term Mood – third level? Basic emotions?: happy, sad, fear, disgust, surprise, anger Models of personality from psychology OCEAN: openness, conscientiousness, extroversion, agreeableness, neuroticism PEN: extraversion, neuroticism, psychoticism OCC: how perceptions dictate emotional experience Rick Parent Computer Animation

27. Modeling Individuality Improv AlphaWolf Rick Parent Computer Animation

28. Crowd Management Emergent behavior Statistical behavior v. believable individual behaviors Homogeneous activity v. Internal structure For evaluation Pedestrian traffic simulation Traffic flow Emergency response modeling For entertainment Background crowds Rick Parent Computer Animation

29. Emergent behavior: similar to flocking collision avoidance ‘intelligent’ paths Crowds From a distance: statistical behavior nonsensical detailed motion reasonable visual effect Internal structure limited interaction among members group formation Rick Parent Computer Animation