Ch11 0 Behavior

Computer AnimationAlgorithms and Techniques: 

Computer Animation Algorithms and Techniques Behavioral Animation

Slide2: 

Behavioral Animation Knowing the environment Aggregate behavior Primitive behavior Intelligent behavior Crowd management

Slide3: 

Knowing the environment Vision – what do you know about the present Memory – what is recorded about the environment More about AI than graphics

Slide4: 

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 - ?

Slide5: 

Memory What is recorded about the environment Transient events: time-stamps Spatial occupancy

Slide6: 

Aggregate Behavior Typical qualities

Slide7: 

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

Slide8: 

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

Slide9: 

Negotiating the Motion

Slide10: 

Navigating Obstacles: Using repulsive forces

Slide11: 

Navigating using bounding sphere

Slide12: 

Navigating Testing for being on a collision path with (bounding) sphere Given: P, V, C, r

Slide13: 

Finding closest non-colliding point

Slide14: 

Navigating – finding a pass Render in z-buffer Sample environments with rays

Slide15: 

Modeling Flight –common in flocking

Slide16: 

Modeling Flight

Slide17: 

Modeling Flight

Slide18: 

Modeling Flight

Slide19: 

Primitive Behavior - Prey-Preditor unbalanced abilities maximum velocity maximum acceleration maximum angular acceleration maximum angular velocity vision - distance, movement, fov

Slide20: 

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

Slide21: 

Internal State Suggested precedence classes of internal state variables Imperatives Desires Suggestions Models what the agent needs to do

Slide22: 

Levels of Behavior Hooks for the animator to impose control

Slide23: 

Expressions and Gestures BEAT EMOTE RUTH Greta ToBI – Tones and Break Indices LMA – Laban Movement Analysis

Slide24: 

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

Slide25: 

Modeling Individuality Improv AlphaWolf

Slide26: 

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

Slide27: 

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