Autonomous characters

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Autonomous characters

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Computer Animated Characters
A Bugs Life (Pixar/Disney)
Toy Story (Pixar/Disney)
Antz (Dreamworks)
Tomb Raider 3 (Eidos Interactive)
Final Fantasy VIII (SquareOne)
The Legend of Zelda (Nintendo)
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Autonomous Agents

• Definition
• An autonomous agent is a system situated within
  and a part of an environment that senses that
  environment and acts on it, over time, in pursuit
  of its own agenda and so as to effect what it
  senses in the future.

Franklin Graesser, 1996 Is it an Agent, or
just a Program? Proc. of 3rd Int. Workshop on
Agent Theories
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Animated Graphic Agent

• Basic definition Animated character whose
  motion does not need to be explicitly defined by
  a user.

?
Ultimate Goal Fully-autonomous animated agents
able to sense, act, and interact in changing
virtual environments
Other commonly-used terms Digital Actor,
Virtual Human
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Goals vs. Motions
Autonomous Goal Generation Algorithm to decide
what the character should do next (specifies
high-level goal)
Autonomous Motion Generation Algorithm to
generate underlying motion given a high-level goal
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Example Moving an Object
Transfer
Reach
Return
Grab
Release
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Two Classes of Motion

• Primary (Active) Motion gross body movements,
  facial animation
• Secondary (Passive) Motion clothes, skin, hair,
  env. effects

Endgame (Stanford)
Facial animation (Geris Game / Pixar)
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Autonomy vs. Interactivity
Completely Autonomous
Urban / Factory Simulation
Video Game Adversaries
Historical Narratives
Virtual Tour Guides
Digital Actors
Autonomy
Semi-Autonomous Characters
Key-frame Animation Systems
Web Avatars
User-controlled
Off-line
Real-time
Interactivity
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Playing Chess
1997 Geris Game (Pixar)
1994 ENDGAME (Stanford)
1999 Interactive Chess (Stanford)
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Motion Generation Techniques
Scripting Kahn 79, Ridsdale 87, Haumann
Parent 88, Wilhelms 90, Strassmann 91,
Bates, et al. 92, Perlin Goldberg 96
Reactive Behaviors Brooks 85, Reynolds 87, Tu
Terzopoulos 94, Reich, et al. 94, Blumberg
Galyean 95
Kinematic Warping Bruderlin Calvert 89,
Witkin Popovich 95, Unuma, et al. 95,
Gliecher 98
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Motion Generation Techniques
Physically-Based Simulation Armstrong Green
85, Hahn 88, Baraff 89, McKenna Zeltzer
90, Raibert Hodgins 91, Mirtich 95, Ngo
Marks 93, Sims 94, Metaxas, et al. 97
Spacetime Constraints Isaacs Cohen 87, Witkin
Kass 88, Rose, et al. 96, Gleicher 98,
Popovic Witkin 99
Motion Planning Lengyel, et at. 90, Ching
Badler 92, Koga, et al. 94, Bandi Thalmann
97, Hsu Cohen 98
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Motion Planning for Digital Actors
Manipulation
Sensory-based locomotion
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Applications

• Videogames
• Movies
• Ergonomics
• Training
• Web page animation
• Slide shows
• E-commerce

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Types of control system

• Movement Scripts
• Finite State Machines
• Hierarchical State Machines
• Fuzzy State Machines
• Behavioral Anmation
• Pathfinding Techniques
• Planners
• Neural Networks

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Movement Scripts

• ? ???? ????? ?? ??
• ??? ?? ??? ????? ?? ??
• ????? ??

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FSM

• ??? ??? ???? ??? ??? ??? ??
• ?? ??? ?? (?) ?? ?? ??, ?? ?? ??, ?? ?? ??, ??
  ??? ?? ??
• ??? ??? ?? ?? ???? ?? ????? ?? ?? ???
  ??(transition)?? ??? ??
• ?? ??? ?? ??? ?? ??? ???? ??? (?? ???) ?? ?? ??

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FSM
(?) RPG ??? ?? ???? ??
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HFSM
??? ??? ?? ??? ?? ??? ??
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Fuzzy FSM
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???? FuSM? ???? ??

• FuSM? ?? ??? ???? ?? ??
• ?? ??? ?? ?? ??? ??? ??? ????? ??? ?? ???? ??? ?
  ? ??? ?? ? ?? gt ?? ??? ?? ??
• ? ? ???? NPC? ?? ????
• NPC? ?? ?? ????? ?
• ??? ?? ? ???? ?? ? ??
• ?? ?
• NPC? ????? ??? ?? HP
• ??? ???? Ai? ???? ???? ?? ?? ?? ?? ??
• (??, ??, ??, ?? ?? ??)

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Behavioral Animation

• ??? (flocking ?? swarming, herding)
• 1987? SIGGRAPH? ??? Craig Reynolds? Flocks,
  Herds, and Schools A Distributed Behavioral
  Model??? ???? ?? ??? ??
• ???? ????(boid?? ?)?? ??? ??? ????, ?? ??? ??? ??
  ??? ???? ??? ?? ?? ?? gt ?? ?? (steering
  behavior)
• TU realistic fish
• ?? ?? ?? Batman Returns, The Lion King .

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Pathfinding Techniques

• ???
• ??? ?? ??? ? ???? ?? ??? ???? ?? ??? ??? ??.
• ???? ??? ??? ??? ??? ??? ??.
• ?? ??? ?? ?? ??? ???? ?? ???? ??? ??? ??.
• A
• ??? ???? ??? ???? ?? ????? ??? ??? ?? ? ??? ???
  ?? ???? ( ?? ???? ?? ??? ? ?? ??? ??? ???? ???
  ?? )
• ?? ??? ?? ? ??? ??? ??? ???? ??? ??? ?? ? ??
• ?? ??? ??? ??? ? TotalCost(X)? ?? ?? ??? ??? ?
  ??? ?? ( TotalCost(X) CostFromStart(X)
  CostToGoal(X) )

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Planners

• Classic Planners STRIPS
• (?) SOAR planner quake
• Planners
• Sense
• Plan
• Act

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(No Transcript)
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(No Transcript)
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Neural Networks

• Perceptrons
• Multilayered Forward Feed Networks
• Back Propagation

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People and previous work on the subject

• Craig Reynold and the Behavioral Animation
• Blumbergs research group
• Tu
• Demetri Terzopoulos
• Perlin
• Steve Grand
• John Laird
• Lars Liden

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Craig Reynold and the Behavioral Animation
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?? ??(steering behavior)

• ?? (Separation)
• ?? ????? ???? ??? ??? ???
• ?? (Alignment)
• ?? ????? ?? ??? ????? ??
• ?? (Cohesion)
• ?? ?????? ?? ????? ??? ???
• ?? (Avoidance)
• ??????? ??? ???? ??? ??? ????

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?? (Separation)

• ???? ??? ?? ???? ??? ??? ????? ?? ?
• ????? ??? ????? ?? ???? ???, ??? ???? ?? ?? ??
• ??? ? ????? ?? ????? ??? ???? ??? ??? ??? ? ???
  ??? ??? ???? ? ??? ???

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?? (Alignment)

• ???? ??? ?? ???? ??? ??(?? ??)? ????? ?? ?
• ? ??? ?? ????? ?? ??? ?? ??? ????? ???? ?
• ? ????
• ???? ??? ??? ?? ????? ???? ??? ???? ?????? ? ???
  ???

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?? (Cohesion)

• ????? ??? ???? ??? ?? ??
• ?? ?????? ?? ??? ? ? ??? ???? ??? ??? ?????? ? ??
  ??

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?? (Avoidance)

• ???? ???? ???? ??? ?? ?? ?
• ???? ?? ??? ??? ?? ?? ???? ???? ??? ?? ? ?? ???
  ??? ?????? ??
• ? ??? ????? ??? ??? ??? ???? ????(??? ?? ??, ???
  ?? ?)? ?? ??? ??

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?? ?? ????

• ??? ???? ??? ?? ??? ??(??? ??? ?? ? ?)? ??? ????
  ?
• ???? ??? ?? ??? ??? ???? ??? ????
  ????(stateless) ????
• ??? ???? ? ???? ??? ??? ?? ??? ?, ??? ?? ??? ??
  ??? ?? ??
• ??? ??? ?? ??? ??? ?? ?? ????? ?? ??? ???? ??? ??
• ?? ???? ?? (emergent behavior)
• ??? ????? ??? ??? ?? ?? ???? ?? ?? ????, ?? ?????
  ??? ???? ????, ???? ??? ???, ?? ????? ??? ???
  ????? ???? ?

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????? ??

• ???
• ???? ?? ??? ?? ??
• ????? ? ? ??? ?? ?? ??? ???? ??
• ?? ?? ???? ?? ??
• Unreal(Epic)? Half-Life(Sierra)? ?????? ?? ? ?
  ??? ???(???? ?)? ???? ???? ???
• Enemy Nations(Windward Studio)? 3D ?? ???? ?? ??
  ??? ??? ??? ??? ???? ??
• RTS ???? RPG?? ???? ??? ??? ? ??? ??????? ????
  ???? ?? ?? ? ??? ?? ??? ?? ? ??
• 1?? ?? ????, ?? ?? ????? ?? ??? ?? ??? ????? ????
  ??? ??? ????? ???? ??? ??? ??

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Flocks in Film

• 1987 Stanley and Stella in Breaking the Ice,
  (short)
• Director Larry Malone, Producer
  Symbolics, Inc.
• 1988 Behave, (short)
• Produced and directed by Rebecca Allen
• 1989 The Little Death, (short)
• Director Matt Elson, Producer Symbolics,
  Inc.
• 1992 Batman Returns, (feature)
• Director Tim Burton, Producer Warner
  Brothers
• 1993 Cliffhanger, (feature)
• Director Renny Harlin, Producer Carolco.
• 1994 The Lion King, (feature)
• Director Allers / Minkoff, Producer
  Disney.

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Flocks in Film

• 1996 From Dusk Till Dawn, (feature)
• Director Robert Rodriguez, Producer
  Miramax
• 1996 The Hunchback of Notre Dame, (feature)
• Director Trousdale / Wise, Producer
  Disney.
• 1997 Hercules, (feature)
• Director Clements / Musker, Producer
  Disney.
• 1997 Spawn, (feature)
• Director Dipp?, Producer Disney.
• 1997 Starship Troopers, (feature)
• Director Verhoeven, Producer Tristar
  Pictures.
• 1998 Mulan, (feature)
• Director Bancroft/Cook, Producer Disney.

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Flocks in Film

• 1998 Antz, (feature)
• Director Darnell/Guterman/Johnson,
  Producer DreamWorks/PDI.
• 1998 A Bugs Life, (feature)
• Director Lasseter/Stanton, Producer
  Disney/Pixar.
• 1998 The Prince of Egypt, (feature)
• Director Chapman/Hickner/Wells, Producer
  DreamWorks.
• 1999 Star Wars Episode I--The Phantom Menace,
  (feature)
• Director Lucas, Producer Lucasfilm.
• 2000 Lord of the Rings the Fellowship of the
  Ring (feature)
• Director Jackson, Producer New Line Cinema.

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Blumbergs research group
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- ????? ??? ??
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Tu Demetri Terzopoulos

• Physical Fish Model
• Animate vision - a paradigm which prescribes the
  use of artificial animals as autonomous virtual
  robots for active vision research

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Qualities of Fish Animat

• Motor system
• Perception system
• Behavior system
• Form and Appearance

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Motor System

• Comprises the fish biomechanical model, including
  muscle actuators and a set of motor controllers
  (MCs)

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Perception System

• Model limitations as well as abilities
• Perceptual attention mechanism - allows animat to
  act in a task-specific way

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Behavior System

• Mediates between the perception system and the
  motor system of the fish

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Form and Appearance
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Eyes and Retinal Imaging
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Navigation

• Once targets are located and can be tracked,
  navigation is trivial.
• When left-right vision angles deviate by more
  than 30 degrees from center, tell body to turn
  left/right.
• When up-down vision angles deviate by more than 5
  degrees, tell body to push up/down.

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Picture from Pursuit
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Conclusions, Looking Forward...

• Achieved goal of implementing a software-based
  artificial life simulation.
• In the future, would like to develop a better
  active vision algorithm more suited to real fish.
• Model can be made realistic enough to use
  resulting data to form theories about animals and
  robotic situated agents.

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Et al.

• Perlin generating noise in 3D space for
  realistic artificial textures
• Steve Grand neural network
• John Laird SOAR Architecture (advanced
  autonomous AI systems for large scale real time
  simulations)
• Lars Liden
• Monsters behavior based on players actions
• Group behavior and cooperation among monsters
• Multisensory monsters