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Behavior. Autonomous Characters. Self-Directed characters "puppets that pull their own strings" -Ann Marion. Autonomous Characters. Acknowledgement
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Autonomous Characters • Self-Directed characters "puppets that pull their own strings" -Ann Marion
Autonomous Characters • Acknowledgement Much of this material is taken from the work of Craig Reynolds. He maintains a web pages including a rich source of material of steering behavior and the consumate source on flocking. Also see: Steering Behaviors For Autonomous Characters by Craig Reynolds
Three-Tier Hierarchy • Action selection goals and strategies “What to do” • Steering guidance / motion control “How to do it” • Locomotion movement generation “Getting it done”
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.
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.
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.
Seeking and Fleeing • Seeking and Fleeing Applet (Reynolds)
Pursuing and Avoiding • Pursuing and Avoiding Applet (Reynolds)
Flocking Demos • Flocking Applet (Craig Reynolds) • Fish Schooling (Steve Hughes) • Beach House (Ishihama Yoshiaki ) For more demos see Reynolds “Boids in Java”
Do People Flock? Social psychologist’s report the people tend to travel as singles or in groups of size 2 to 5.
Characteristics of Groups • Proximity • Coupled Behavior • Common Purpose • Relationship Between Members
Moving Formations • Pairs: Side by side • Triples: Triangular shape
Stationary Formations Stationary quintuple formed Moving pair approaches stationary triple
Locomotion Model for Walking • Two Parameters • Speed • Combination of step length and step rate • Orientation • Head direction for forward walking
Action Space Accelerate Accelerate Accelerate Turn Left No Turn Turn Right Coast Coast Coast Turn Left No Turn Turn Right Decelerate Decelerate Decelerate Turn Left No Turn Turn Right
Distributed Preference Voting • Delegation of voters: Constraint Proxies • Proxies vote on each cell of the action space • Votes are tallied • Winning cell represents best compromise among competing interests
Vote Tabulation Pursuit Point Tracking Maintain Target Velocity Inertia 1.0 Avoid Peds Maintain Formation Avoid Obstacles 1.0 1.0 Centering 4.0 2.0 5.0 2.0 Electioneer Winning Cell
A Group of Two Following a Path Pursuit Point Tracking Maintain Formation walkway axis -1.0 -1.0 +1.0 -1.0 -1.0 +1.0 -1.0 -1.0 +1.0 +1.0 +1.0 +1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 pursuit point 1.0 2.0 +1.0 +1.0 +3.0 -3.0 -3.0 -1.0 -3.0 -3.0 -3.0 Election for ped 1 ped 2 ped 1 Winning vote = Accelerate/Turn Right
Avoiding an Obstacle -- Trajectory walkway axis walkway axis ped 1 ped 1 ped 2 ped 2 Small look-ahead distance Large look-ahead distance