ARTIS-GRAVIR / IMAG INRIA ICA INPG A Physically-Based Particle Model of Emergent Crowd Behaviors...
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Transcript of ARTIS-GRAVIR / IMAG INRIA ICA INPG A Physically-Based Particle Model of Emergent Crowd Behaviors...
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
A Physically-Based Particle Model of Emergent Crowd
Behaviors
Laure Heïgeas, Annie Luciani,
Joelle Thollot, Nicolas Castagné
ICA INPG
ARTIS-GRAVIR/IMAG INRIA
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
The agora of Argos•Center of the social life
•A visitor should have a feeling of this
•We need to put people walking around during our walkthrough session
•CG research question : how to animate a crowd and to render it in real time ?
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
What kind of crowd
•We focus on collective behavior
•One character has to avoid others and buildings
•We try to produce some emergent behaviors: flows, files, groups
•We need a generative model
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
State of the art•Three main approaches:
– Kinematic: key frames and interpolations preset the animation
– Agent systems: agents are managed in real time by rules of behavior defined with automata
– Particle-based system: particles are animated in real time by the application of different forces
•Particle systems seem to be well adapted: generative and simple, no need for special rules
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
Our methodology•Analysis of the dynamic of a crowd:
– Dynamic structures• Traffic jams
• Flows
• Queues
– Obstacle avoidance• Distance around obstacles: apparent volume
• Distance around people: psychophysical volume
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
Our methodology• Synthesis of the dynamic effects
– One character = one particle on a 2D ground
– Building = several particules
– Elastic interaction, piecewise linear• Thresholds given by the analysis
C - Impenetrable zone
B - Avoidance zone
A - Long DistanceAnticipation zone
F
D
D1 D2 D3
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
Results•2D visualization of the trajectories
Avoidance of two persons passing face to face
The red discs form a queue and the green ones jam together
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
3D visualization•NPR style
– Coherent with the style of the scene– Historical references for the costumes
•Real-time rendering– Each character is a billboard– We texture it with a movie of a walking person:
20 points of view and 8 different characters
[ Loscos et al. 02]
ARTIS-GRAVIR / IMAG INRIA
ICA INPG
Conclusion•Results:
– Reproduction of complex dynamic behaviors– Simple interaction model between pairs of objects– 3D real-time visualization
•Future works– Allowing the user to interact with the crowd real-time simulation– Anisotropic model of a character: front/back