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Hierarchical Model for Real Time Simulation of Virtual Human Crowds

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Soraia Raupp Musse and Daniel Thalmann. Topics in Computer ... (SB) (RB) (SB) (GB) (RB) Topics in Computer Graphics, Spring 2004. 7. Results & Discussion (2/2) ... – PowerPoint PPT presentation

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Title: Hierarchical Model for Real Time Simulation of Virtual Human Crowds


1
Hierarchical Model for Real Time Simulationof
Virtual Human Crowds
  • Soraia Raupp Musse and Daniel Thalmann

2
Contents
  • Introduction
  • Related work
  • Crowd structure
  • Crowd information
  • ViCrowd architecture
  • Behaviors
  • Results discussion
  • Conclusions

3
1. Introduction (1/3)
  • ViCrowd
  • A behavioral-based multi-level framework to
    simulate virtual human crowds in real time
  • Concepts
  • Virtual human agent
  • Simulation Entity Crowd Groups Agents
  • crowd set of groups, group a group of agents
  • Intentions, beliefs, knowledge
  • Crowd behavior
  • Events

4
1. Introduction (2/3)
  • Problems
  • Modeling of crowd information and hierarchical
    structure, also concerning its distribution among
    groups
  • Different levels of realism variation in
    behavior complexity
  • The required structure to provide interaction
    with groups of agents during the simulation in
    real-time
  • Solutions
  • A hierarchy composed of crowd, groups, and agents
    is used? Crowd structure
  • Endowing virtual agents with different levels of
    autonomy ? Crowd behavior (programmed, reactive,
    autonomous, guided)

5
1. Introduction (3/3)
  • Group based model
  • Automatic generation of human crowds based on
    groups
  • Groups are more intelligent than individuals.
  • Real time Requirements and information
    optimization
  • Based on flocking systems
  • Contributions
  • Multi-level hierarchy
  • Various degrees of autonomy
  • Group-based behaviors

6
2. Related Work (1/2)
  • Modeling the motion of groups with significant
    physics
  • Particle systems Bouvier
  • Crowd simulation with dynamics Brogan
  • Distributed behavior model for simulating flocks
    Reynolds
  • Methods to simulate the movement of pedestrians
    Helbing
  • Local rules for controlling collective behaviors
    Matraric, Noser
  • Behavioral animation for creating artificial life
    Terzopoulos
  • Presenting the problem of building autonomous
    animated creatures for interactive virtual
    environments Blumberg
  • IMPROV a system for scripting interactive actors
    Perlin
  • Simulating crowds of ants in an automatic way
    PDI, PIXAR
  • Bugs Life 4466 different individual motions to
    describe 228 different behaviors

7
2. Related Work (2/2)
8
3. Crowd Structure (1/2)
  • Distributing the crowd behaviors to the groups
    and then to the individuals

9
3. Crowd Structure (2/2)
  • Two ways of setting the parameters
  • Scripted control defines scripted behaviors of
    the crowd
  • External control specifies guided behaviors
  • The intelligence, memory, intention and
    perception are focalized in the group structure.

10
4. Crowd Information (1/17)
  • Knowledge/belief/intention

11
4. Crowd Information (2/17)
  • Knowledge
  • Information of the virtual environment
  • the real position of a chair
  • concerns the memory of groups related to the past
    experiences as well as perception related to
    agents and groups.
  • Crowd obstacles
  • Crowd motion and action
  • Group Knowledge

12
4. Crowd Information (3/17)
  • Knowledge
  • Crowd obstacles
  • declaration of all objects of the scene
  • declaration of the areas where the crowd can
    walk.
  • declaring some regions where the crowd can walk
    with some obstacles to be avoided

13
4. Crowd Information (4/17)
  • Knowledge
  • Crowd motion and action
  • Described using goals
  • Goals IP AP
  • Individual AP
  • Shared AP
  • The agents from the same group share the same
    goals.
  • The paths for the different agents from the same
    group can be similar but are never the same
    because they cannot occupy the same sub-region.

14
4. Crowd Information (5/17)
  • Knowledge
  • Group knowledge
  • Memory
  • A structure where the leaders perceived
    information can be stored and processed
    afterwards depending on the specified behavioral
    rules ? The memory of groups is processed only
    by the leader of the group
  • The size of the memory (capacity of storage) can
    be pre-defined for each group of crowd.
  • Group perception
  • Some group associated parameters knowledge,
    beliefs and intentions
  • Location of groups/agents
  • Associated to just the leader of group

15
4. Crowd Information (6/17)
  • Beliefs
  • Emotion the list of behaviors to be applied by
    the groups
  • Can be shared or be redefined.
  • Crowd and group behaviors
  • High-level behaviors for crowds programmed in the
    script language or directly informed using guided
    control
  • 8 group behaviors
  • Flocking, following, goal changing, attraction,
    repulsion, split, space adaptability,
    safe-wandering

16
4. Crowd Information (7/17)
  • Beliefs
  • Crowd and group behaviors
  • Flocking
  • Group ability to walk together at the same speed
    towards the same goals
  • In real life, people walk in groups
  • Rules for flocking
  • The agents from the same group share the same
    list of goals
  • They walk at similar speeds
  • They follow the paths generated in Section 3.2.1
  • One agent can wait for another on arrival at a
    goal when another agent from the same group is
    missing

17
5. Crowd Information (8/17)
  • Beliefs
  • Crowd and group behaviors
  • Following
  • Group ability to follow a group or an individual
    motion
  • Permanent/temporary
  • Goal changing
  • Agents can have the intention of changing groups
  • The relationship with all groups
  • Its domination status

18
4. Crowd Information (9/17)
  • Beliefs
  • Crowd and group behaviors
  • Attraction
  • Groups of agents are attracted around an
    attraction point

19
4. Crowd Information (10/17)
  • Beliefs
  • Crowd and group behaviors
  • Repulsion
  • Groups ability to be repulsed from a specific
    location or region

20
4. Crowd Information (11/17)
  • Beliefs
  • Crowd and group behaviors
  • Split
  • The subdivision of a group to generate one or
    more groups

21
4. Crowd Information (12/17)
  • Beliefs
  • Crowd and group behaviors
  • Space Adaptability
  • Group ability to occupy all the walking space

22
4. Crowd Information (13/17)
  • Beliefs
  • Crowd and group behaviors
  • Safe-Wandering
  • Evaluate and avoid collision contacts with agents
    and objects

23
4. Crowd Information (14/17)
  • Beliefs
  • Emotional status
  • Subjective climate to be simulated
  • E.g. sad, calm, regular, happy,
    explosive
  • Parameters Way of walking, Walking speed, The
    range of basic actions
  • Emotion distribution
  • Emotional status can trigger an event.
  • Emotion can be changed as a function of triggered
    events and reactions

24
4. Crowd Information (15/17)
  • Beliefs
  • Individual beliefs
  • Basically, individuals are just able to walk
    whereas avoid collision with obstacles and other
    agents.
  • When the sociological effects are applied, its
    possible for the individuals to have a more
    complex structure of parameters including
  • Goal-changing behavior, group behavior (see
    Section 3.2.2.1)
  • A value for the relationship with all groups
    (between 0 and 1)
  • A value for its domination status

25
4. Crowd Information (16/17)
  • Intentions
  • Groups intentions
  • Goals and actions to be applied
  • Individuals intentions
  • Follow group or change of groups
  • Be leader dependent on domination value

26
4. Crowd Information (17/17)
  • Inter-Relationship among information

27
5. ViCrowd Architecture
  • Low-level behavior generation for each
    group
  • Modification of low-level behaviors of
    groups due to sociological effects
  • Modification of low-level behaviors of
    groups due to reaction triggering events
    (informed in the script language or by the
    external control)
  • Distribution of groups low-level behaviors
    to the individuals

28
6. Behaviors (1/8)
  • Programmed behaviors
  • Script language
  • To program specific behaviors in ViCrowd
  • To deal with three kinds of information
  • Geometric information
  • Behavioral information
  • Simulation information
  • To provide predefined commands to easily specify
    crowd behaviors

29
6. Behaviors (2/8)
  • Programmed behaviors
  • IPs and APs Generation

IP0 POSITION ( 1000 0 2500 ) ORIENTATION ( 0.87 0
0.4 ) ASSOCIATED_REGION 3 PTS ( 1300 0 5600 ) (
2100 0 4200 ) ( 1250 0 200 ) AP0 POSITION ( 1000
0 2500 ) ORIENTATION ( 0.87 0 0.4
) ASSOCIATED_REGION 2 PTS ( 1300 0 5600 ) ( 2100
0 4200 ) TYPE SHARED ACTION PARAMETERS KEYFRAME
applause
30
6. Behaviors (3/8)
  • Programmed behaviors
  • Crowd behavior generation

CROWD_SEMANTIC INTENTION PERCENTAGE 20 GOES TO
IP0 APPLIES AP0 PERCENTAGE 40 DOES
NOTHING BELIEFS EMOTION ALL HAPPY LEADER
PERCENTAGE 10 GROUP_BEHAVIORS ADAPTABILITY
PERCENTAGE 20 FLOCKING GROUP_5 SET
SOCIOLOGICAL_EFFECTS ON
31
6. Behaviors (4/8)
  • Reactive behaviors
  • Autonomous crowd
  • Crowd has the ability to react to events.
  • Event
  • can trigger a reaction.
  • Global events, local events, emotional events
  • ltwhengt, ltwhogt
  • Reaction
  • Contains the definition of the behaviors to be
    applied.
  • ltmotiongt, ltactiongt, ltinternal_status_changegt,
    ltposturegt, etc

32
6. Behaviors (5/8)
  • Reactive behaviors
  • Event
  • Reaction

event BUS_STOP WHEN CONDITION (Object_bus NEAR
IP_BUS) WHO ALL_GROUPS NEAR IP_BUS
Reaction TAKE_THE__BUS ACTION KEYFRAME
take_bus MOTION ATTACH Object_bus CHANGE_EMOTI
ON HAPPY
33
6. Behaviors (6/8)
  • Reactive behaviors

CROWD_STATUS PARTY PERCENTAGE 70
HUNGRY PERCENTAGE 30 SOCIAL
event HUNGRY WHO GROUP_STATUS HUNGRY WHEN
EVENT FOOD MATCHED reaction HUNGRY MOTION GO TO
TABLE / TABLE IP / ACTION INTERACTION SOBJ
TABLE
event CHANGE WHO GROUP_STATUS HUNGRY AND WHEN
INTERACTION SOBJ TABLE MATCHED AND REACTION
HUNGRY MATCHED reaction CHANGE GROUP_STATUS
SOCIAL
34
6. Behaviors (7/8)
  • External behaviors
  • Guided crowd
  • A client/server system to combine a Rule-Based
    Behavior System (RBBS) and ViCrowd
  • The RBBS is able to control groups or individuals
    by sending the information specifying what
    motion, action, event or reaction is to be
    applied.
  • Behavioral rules have a simple syntax

rule2 if ((Laura needs to take the train and
(Laura has no ticket)) then (Laura goes to
counter to buy one)
35
6. Behaviors (8/8)
  • External behaviors
  • Group memory
  • A guided behavior has priority over all scripted
    behaviors.

36
7. Results Discussion (1/2)
  • Simulations of crowds can be done in general
    virtual environments

(SB)(GB) (RB)
(SB)
(SB)(RB)
(SB)(GB)
37
7. Results Discussion (2/2)
38
8. Conclusions
  • The possibility of generating simulations with
    various levels of realism, including scripted,
    reactive, and guided behavior.
  • The hierarchical structure used to model crowds
    based mainly on groups instead of individuals.
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