Crowd simulation
Encyclopedia
Crowd simulation is the process of simulating the movement of a large number of objects or characters, now often appearing in 3D computer graphics
for film
. While simulating these crowds, observed human behavior interaction is taken into account, to replicate the collective behavior.
The need for crowd simulation arises when a scene calls for more characters than can be practically animated using conventional systems, such as skeletons/bones. Simulating crowds offer the advantages of being cost effective as well as allow for total control of each simulated character or agent.
Animators typically create a library of motions, either for the entire character or for individual body parts. To simplify processing, these animations are sometimes baked as morph
s. Alternatively, the motions can be generated procedurally - i.e. choreographed automatically by software.
The actual movement and interactions of the crowd is typically done in one of two ways:
, which are then animated by simulating wind
, gravity, attractions, and collisions. The particle method is usually inexpensive to implement, and can be done in most 3D software packages. However, the method is not very realistic because it is difficult to direct individual entities when necessary, and because motion is generally limited to a flat surface.
s - are given artificial intelligence
, which guides the entities based on one or more functions, such as sight, hearing, basic emotion, energy level, aggressiveness level, etc. The entities are given goals and then interact with each other as members of a real crowd would. They are often programmed to respond to changes in environment, enabling them to climb hills, jump over holes, scale ladders, etc. This system is much more realistic than particle motion, but is very expensive to program and implement.
The most notable examples of AI simulation can be seen in New Line Cinema
's The Lord of the Rings
films, where AI armies of many thousands battle each other. The crowd simulation was done using Weta Digital
's Massive software.
and crowd psychology
, often in public safety planning. In this case, the focus is just the behavior of the crowd, and not the visual realism of the simulation. Crowds have been studied as a scientific interest since the end of the 19th Century. A lot of research has focused on the collective social behavior of people at social gatherings, assemblies, protests, rebellions, concerts, sporting events and religious ceremonies. Gaining insight into natural human behavior under varying types of stressful situations will allow better models to be created which can be used to develop crowd controlling strategies.
Emergency response teams such as policemen, the National Guard, military and even volunteers must undergo some type of crowd control training. Using researched principles of human behavior in crowds can give disaster training designers more elements to incorporate to create realistic simulated disasters. Crowd behavior can be observed during panic and non-panic conditions. When natural and unnatural events toss social ideals into a twisting chaotic bind, such as the events of 9/11 and hurricane Katrina, humanity’s social capabilities are truly put to the test. Military programs are looking more towards simulated training, involving emergency responses, due to their cost effective technology as well as how effective the learning can be transferred to the real world. Many events that may start out controlled can have a twisting event that turns them into catastrophic situations, where decisions need to be made on the spot. It is these situations in which crowd dynamical understanding would play a vital role in reducing the potential for anarchy.
Modeling techniques of crowds vary from holistic or network approaches to understanding individualistic or behavioral aspects of each agent. For example the Social Force Model describes a need for individuals to find a balance between social interaction and physical interaction. An approach that incorporates both aspects, and is able to adapt depending on the situation, would better describe natural human behavior, always incorporating some measure of unpredictability. With the use of multi-agent models understanding these complex behaviors has become a much more comprehensible task. With the use of this type of software, systems can now be tested under extreme conditions, and simulate conditions over long periods of time in the matter of seconds.
3D computer graphics
3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...
for film
Film
A film, also called a movie or motion picture, is a series of still or moving images. It is produced by recording photographic images with cameras, or by creating images using animation techniques or visual effects...
. While simulating these crowds, observed human behavior interaction is taken into account, to replicate the collective behavior.
The need for crowd simulation arises when a scene calls for more characters than can be practically animated using conventional systems, such as skeletons/bones. Simulating crowds offer the advantages of being cost effective as well as allow for total control of each simulated character or agent.
Animators typically create a library of motions, either for the entire character or for individual body parts. To simplify processing, these animations are sometimes baked as morph
Morph
- Astronomy :* Morphs collaboration, a collaboration that studied the evolution of spiral galaxies using the Magellan and the Hubble Space Telescope- Biology :...
s. Alternatively, the motions can be generated procedurally - i.e. choreographed automatically by software.
The actual movement and interactions of the crowd is typically done in one of two ways:
Particle Motion
The characters are attached to point particlesParticle system
The term particle system refers to a computer graphics technique to simulate certain fuzzy phenomena, which are otherwise very hard to reproduce with conventional rendering techniques...
, which are then animated by simulating wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
, gravity, attractions, and collisions. The particle method is usually inexpensive to implement, and can be done in most 3D software packages. However, the method is not very realistic because it is difficult to direct individual entities when necessary, and because motion is generally limited to a flat surface.
Crowd AI
The entities - also called agentSoftware agent
In computer science, a software agent is a piece of software that acts for a user or other program in a relationship of agency, which derives from the Latin agere : an agreement to act on one's behalf...
s - are given artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
, which guides the entities based on one or more functions, such as sight, hearing, basic emotion, energy level, aggressiveness level, etc. The entities are given goals and then interact with each other as members of a real crowd would. They are often programmed to respond to changes in environment, enabling them to climb hills, jump over holes, scale ladders, etc. This system is much more realistic than particle motion, but is very expensive to program and implement.
The most notable examples of AI simulation can be seen in New Line Cinema
New Line Cinema
New Line Cinema, often simply referred to as New Line, is an American film studio. It was founded in 1967 by Robert Shaye and Michael Lynne as a film distributor, later becoming an independent film studio. It became a subsidiary of Time Warner in 1996 and was merged with larger sister studio Warner...
's The Lord of the Rings
The Lord of the Rings
The Lord of the Rings is a high fantasy epic written by English philologist and University of Oxford professor J. R. R. Tolkien. The story began as a sequel to Tolkien's earlier, less complex children's fantasy novel The Hobbit , but eventually developed into a much larger work. It was written in...
films, where AI armies of many thousands battle each other. The crowd simulation was done using Weta Digital
Weta Digital
Weta Digital is a digital visual effects company based in Wellington, New Zealand. It was founded by Peter Jackson, Richard Taylor, and Jamie Selkirk in 1993 to produce the digital special effects for Heavenly Creatures. In 2007 Weta Digital’s Senior Visual Effects Supervisor, Joe Letteri, was...
's Massive software.
Sociology
Crowd simulation can also refer to simulations based on group dynamicsGroup dynamics
Group dynamics refers to a system of behaviors and psychological processes that occur within a social group , or between social groups...
and crowd psychology
Crowd psychology
Crowd psychology is a branch of social psychology. Ordinary people can typically gain direct power by acting collectively. Historically, because large groups of people have been able to bring about dramatic and sudden social change in a manner that bypasses established due process, they have also...
, often in public safety planning. In this case, the focus is just the behavior of the crowd, and not the visual realism of the simulation. Crowds have been studied as a scientific interest since the end of the 19th Century. A lot of research has focused on the collective social behavior of people at social gatherings, assemblies, protests, rebellions, concerts, sporting events and religious ceremonies. Gaining insight into natural human behavior under varying types of stressful situations will allow better models to be created which can be used to develop crowd controlling strategies.
Emergency response teams such as policemen, the National Guard, military and even volunteers must undergo some type of crowd control training. Using researched principles of human behavior in crowds can give disaster training designers more elements to incorporate to create realistic simulated disasters. Crowd behavior can be observed during panic and non-panic conditions. When natural and unnatural events toss social ideals into a twisting chaotic bind, such as the events of 9/11 and hurricane Katrina, humanity’s social capabilities are truly put to the test. Military programs are looking more towards simulated training, involving emergency responses, due to their cost effective technology as well as how effective the learning can be transferred to the real world. Many events that may start out controlled can have a twisting event that turns them into catastrophic situations, where decisions need to be made on the spot. It is these situations in which crowd dynamical understanding would play a vital role in reducing the potential for anarchy.
Modeling techniques of crowds vary from holistic or network approaches to understanding individualistic or behavioral aspects of each agent. For example the Social Force Model describes a need for individuals to find a balance between social interaction and physical interaction. An approach that incorporates both aspects, and is able to adapt depending on the situation, would better describe natural human behavior, always incorporating some measure of unpredictability. With the use of multi-agent models understanding these complex behaviors has become a much more comprehensible task. With the use of this type of software, systems can now be tested under extreme conditions, and simulate conditions over long periods of time in the matter of seconds.
See also
- 3D computer graphics3D computer graphics3D computer graphics are graphics that use a three-dimensional representation of geometric data that is stored in the computer for the purposes of performing calculations and rendering 2D images...
- Artificial intelligenceArtificial intelligenceArtificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
- Emergent behavior
- Massive (software)
- Multi-agent systemMulti-agent systemA multi-agent system is a system composed of multiple interacting intelligent agents. Multi-agent systems can be used to solve problems that are difficult or impossible for an individual agent or a monolithic system to solve...
- Particle systemParticle systemThe term particle system refers to a computer graphics technique to simulate certain fuzzy phenomena, which are otherwise very hard to reproduce with conventional rendering techniques...
- Alice Software by the Moving Picture CompanyMoving Picture CompanyThe Moving Picture Company is a post production facility creating digital visual effects and computer animation for feature films, commercials, music videos and television...
- VISSIMVISSIMVISSIM is a microscopic multi-modal traffic flow simulation software. It is developed by PTV Planung Transport Verkehr AG in Karlsruhe, Germany. The name is derived from “Verkehr In Städten - SIMulationsmodell”...
- SpirOps
- Golaem CrowdGolaem CrowdGolaem Crowd is a plug-in for Autodesk Maya that allows for the simulation of controllable characters crowds based on independent agents. It is developped by Golaem, a France-based software company....
- Quadstone ParamicsQuadstone ParamicsParamics is traffic microsimulation software developed by Quadstone Paramics. Quadstone Paramics also develops pedestrian microsimulation software called the Urban Analytics Framework.-Background:...
- UAFUAFUAF may refer to:* University Admissions Finland* University Assistance Fund, Netherlands* University of Alaska Fairbanks, United States* University of Agriculture, Faisalabad, Faisalabad, Pakistan* Unite Against Fascism, United Kingdom...
- Enterprise DynamicsEnterprise DynamicsEnterprise Dynamics is a discrete event simulation software platform developed by INCONTROL Simulation Solutions. It is used to design and implement simulation solutions. The Enterprise Dynamics platform has several market-specific libraries to conform to customer requirements...
External links
- CrowdSimulation.org, Open discussion forum on crowd simulations
- CSG, Crowd simulation research.
- UNC GAMMA Group, Crowd simulation research at the University of North Carolina at Chapel Hill
- Crowd Tracking, Crowd tracking research in computer vision
- MASSIVE, the software used in The Lord of the Rings films.
- SpirOps Crowd, Crowd tool and AI middleware used in Splinter Cell - Double Agent game.
- Crowd Management Simulation, Crowd Management Simulation Application.