User:Hj224/sandbox

= Crowd simulation  = Crowd simulation is the process of simulating the movement of a large number of entities or characters; this technique is now commonly used in 3D computer graphics for film. While simulating crowds, observed human behavior and interactions are taken into account to replicate collective behavior.

Here's an interesting video demo of Crowd simulation https://www.youtube.com/watch?v=3wjCwtc_-hk.

= Technology and model =

Modeling of crowd motion
Each person is the object of simulation-particles, and the crowd is considered as a large particle system. Particles can communicate with other; however, a set of particles correspond to a group of specific people with the same behavior patterns. Particle systems create a simple and useful model of crow simulation which can conveniently solve the simulation of obvious characteristics and abstract crowd movement. 2. Push and limb collision began to happen between individuals.
 * Simulation Model of Crowd Movement Based on Particles
 * Simulation Model of Crowd Evacuation Movement in Panic State
 * 1) In panic state, crowd try to move faster than the common situation.

3. When crowd cross the narrow, the movement becomes disorder.

4. People from all directions accumulate at the exit.

5. A blockage becomes to form.

6. The collision between individuals exacerbated and pressure may exceed the warning line.

7. The rate of evacuation was further slowed down by individuals who fell or were injured

8. Bandwagon effect happened

9. During the evacuation, some of the exits were ignored by the population or not well utilized.

Although the model simulates the evacuation movement of specific situations, but it has high authentic value and therefore simulates different kinds of phenomenons in such situation. Providing a efficient solution for construction workers to think about. ViCrowd model defines the set of three layers, which is crowd, group and agent. Then it defines the attributes of people relate to Knowledge, Beliefs and intentions.
 * ViCrowd Movement model

Crowd behavior modeling
There are two categories for crowd behavior modeling.

The first category treats the crowd as a collection of homogenous individuals which react to the events and environment according to some simple rules.

Example: Particle system model

The second category treats the crowd as a collection of heterogeneous individuals that are empowered with significant decision-making capabilities like real human.

Example: Agent-based model

And most agent-based models are composed of:

(1) numerous agents specified at various scales (typically referred to as agent-granularity); (2) decision-making heuristics; (3) learning rules or adaptive processes; (4) an interaction topology; and (5) an environment.

Crowd AI
Entities – also called agents – 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. Entities are given goals and then interact with each other just as members of a real crowd would. They are often programmed to respond to changes in their environment; for example, they may climb hills, jump over holes, scale ladders, etc. This system is much more realistic than particle motion, but it is very expensive to program and implement.

Software
Miarmy Golaem
 * Miarmy (read My Army) is a Human Logic Engine based Maya plugin for crowd simulation, AI & behavioral animation, creature physical simulation and rendering.
 * Golaem makes it easy and affordable to populate worlds with smart & directable digital characters, from a few to thousands.

Crowd evacuation

 * It is one of the most dominant applications of crowd simulation for safety science and architecture design. The goal of such applications is to suggest people how to evacuate crowds safely and efficiently when emergency (such as fires and earthquakes)occurs, and help designers to assess risk and optimize the safe design of architecture space.

In Film production

 * The emphasis is primarily on high-quality rendering and animation techniques to achieve convincing visual effects

Reference
[1] Dirk Helbing, IIIes Farkas, Tamas Vicsek, Simnature, 2000, July 487-490.

[2] Bouvier, E.; Cohen E.; and Najman. L. "From crowd simulation to airbag deployment: particlesystems, a new paradigm of simulation". Journal of Electronic Imaging 6(1), 94-107 (January 1997).