Physics engine

A physics engine is a computer program that simulates Newtonian physics models, using variables such as mass, velocity, friction and wind resistance. It can simulate and predict effects under different conditions that would approximate what happens in real life or in a fantasy world.

Description

There are generally two types of physics engines, real-time and high precision. High precision physics engines require more processing power to calculate very precise physics and are usually used by scientists and computer animated movies. In video games, or other forms of interactive computing, the physics engine will have to simplify its calculations and lower their accuracy so that they can be performed in time for the game to respond at an appropriate rate for gameplay. This is referred to as real-time physics. Computer games (especially racing games) use physics engines to ensure realism. Recently, there has been increased interest in the reality of the physics engines in games. This may be the result of advancing processor speeds, allowing the game developer to use realistic physics to add a new level of game play while still creating a stunning graphical environment, along with increasing expectations of consumers.

Physics based character animation in the past only used rigid body dynamics because they are faster and easier to calculate, but modern games and movies are starting to use soft body physics now that it is possible. Soft body physics are also used for particle effects, liquids and cloth.

Physics Processing Unit (PPU)

February 2006 saw the release of the first physics processing unit from Ageia, which functions like a graphics card, taking the weight of physics processing off the CPU. The unit was most effective in accelerating particle systems; the performance improvement for rigid bodies was modest.

General Purpose processing on Graphics Processing Unit (GPGPU)

GPGPU is another promising approach for real time physics engines, including rigid body dynamics. ATI and Nvidia provide rigid body dynamics on their latest graphics card. ATI claims |X1900 XT should deliver 9 X the performance of an Ageia PhysX card

See also

• Game physics
• Ragdoll physics
• Procedural animation
• Rigid body dynamics
• List of physics-based games

Real-time physics engines

Open sourced:

• Open Dynamics Engine
• Bullet
• OPAL

Closed sourced:

• Newton Game Dynamics - A free, but closed source physics engine
• Tokamak physics engine

Commercial:

• Havok
• PhysX (formerly NovodeX and incorporaring Meqon)
• Newton Game Dynamics - A free, but closed source physics engine
• nV Physics SDK
• Endorphin, an animation tool that combines physics and AI with genetic algorithms

High precision physics engines

• Mechanica from Parametric Technologies Corporation.
• Working Model, from Design Simulation Technologies. (2D only).
• Falling Bodies, from Animats. (Ragdoll physics).

External links

• PhysicsAndMathLibrary This library is royalty-free for hobby use and an inexpensive alternative for commercial developers.
• The Physics Engine The Physics Engine is a new effort in games/animation physics simulation.
• Newton Game Dynamics Newton is a free physics engine for commercial and hobby use, supports multiple platforms, SDK is contained as well.
• PGNX Physics, a versatile physics engine with haptic capabilities
• Open Dynamics Engine
• Bullet Physics Library Open Source, free for commercial use collision detection and rigid body dynamics library.

Racing physics:

• FastCar Library
• Atlas F1 technical forum
• Automotive engineers area on eng-tips.com
• Racer Free Car Simulation Physics and Racing Physics and Maths forums at rscnet.org
• Ageia PhysX Graphics Card