Unity 3d Physics Engine

The Physics Engine of Unity 3D

What is Unity 3D 3

What is a Physics Engine 3

Physical variables 4
rigid bodies 5
collision detection 6
joints 7
cloth & hair 9
ragdolls 10

Nvidia PhysX 10
Sources 12

What is Unity 3D?

Unity 3D is a multiplatform game engine. With Unity3D you are able to develop games for PC, Web, Xbox360, Playstation3, Wii and all mobile devices (e.g. iOS, Android and Windows Phone 8).
The Unity Game Engine is used by a lot of developers because it has a lot of features and it is
pretty easy to handle.
Unity 3D is downloadable for free but can be upgraded to Unity Pro which offers a lot more features and a faster rendertime.

What is a Physic Engine?

A Physic Engine is a Computer Software, that simulates the principles of Physics. The description Physics Engine is normally used for a application, that calculates physical laws and displays them.
The Physics Engine is calculated via the Physics Processing Unit (PPU) that is nowadays located on every Graphics Card and it relieves the Central Processing Unit (CPU) from computationally intensive tasks.
The calculations can be done in realtime or with a really high precision, that cannot be calculated in realtime. The high precision applications need a really high computing power and are normally only used by scientists, whereas the realtime calculation is used for computer games.

Physics in computer games is getting more and more important. If objects and players behave physically correct, the overall gaming experience enhances.

Before I go into detail about a physics engine, there are some fundamentals to explain.
What is Physics and what does it mean?

Wikipedia describes it in the following way:

"Physics is the natural science that involves the study of matter and its motion through space and time, along with related concepts such as energy and force. More broadly, it is the general...