2015/07/07, by @TapirLiu

A list of open source physics engines

box2d.js. a JavaScript port of Box2D using Emscripten

Planck.js, another JavaScript port of Box2D, manually rewritten, not with Emscripten.

Box2DFlash. an ActionScript 3 port of Box2D 2.02 and 2.10 box2d-js is a JavaScript port of Box2D Physics Engine (converted from Box2DFlashA 1.4.3.1 in an automatic manner)

box2dweb is a JavaScript port of Box2D Physics Engine (converted from Box2DFlash 2.1a in an automatic manner)

wck (World Construction Kit ). a ActionScript 3 (using Alchemy) port of Box2D 2.10+

fbox2d, another ActionScript 3 port of Box2D 2.10+ revision 141.

pybox2d, a Python port of Box2D

JBox2D, a Java port of Box2D

Farseer, c#, based on Box2D

Box2D.go, a Go port of Box2D

go-box2d-lite, a Go port of Box2D-lite

dyn4j, 2d, Java

Cubez - a Go port

Nape, 2d, Haxe

Physijs (cannon branch), a physics plugin for three.js

GoblinPhysics, 3d, JavaScript

verlet-js, 2d, JavaScript, a simple verlet physics engine

PhysicsJS, 2d, JavaScript

Coffee Physics, 2d, CoffeeScript (compiles into JavaScript.).

JPE, 2d, JavaScript

Chipmunk2D, 2d, c

Walaber's JelloPhysics, soft-body physics dynamics (not found its webpage)

JelloAS3, an ActionScript port of JelloPhysics

JelloHx, a Haxe port of JelloPhysics, based on JelloAS3

Jello-Physics, a C# port of JelloPhysics

JelloSwift, a Swift port of JelloPhysics

Gravitle, 2D soft body engine, Rust

JigLib, 3d, c++ JigLibflash, an ActionScript 3 port if JlgLib

JigLibJS2, a Javascript port of JlgLib, based on JiglibFlash

Moby, 3d, c++, GPLv2

OimoPhysics, 3d, ActionScript 3

Oimo.js, a JavaScript port of OimoPhysics

elm-physics, a highly experimental toy physics engine in Elm language.

Traer Physics, a simple particle system physics engine for processing (language) and Java.

DynaMo, 3d, c++, GPL

React, a Java port of ReactPhysics3D

PositionBasedDynamics, 3d, c++, a library for the physically-based simulation of rigid bodies, deformable solids and fluids.

SPlisHSPlasH, 3d, c++, physically-based simulation of fluids

Here are some ones which may be not complete engines, but very good for study and education purposes:Along with these open sourced ones, there are some famous non-free (nor not universally free) ones:

Collision detection plays an important role in physics engine development. Here are some open source collision libraries:

In the end, some articles which are very helpful to physics engine development.

Game physics from scratch, maintained by Liam

This list may be not complete. Welcome anybody to help me improve this list.

[edit@2015/07/09] added Farseer, JBullet, ReactPhysics3D and React. Thanks to Nick Minkler and Danthekilla.

[edit@2015/07/10] added Chrono::Engine. Highlight GPL license ones. Added two non-free ones. Thanks to Morten Skaaning.

[edit@2016/09/12] added JPE. Bullet.js, Physijs. Box2DFlash, box2d-js, Chipmunk-js, LiquidFun, AmmoNext.

[edit@2017/01/21] added Velocity Raptor, Bounce.

[edit@2017/03/19] added Planck.js.

[edit@2018/01/04] added PyBullet, PositionBasedDynamics, SPlisHSPlasH, DMM. (Thanks electricslpnsld@HN for information)

[edit@2018/11/23] added elm-physics and Traer Physics.

[edit@2019/01/01] added dyn4j, Jitter Physics, BEPUphysics, cyclone physics, Cubez

[edit@2020/07/03] added Dyna-Kinematics and several Go ports of Chipmunk2D.

[edit@2020/07/03] added Rapier.