I'm currently making the physics engine for an action rpg. Here's the engine. You need Java and a gpu/igp that supports openGL. Spoiler: Controls Controls: -Enter pauses/plays the simulation -R resets the simulation -1, 2 & 3 selects a shape -A & D rotates the selected shape Spoiler: Feature checklist Feature checklist(not done, half done, done): -Rigid bodies -Cloth bodies -Fluids -Variable masses -Variable friction coefficients -Variable restitution (bounce) coefficients -Magnetism -Destructible rigid bodies (cracking, breaking) -Destructible cloth bodies (tearing) Spoiler: Update Log 02/02/2012 -Added different shapes -Made the screen bigger (800*600) -Under the hood changes 31/01/2012 -Functioning rigid body simulator Spoiler: Images If it closes on start up try changing the first word ("java") in the batch file to the path of your Java executable. Make sure to include the quotes around path. E.g. Change java to "C:\Program Files\Java\jre7\bin\java.exe"