The Newton Physics Engine, (or Newton Game Dynamics) providing a physics library for real time simulations of physics environments for Windows, Mac, iOS, and Linux recently posted the engine as Open Source. Check out the Newton physics engine page for more information and download links.
Newton Game Dynamics is an Open-source zlib-licensed integrated solution for real time simulation of physics environments. The API provides scene management, collision detection, dynamic behavior and yet it is small, fast, stable and easy to use.
“Our engine implements a deterministic solver, which is not based on traditional LCP or iterative methods, but possesses the stability and speed of both respectively. This feature makes our product a tool not only for games, but also for any real-time physics simulation. You can integrate Newton Game Dynamics into your projects with ease. With our technology you only need to know basic physics principles to produce realistic physics behavior. Tuning time is reduced to a minimum because you don’t need to wrestle the targeted hardware nor set up esoteric parameters to get the correct timing for your simulation.”