Crytek has announced that the CryEngine is now available to everyone for free, including the full source code !  The latest version launched today with a "pay-what-you-want" business model and  with no obligation to pay royaltie …

https://github.com/NvPhysX/UnrealEngine The CPU-based implementation of PhysX 3.3.3, including the clothing and destruction libraries. Source for NVIDIA PhysX can now be found as part of the Unreal Engine code on the GitHub netw …