From Halopedia, the Halo wiki
|There is more information available on this subject at Havok (software) on the English Wikipedia.
Havok is a proprietary software suite developed by Havok. The software has been used by numerous projects, both in the video game and movie industries.
Integration into the Halo development
Havok Physics is a physics engine used to provide dynamic simulation to simulate physical interactions realistically, including such features as ragdoll physics or intelligence in massive falling objects. The engine was first utilized in Halo 2 and has remained one of the key component software in the Halo development ever since.
Halo: Combat Evolved is the only Halo title that utilizes Bungie's in-house physics engine.