A few years ago, CD Project Red has licensed Havok physics engine and animation system for upcoming game titles. As result, the highly acclaimed The Witcher 2: Assassins of Kings title was using Havok based physics.
As company’s next generation REDengine 3 was announced, it would be natural to expect that future games utilizing this engine, such as The Witcher 3: Wild Hunt, will continue to rely on Havok technology.
However, in a recent interview with PCGamesHardware, it was revealed by the developers that PhysX SDK will be used in The Witcher 3 as the physics engine (and this was confirmed by our sources as well). In addition, NVIDIA APEX integration will provide additional features such as cloth simulation and realistic destruction.
As of yet there is no information if GPU acceleration will be supported by The Witcher 3 or if other CD Project Red projects, like Cyberpunk 2077, will use PhysX based physics too.