PhysX

Common

NVIDIA's open-source real-time physics engine, and the physics core behind Isaac Sim and Isaac Lab.

PhysX is NVIDIA's real-time physics engine SDK. It traces back to NovodeX, founded by ETH researchers and commercialized in 2002; Ageia acquired and renamed it in 2004; and after NVIDIA acquired Ageia in 2008, it was rebuilt to use CUDA GPU acceleration, becoming dominant physics middleware in the game industry for years afterward. It was open-sourced under the BSD-3 license in December 2018, and the open-source version was upgraded to PhysX 5 in November 2022. PhysX 5 supports GPU rigid bodies, reduced-coordinate articulations (describing a robot by its root pose plus joint angles, so joints never “fall apart” — well suited to arms and legged robots), finite-element soft bodies, position-based-dynamics fluids and cloth, and signed-distance-field collision. It is the physics core behind Omniverse, Isaac Sim, Isaac Lab, and the earlier Isaac Gym; tuning solver iteration counts, friction, and similar parameters on those platforms is really tuning PhysX itself.

ExampleWhen training a robot arm to perform peg insertion in Isaac Lab, joint torques, contact forces, and friction are all computed by PhysX on the GPU; when interpenetration shows up, a common fix is to increase PhysX's solver position-iteration count.

Also called: NVIDIA PhysX, PhysX 5, PhysX SDK, NovodeX
Related: NVIDIA Isaac Sim · NVIDIA Isaac Lab · Isaac Gym · NVIDIA Omniverse · Articulated-Body Simulation (Articulation) · Newton Physics Engine
Sources: NVIDIA-Omniverse/PhysX (GitHub)
NVIDIA PhysX SDK
PhysX (Wikipedia)
As of: 2026-09