In context: PhysX is a moderately popular middleware used to add complex, physics-based interactions to 3D graphics in games and other software applications. Originally developed by the Swiss company NovodeX and later acquired by Nvidia, the technology is primarily designed to run on GeForce GPUs via Nvidia's proprietary CUDA software API.
Nvidia recently announced that its PhysX engine would become a fully open-source project. The developers have now released the source code under the permissive BSD-3 license and are inviting the community to experiment and tinker. Modders interested in keeping older games alive will likely benefit the most from this development.
Part of the PhysX SDK was already made open source in 2018, but Nvidia had withheld the source code for the GPU simulation kernel – until now. The latest update to the PhysX GitHub repository includes the complete kernel source code as well, giving the community a chance to turn PhysX into a truly "universal" gaming SDK.
PhysX now features over 500 CUDA kernels supporting advanced graphics capabilities, including rigid body dynamics, fluid simulation, and deformable objects, Nvidia explained. The open-source release also includes the full shader implementation of Flow, a more specialized development kit focused solely on real-time fluid simulation.
Nvidia noted that PhysX is one of the most advanced real-time simulation use cases of the CUDA API and GPU programming. With the new open-source release, developers can now build custom projects on top of these tried-and-tested foundations. In truth, however, PhysX never became a true standard for physics simulation in PC games due to its proprietary reliance on CUDA, which limited compatibility to Nvidia GPUs. Modern titles tend to favor alternative technologies that work across a broader range of hardware.
PhysX is supported in roughly 1,000 games, most of which require Nvidia GPUs to properly render advanced physics effects.
Complicating matters further, Nvidia removed official support for the 32-bit version of PhysX on its new Blackwell GPUs. Gamers quickly discovered that older titles such as Mirror's Edge and Borderlands 2 performed significantly worse on the GeForce RTX 50 series compared to earlier generations.
With the full source code now available, the community has a real opportunity to develop a working translation layer that brings 32-bit PhysX support to Blackwell and other GPUs.
Following Nvidia's confirmation of the API deprecation, some dedicated (and nostalgic) gamers have even opted to install a second, low-cost Nvidia GPU just to restore original PhysX performance on systems equipped with a newer RTX 50 card.
