NVIDIA’s RTX Remix: The Revolutionary Modding Platform

BY Asif

NVIDIA, the world leader in visual computing technologies, has recently launched RTX Remix, a modding platform that will remaster classic DirectX 8 and 9 games with path tracing, NVIDIA DLSS, AI-enhanced textures, and user-created assets.

RTX Remix is a part of the NVIDIA Studio suite of apps and is composed of two core components that work together to enable modders to remaster classic PC games: the RTX Remix creator toolkit and a custom RTX Remix runtime.

The RTX Remix creator toolkit, built on NVIDIA Omniverse and used to develop Portal with RTX, allows modders to assign new assets and lights within their remastered scene, and use AI tools to rebuild the look of any asset. The RTX Remix creator toolkit Early Access is coming soon.

The RTX Remix runtime captures a game scene and replaces assets at playback while injecting RTX technology, such as path tracing, DLSS 3 and Reflex, into the game. Mod developers have been using the RTX Remix runtime from Portal With RTX to create experimental ray traced scenes in numerous classic games.

To further empower the mod development community to extend Remix’s game compatibility and feature set, NVIDIA is releasing the RTX Remix runtime as open source on GitHub today. The RTX Remix runtime is open source with a permissive MIT license and includes the following components:

• USD capture and replacement modules, responsible for capturing a game scene to USD, and replacing original game assets with modded game assets at runtime.
• Bridge, which translates the renderer from a x86 to a x64 instruction set. This component uncaps the memory available for rendering.
• Scene manager, which uses information coming through the D3D9 fixed function API to create a representation of the original scene, track game objects frame to frame, and set up the scene to be path traced.
• The core path tracer, which includes the rendering loop, the material handling, and the game-specific rendering features (e.g., decals and particles).

Open sourcing unlocks numerous possibilities to extend the feature set of the Remix runtime. Mod developers can make more of their favorite games compatible with Remix, modernize the fluid simulation to render smoke and fire with realistic volumetrics, inject custom post-effects shaders in the runtime, add animated lights, replace animated character meshes, change camera positions in games, incorporate virtual reality support into the renderer, and implement dynamic conditional replacements (e.g., add fog or change a light in response to a player’s position).

Several Remix engineers have joined the community-led RTX Remix Showcase Discord server and are providing guidelines on compatibility and responding to mod developers’ questions about RTX Remix. Modding is all about community, and providing an open source RTX Remix runtime will help empower mod developers to expand Remix compatibility to even more classic PC games.

For PC gamers, an open source RTX Remix runtime will help broaden the variety of games with RTX mods and the types of mods themselves. The possibilities are endless, and we look forward to seeing what mod developers will build with source access.

If you are looking to get started with your own Remix runtime open source project, head over to the RTX Remix Showcase Discord to find subject matter experts to collaborate with. NVIDIA will accept pull requests on Github for code submissions from the community, provide feedback, and help advance code until it is mature enough to be merged into the official RTX Remix runtime.