NVIDIA RTX Remix is a platform that allows easier modification and improvement of the visuals of old games, which includes not only updating individual assets (models, textures, etc.), but also adding modern technologies such as ray tracing/path tracing or DLSS. It uses for its operation NVIDIA Omniverse, which is a collaborative platform that was originally created primarily for use in industry to create digital copies of all kinds of structures and systems. At the beginning of 2022, however, it was made available to individuals as well, on the basis of which various companies began to develop new tools and services. In this context, the terms USD and Nucleus are often encountered. What is it about?
USD (Universal Scene Description) = universal file format to facilitate work across different 3D content creation programs. It contains information about the layout of objects in the scene (scene layout), about the geometry and materials of objects, about animations, virtual cameras, etc., see the video presentation of Nvidia about USD. This format was created by Pixar (a studio specializing in the creation of animated films), which published it as open source in 2016.
The goal is that something created in a program with a focus on a certain area (eg Autodesk Maya, Autodesk 3ds Max, Blender, Adobe Substance 3D Painter, Unreal Engine, Unity) can be seamlessly transferred to another content creation program using application linking ( referred to as a connector) while maintaining the parameters defined at creation. E.g. the Unreal Engine connector is available as of 2020.
Nucleus = a database system that is used by the Omniverse platform and serves as a central cloud data storage. Thanks to it, multiple people can work on the same files at the same time, where everyone can see the current version in real time, while there is also file versioning to be able to go back to earlier versions and access rights management to be able to set different permissions to ensure the necessary workflow.
What games can be improved in RTX Remix?
Among the basic prerequisites of RTX Remix is that the game uses the interface DirectX 8 or DirectX 9 and worked with objects using a method called “fixed function pipeline”. Titles that require an older or newer version of DirectX cannot use the RTX Remix platform (or not in the current version, as this may change over time).
Compared to standard code modifications for adding new technologies or changing game assets, the modder does not need to have the source code of the game available, which is a big advantage. Instead, it launches the game, through RTX Remix, in simple terms, scans the running game world and creates a configuration file with information about what to change after launch with this configuration file, and what assets to replace with others, before the final rendering and display on the image output (monitor).
– click to enlarge, RTX Remix Runtime –
It is more about creating a new configuration profile of the game, when new information is inserted (injected) as part of the rendering process. The advantage of this procedure is the fact that the functionality of the game mechanics is not changed, so the modified version of the game created in RTX Remix should not affect what happens in the game, what information is saved, or how it is played (unless, of course, the graphics changes made have a direct influence on the gameplay itself, which will be an example of a different intensity of location lighting, when something was more visible before RTX modifications, or vice versa). To create better versions of textures, AI can also be used directly within RTX Remix to simplify the work.
In the past months, we have already covered two specific projects using RTX Remix in articles. The first was the release of the already completed Portal: Prelude RTX remaster, which was created in cooperation with NVIDIA (it is an unofficial prequel to the first part of Portal, the RTX version of which was released a little earlier). And then we had the announcement of the Half-Life 2 RTX community remaster in progress.
At the same time, NVIDIA made the RTX Remix platform available to the public as an open beta on January 22, 2024 (see its accompanying article for details). Shortly afterwards, on February 6, an update to the latest version 0.4.1 was released. If you want to try RTX Remix yourself, you will need one of the GeForce RTX graphics cards and a user account with NVIDIA (to play modified games using RTX Remix, a card from NVIDIA is no longer necessary, however, the question is how it will be with the performance of chips from other manufacturers) . Subsequently, the following videos explaining the basics of working within the application interface could help you:
Although relatively little time has passed so far, a number of modders have already started trying out what RTX Remix has to offer. We’ll list examples that NVIDIA also uses to demonstrate RTX Remix, and then we’ll look at a few examples of other game mods from various modders.
Ways of implementing ray tracing
Before we focus on modifications with RTX Remix, we will pause on the ray tracing technology itself. The first graphics cards with HW support for real-time ray tracing (RT) were based on NVIDIA’s GPU architecture called Turing, whose first chips were introduced in 2018 (GeForce RTX 20 series), see our overview of desktop graphics chips. After its introduction, game titles with RT support gradually began to appear, while at the beginning they were updates of already released games that added RT, for example, only to reflections or shadows, which did not have much effect on improving the overall visuals. In addition, the reflections were sometimes overdone to demonstrate the new technology (it can look impressive on metal armor, but it can be distracting on floor material).
But it was only a matter of time before titles appeared that offered ray tracing as well global illumination (Global Illumination, X-ray), which is what can significantly affect the overall visuals, see the following examples of newer games using RTGI. An illustrative and very detailed video from Digital Foundry focusing on Metro Exodus Enhanced Edition serves well to explain the influence of RTGI. The example of the game The Witcher 3: Wild Hunt for the Next Gen update application is also interesting, see our earlier article (the RTX Remix platform was not used in these cases):
In connection with RTGI, it also began to be used path tracing, which is another method using the principle of ray tracing, in which, simply put, the light sources have a greater effect on their surroundings as a result, and the label “full ray tracing” is used for it (see the explanation of the difference in the presentation of DF). The influence of path tracing can be seen not only in modern games such as Cyberpunk 2077 or Alan Wake 2, but for illustrative purposes games with very simple graphics will serve well, where a mere change in the method of global lighting will stand out more, as can be seen in examples of the use of path tracing in Minecraft game modifications and Doom (the RTX Remix platform was not used in these cases):
It should also be mentioned that a similar result can be partially achieved by using a post process effect screen space shader (e.g. using ReShade) which is referred to as SSRTGI. The advantage of such a solution is simpler implementation and lower performance requirements. But the disadvantage is that only what is currently visible on the screen is taken into account, and not the data that is outside it, so not only is the result not so accurate, but also all kinds of strange behavior occurs in the propagation of light depending on from which angle we look at what, see illustrative examples in this video:
