Sometimes people say that today’s games don’t measure up to the old ones and don’t offer much besides visuals. But what if modern visuals could be added to classic games that are even twenty years old? NVIDIA’s RTX Remix technology (or software) is supposed to do just that, making it relatively easy to add better graphics to even very old games using a mod – including raytracing effects and things like DLSS or DLAA. Let’s see how it works.
How to get ray tracing working in old games
Open Beta of RTX Remix and sources
RTX Remix is currently in beta and is already publicly available. You can download it here via the NVIDIA Omniverse tool, which you can then log into with your NVIDIA account and install the RTX Remix app from there. The RTX Remix runtime has a repository on Github.
NVIDIA Omniverse
Omniverse is a tool for collaboration of teams working with 3D graphics or CAD/CAM solutions, it can be used for example for organizing product development across continents and similar complex tasks, for creating digital twins of production plants or other objects, for industrial visualization, or for working with visual effects, as it supports integration with many important graphic tools and other software and applications. At the same time, Omniverse is also an SDK enabling the creation of new software with technologies such as raytracing graphics rendering and DLSS.
However, Omniverse can also serve as a simple app store-style platform for obtaining such applications, and the RTX Remix software is also distributed in this way, it can be easily downloaded via Omniverse after registering and logging in with an NVIDIA account (you don’t need a 3D headset for this, of course).
Installing RTX Remix from Omniverse is easy and straightforward, just be prepared for a relatively larger download which may take a while on a slow connection. The RTX Remix app obtained through Omniverse will allow you to start modding that game you get your eye on. It allows you to run it with an embedded (injected) RTX Remix runtime in order to analyze and catalogue the scene and objects, and work with the project files (rtx.conf profile for the game).
You can also use an rtx.conf profile that someone has already generated for a particular game and open it in RTX Remix mode for yourself.
The integration of RTX Remix into the entire NVIDIA Omniverse ecosystem is important because developers can use all of the in graphics and modelling tools and resources that support Omniverse interfacing, when modding games. And the collaborative features can then be used by developers to work together on modding and to pass on objects and components in progress. This was already demonstrated at the time RTX Remix was announced as the first demo showing a remastered scene from the The Elder Scrolls III: Morrowind game was created by a team working through Omniverse.
Mods: Big official projects and upcoming community remasters
Portal with RTX
In 2022, along with the RTX Remix tool and technology, NVIDIA also announced Portal with RTX, a remake of the iconic Portal game that was created using the RTX Remix tool and officially sponsored by NVIDIA (it was created by NVIDIA’s very own Lightspeed Studios).
Portal with RTX uses full ray tracing (i.e. they are not used just for select effects, but for rendering the entire scene) and all the new NVIDIA technologies: DLSS 3 upscaling, later also DLSS 3.5 with Ray Reconstruction, frame generation, and it has built-in support for Reflex technology to reduce latency. The game runs via the RTX Remix runtime on top of the Vulkan API (in 64-bit mode).
Portal with RTX has not only had ray tracing “added” to it, it has also seen extensive improvements to the game’s components at the model and texture level. Textures have physical characteristics that allow for realistic reflections and scattering of light and shadows, as well as increased resolution. The models are also more realistic with a high polygon count and new details, but the team working on them has kept their original silhouettes, so it’s a subtle change that doesn’t disturb the original character of the game.
Thanks to full ray tracing, the game has realistic lighting (including ray-traced volumetric lighting) as well as the associated shadow rendition, which should be fully realistic without tricks or simplifications. NVIDIA RTX Direct Illumination (RTXDI) and NVIDIA Reservoir Spatio Temporal Importance Resampling Global Illumination (ReSTIR GI) technologies are used, which allow games to use more direct and indirect light sources than what was viable before.
The original game had limited lighting using spot lights, but in Portal with RTX this is reworked and the game is redesigned with more light sources of different types and intensities (including the famous companion cube, for example).
As you’ll see in the screenshots, this significantly changes (and improves) the face of the game. Fans will be pleased to know that light and shadows travel and reflect even through all off the iconic portals in the game thanks to this. The implementation of ray tracing is more advanced than in Quake II RTX or Minecraft with RTX, with new techniques employed. Rays are reflected up to four times instead of just once. The demands on hardware are expectedly higher for this reasons, so DLSS and Frame Generation are important for playability on today’s GPUs.
Portal: Prelude RTX
Last year, NVIDIA added another part in the form of Portal: Prelude RTX. It’s a release that adds better visuals and full raytracing to the most popular mod of the original Portal, which is called Portal: Prelude and dates back to 2008. Prelude is an unofficial prequel to Portal with 19 levels by Nicolas Grevet (Nyk0018) and other authors.
Portal: Prelude RTX also uses full ray tracing with realistic shadows and lighting that has been manually redesigned. New higher quality models and textures with physical properties are used here as well, allowing for realistic reflections, mirror image effects and light scattering.
To improve performance, DLSS 3.5 support has again been integrated, including Ray Reconstruction (Portal: Prelude RTX was the first of the remakes to premiere the feature) and Frame Generation, as well as Reflex for improved latency. But the game also uses RTX IO, so it can take advantage of the highest-performance NVMe SSDs for faster texture loading with less load on the CPU, while also reducing the space taken up by the game on the hard drive. RTX IO is always active, no need to turn it on separately.
This mod again requires you to have the original Portal in your Steam library, after which you can get it for free. You can find it here.
Portal with RTX and Portal: Prelude RTX: future potential in mature form
Created directly with official support and with sufficient resources and development time, these modifications are now the best demonstration of what RTX Remix technology offers and enables. This makes them technological demonstrators and a kind of reference or benchmark of what can be achieved with RTX Remix.
And at the same time, these games are fully mature for consumption, so if you’re interested in the visual qualities of ray tracing, they’re the perfect choice for trying it out. Other modifications, which are created by a community of enthusiasts on their own, haven’t had a chance to get that far in the limited time available, so they’re more of a future potential. So if you want to try out what RTX Remix can do, the ideal place to start is with Portal with RTX and Portal: Prelude RTX.
Half-Life II RTX is also coming
Portal: Prelude RTX won’t be the last official remake NVIDIA will embark on, though. Last summer, the company announced the Half-Life 2 RTX project, which will be a similar remastered version of the game with full ray tracing, new textures and more detailed models, and support for new technologies. Again, virtually all of the game’s assets are to be improved.
The game is now in development under the Orbifold Studios banner, which is supposed to be a collaboration of four of the best modders for Half-Life II, so the modding community will be involved this time. On NVIDIA’s website, you can already see some previews of the game’s redesigned environments, which show that the game will be transformed quite dramatically, with some models of machines, computers and other props recreated from the ground up in modern detail.
It is not yet known when this remastered Half-Life II RTX game will be released.
Max Payne RTX ON Demo
The modification of this well-known game is also not yet finished, but it should reportedly be one of the more successful and relatively complete demonstrations, and is probably the furthest along of the fan projects in demonstrating the capabilities of RTX Remix technology. Several enthusiasts are working on it, and the goal is to make a large elaborate modification of the game. You can find it here.
The modification has to be installed on top of an existing installation of the full version of May Payne (a demo is not enough), but the process is a bit more complicated. You need to download the RTX Remix files using this downloader, copy them from the created folder to the Max Payne folder, then install Microsoft’s DirectX 9c runtime into the Max Payne folder and then a community patchset for the game and when using new processors, including AMD Ryzens, this patch fixing JPEG decoding in the game is required.
The developers state that the game should not be installed in Program Files x86, but somewhere else on the drive with unrestricted access (so that Windows don’t interfere trying to protect the folder from unauthorized write access). It is also recommended to removesecondary monitors. In case of problems, using the -skipstartup option, installing Visual C++ Redistributable, and also running in windowed mode instead of full screen (or disabling full screen optimizations and running the game as an administrator via Windows compatibility mode) can further help.
The original Tomb Raider (Open Lara RTX: Reimagined Realms)
Another modification that has surfaced is a remake of the first game in the Tomb Raider series, created by Aureate Games. It is called Open Lara RTX: Reimagined Realms, as it is a fork of the Open Lara Project mod. The original Tomb Raider is a game running under DOS, so RTX Remix could not be used on it directly.
This mod adds full ray tracing (path tracing) to the game, but like other similar projects it is not yet complete. You can download the demo, however, in which the first two levels are remixed. In addition to ray tracing and new lighting, the game also has some new textures and models (such as enemy animal models).
This mod can be downloaded from here, and as a baseline you need to own and have installed the original game from either Steam or GOG (but perhaps the original game data folder from a CD should work as well). It has a very user-friendly installer that even finds the folder with the installed game itself, and in this case the installation should be really easy (the RTX Remix files are already included). Indeed, on our test PC with a GeForce RTX 4080 Super, the installer worked flawlessly on the first try and basically just took a few clicks.
We had a different problem, ironically: While the mod was running fine, the original game failed to launch. The GOG distributed game uses DOSbox and stubbornly kept crashing despite our efforts, both in standard mode using the wrapper translating the original acceleration via 3Dfx Glide and with software rendering. We were not able to resolve the issue in the time available, sadly.
Grand Theft Auto: San Andreas
The popular GTA V won’t be able to be remixed due to RTX Remix limitations allowing only DirectX 9 and DirectX 8 games, but one very popular modification target could be Grand Theft Auto: San Andreas originally from 2004. The GTASA RTX Remix Project mod is in the works, which can be found on GitHub.
However, if you want to see the results in the current state of this modification, you will face a rather challenging installation. As always, you’ll need to have the original base game, ideally downgraded to version 1.0, furthermore you need manually downloaded RTX Remix files. But the mod files themselves are distributed via GitHub, so you’ll need to clone the repository with a tool (such as GitHub for desktop) and manually copy the files. After that, it is still recommended to install a number of other mods and patches for stable operation.
Therefore, after we struggled with a not so easy process with previous games, we didn’t test this mod for time reasons.
Greater selection
However, a larger number of these modifications are already in the works. A “showcase” catalogue of games that someone has plans to modify or at least experimented with can be found on the RTX Remix Discord here (it’s probably likely that some of these projects will be abandoned before completion, but on the other hand there may be others competing projects or other enthusiasts dealing with yet other games).
On ModDB you can also find a list of mods that are already available for download in some demo version or are in the process of being modified, or a list of RTX Remix compatible or semi-compatible games if you want to experiment with the development side of the thing.
Our experience
Most of the unofficial mods (if not all, since open beta access only started this January) for RTX Remix are not finished and you may encounter various issues when installing them and trying to get them running. For example, some reports say you are likely to run into problems if you use a laptop or desktop with both integrated and dedicated GPUs (and a hybrid graphics card). Users also report that their games sometimes start running only after uninstalling the OpenCL, OpenGL, and Vulkan Compatibility Pack, which you can have installed in Windows 11 (you can find it in the Microsoft Store, not in the classic list of installed programs and components). There can also be problems on computers with multiple monitors.
Modifications probably only see limited testing and debugging currently, so successful installation and launch is not a guaranteed thing. For example, we couldn’t get Open Lara RTX: Reimagined Realms to run on a second PC with a Radeon graphics card and Windows 11 (it’s hard to tell if it was a problem with that PC or the mod, but after launching the program remained stuck with no further response). But as we mentioned, on the main test PC this modification ran perfectly and installation was easy and without complications (which is far from the case with the other mods we tried).
With the Max Payne mod, we were almost lucky, but ultimately ended up empty-handed. We managed to get it up and running in shape sufficient at least for the purposes of performance testing after a bit of tinkering, but the visuals were flawed with a faulty final color rendering. Apparently all the rendering of objects and scenes was otherwise fine except for the output on the monitor. Because of this error, however, we could not use the mod for image quality comparisons.
It must be said, however, that for many people these modifications work out of the box, so don’t take away too much pessimism from that. Remember that open beta access for RTX Remix only started this January, so we are only at the beginning stage of community projects creating RTX modifications. In the future their demos will definitely be more stable and easier to use, the RTX Remix runtime itself will of course undergo development, and the sophistication of the remastered content itself will of course only be fully appreciated in time.
But you don’t have to worry about such pains with the official Portal mods (Portal with RTX, Portal: Prelude RTX) and the future Half-Life II mod, because they are developed and distributed by a professional team of many heads, unlike mods that are made by enthusiasts who don’t have a surplus of human resources. This of course will also be reflected in the high quality visuals, new models and textures that have been created for these games.
The Portal games can thus serve as an ideal demonstration of what can be achieved with RTX Remix technology, while the unofficial modifications often produced by single dedicated enthusiasts will be more about the skills and time of the creators.
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