Today, NVIDIA has readied a big surprise called Portal: Prelude RTX for PC gamers. Designed as the latest showcase title for RTX Remix, Portal: Prelude RTX will be available on Steam starting at 12 PM PT as a free download to all owners of the original game.

　　It is a community remaster of Portal: Prelude, the fan-favorite award-winning mod for Valve's game. It's the first game made by modders who had early access to the RTX Remix creator toolkit, and it was designed to leverage all of NVIDIA's cutting-edge technologies: path tracing, NVIDIA DLSS 2 and 3 (which boost performance by 5X at 4K and max settings, according to NVIDIA, allowing 80+FPS on RTX 4080 and 4090 GPUs), NVIDIA Reflex, and NVIDIA RTX IO. The long-awaited suite of GPU-based loading and decompression technologies debuts here, delivering 5X faster texture load times in Portal: Prelude RTX and reducing occupied disk space by 44%.

　　On top of that, the remaster packs a challenging 8-10 hour campaign composed of 19 new test chambers, new advanced gameplay mechanics, and a fully voiced story with NPCs.

　　Wccftech has the scoop on Portal: Prelude RTX and all its features, thanks to a chat with Nyle Usmani, Product Manager for RTX Remix at NVIDIA. As a side note, there's a new Game Ready driver available for download today, optimized for this RTX remaster.

　　What was involved in adding RTX to Portal: Prelude RTX?

　　We developed RTX Remix to make it easy to turn RTX On in classic games. Using RTX Remix, all of the geometry, textures, and lights from Portal Prelude were converted to USD (the universal scene descriptor file format) and then imported into the application to be further modified. Every asset in the game was either ported into Portal: Prelude RTX from Portal With RTX or remade by the mod team by hand via Omniverse connected applications like Blender. In total, the mod team made hundreds of new props and textures for this remaster, all gorgeously rendered with physically accurate materials and immense detail for 4K gaming.

　　RTX Remix includes a custom D3D9 runtime that can act in place of the D3D9 runtime that the game ships with–this allows us to replace the old rendering APIs and systems with RTX Remix’s 64-bit Vulkan ray traced renderer. This enables the addition of path tracing to classic games and it all updates in real-time as lights and objects move. Light can be cast from behind the player or from another room, and in Portal: Prelude RTX, light even travels through portals. Glass refracts light, surfaces reflect detail based on their glossiness, objects can self-reflect, and indirect light from off-screen illuminates and affects everything you see. DLSS 3 allows us to target an incredibly accurate simulation of light while keeping the experience smooth and FPS high.

　　On top of the graphical changes, Portal: Prelude RTX also includes updated gameplay and fully voice acted dialogue, making this the definitive way to play the game.

　　How many people worked on this project?

　　It was a surprisingly small team. We actually reached out to the original creator of the Portal Prelude mod, Nicolas “Nyko18” Grevet and talked him into coming out of modder retirement and spearheading the project. He partnered with well-known modder David “Kralich” Driver-Gomm. The mod team behind the remaster was five people in total, including two voice actors from the mod community.

　　How much time did it take from start to finish?

　　The team of five people had Portal: Prelude RTX completely remastered in less than eight months.

　　Does Portal: Prelude RTX support Ada Lovelace's hardware path tracing optimizations, like Shader Execution Reordering (SER), Displaced Micro-Mesh (DMM), and Opacity Micro-Maps (OMM)?

　　Portal: Prelude RTX uses the newest version of the RTX Remix runtime, which includes superior denoisers and improvements to CPU and GPU performance for existing path tracing techniques.

　　For Portal: Prelude RTX and future NVIDIA RTX Remix mods, the NVIDIA RTX Path Tracing SDK has been enhanced, improving denoiser performance and quality. This is particularly beneficial at lower resolutions, where gamers with older GeForce RTX GPUs can have a better experience.

　　Portal: Prelude RTX supports Shader Execution Reordering (SER). SER dynamically reorganizes inefficient ray tracing workloads into considerably more efficient ones, further accelerating GeForce RTX 40 Series performance. This leads to better efficiency and eventually better performance.

　　Opacity Micro Meshes (OMM) increase real-time performance and memory compression for complex geometry, further accelerating GeForce RTX 40 Series ray tracing performance, and with new CPU optimizations debuting in Portal: Prelude RTX, players receive even faster performance.

　　NVIDIA DLSS 3 and NVIDIA Reflex also make an appearance in Portal: Prelude RTX but have both been upgraded to their newest versions for improved performance, even better image quality, and more responsive gameplay. The game also features NVIDIA RTX IO, enabling incredibly fast loading.

　　The rest of the tech is pretty consistent with Portal With RTX.

　　Portal: Prelude RTX is the first game to feature RTX IO. What is RTX IO exactly?

　　RTX IO is a suite of technologies that enables rapid GPU-based loading and asset decompression with optimizations through our Game Ready Driver for both the DirectX and Vulkan APIs. RTX IO is based on GDeflate, an open GPU compression standard contributed by NVIDIA, which is utilized by both Microsoft’s DirectStorage and new Vulkan Extensions. Portal: Prelude RTX leverages the new Vulkan Extensions.

　　NVIDIA RTX IO delivers up to 5X faster texture load times in Portal: Prelude RTX and utilizes 44% less disk space! This is a huge boon to modders as they can design their assets in the highest fidelity while taking up a smaller footprint on people’s hard drives.

　　Does Portal: Prelude RTX only work on NVIDIA GPUs?

　　Portal: Prelude RTX uses Vulkan ray tracing and should run on any Vulkan RT-capable graphics card. We’ve optimized the game to ensure a good experience on all RTX GPUs, but Portal: Prelude RTX is best experienced on RTX 40 Series GPUs with DLSS 3 due to how intensive and cutting edge path tracing is.

　　So NVIDIA RTX IO works on AMD and Intel GPUs, correct?

　　Yes. If a developer implements RTX IO, they get cross-platform support for DirectStorage and Vulkan.

　　Does RTX IO use tensor cores?

　　No. RTX IO leverages the open standard GDeflate, which is designed to run on as many parallel cores in the GPU as possible. GDeflate is an open GPU compression standard contributed by NVIDIA.

　　Is RTX IO compression lossy or lossless?

　　GDeflate is lossless.

　　How is the work on the RTX Remix creator toolkit coming along? Do you have an ETA to share on when it might enter early access?

　　Nicolas Grevet and David Driver-Gomm are the first modders to receive the RTX Remix creator toolkit. We will be expanding the group of modders with early access soon.

　　What do you think about the community's creations since you released the RTX Remix runtime?

　　We love it. There is a community-run Discord group where 5,000 modders are utilizing the RTX Remix runtime to remaster over 80 games. The degree of passion we’ve already seen is mindblowing, and I’m struggling to grasp what they’ll produce when we finally put the creator toolkit in their hands. We encourage anyone interested in RTX Remix mods to join the “RTX Remix Showcase” Discord group and take a look.

　　Can creators expect increased stability for mesh hashes in future versions of RTX Remix?

　　One of the earliest changes we implemented with the runtime was improving our mesh hashing system to increase stability–it is something we are always keeping our eye on. RTX Remix is groundbreaking tech in that visuals and assets are being replaced on the fly at playback but it's always unfortunate when something breaks and a new asset fails to render at full fidelity or as a replaced asset.

　　We can confirm our new runtime allows for much more stable meshes in Portal: Prelude RTX than was present in Portal with RTX and due to the speedup in asset streaming with RTX IO, assets load in at full quality at lightning-fast speeds.

　　Will there be any way to improve particle physics and/or smoke, for instance, at some point?

　　We had predicted when we open sourced the RTX Remix runtime that modders might contribute code to the runtime that could modernize fluid simulation for smoke and fire. So far, there hasn’t been a community effort on this front. We do find this space interesting but have nothing to announce today.

　　What about a potential scripting language to add new functionality to games?

　　It would be cool to enable scripting for dynamic conditional replacements. For example, make the lights turn off when a user enters a room or add fog in a room when a certain asset flies in.

　　As of now, we have nothing to announce, but it’s the kind of addition we predicted could happen when we open sourced the RTX Remix runtime.

　　Do you plan to improve the accessibility of using RTX Remix?

　　The RTX Remix runtime is open source and available for anyone to dig into. We are always working to make the tool as easy to use as we can. And for those who want to dive deep, we are very active in the aforementioned community run Discord and are always keeping an eye on projects that are evolving quickly.

　　Again, we encourage anyone interested in RTX Remix mods to join the Discord group.

　　Is there anything else you wish to add about what's next for this tool?

　　We are hyper focused on getting the RTX Remix creator toolkit available to more people as soon as we can, and we can’t wait to see what modders do when they get their hands on it. We hope everyone enjoys playing Portal: Prelude RTX, the first mod made by the community with early access to the RTX Remix creator toolkit. It’s a sign of what’s to come with respect to RTX Mods that push the graphical horizon.

　　Thank you for your time.