Portal with RTX launches a new revolution in legacy ray tracing

Portal with RTX is an absolute victory, not only for its ingenious use of lighting and cutting-edge technology, but also in how it works – bordering on black magic. This new version of the Valve classic is built on a new framework from Nvidia called RTX Remix, which basically hijackes old PC games built on a fixed function rendering path, and replaces the raster with a full path trace. Motion vectors have been added, opening the door to TAA, DLSS, and even per-object motion blur support.

“Remix” suggests a certain level of user adjustability and that’s exactly what’s possible, and it displays beautifully in Portal. With render replacement, lights can be bypassed, assets can be replaced with newly created replacements and textures can be made or reconfigured to be physical. It is a complete system of replacing game images with pathfinding that lives entirely outside of the game’s awareness and gameplay code. It’s honestly amazing that this works at all – and Portal with RTX shows what Remix can do when time is invested in creating new assets and customizing every area and asset in a game to work with the new rendering model.

On a basic level, what sets track tracking apart from RT in most games? Titles like Cyberpunk 2077 or Marvel’s Spider-Man Remastered still do rasterization but add RT effects for elements like reflections, shadows, ambient occlusion, or global illumination. In Portal with RTX, ray tracing takes over pretty much everything previously rendered with rasterization. All initial rendering is ray-traced, which only makes it more expensive initially. However, it does offer some good cost advantages: All glass can be refractive due to the initial rays of vision bending when they interact with the glass, giving it the appearance of the corrugated surface you see in real life. Rays can be traced through titular portals without the quality degradation seen in the original version of the game.

Portal with RTX also tracks all direct lighting as well, giving shadows and highlights in real time – something completely missing in the original. Objects that move now have shadows that move with them, particles receive lighting from their surroundings, and emitting surfaces such as cues emit light dynamically, whereas in the original game the lighting remained constant no matter what happened. The Portal with RTX tracks all indirect lighting as well, using four bounces on the ultra setting by default. This is why the reflections look so much better than in a hybrid ray tracing game: the light bounces off the reflections, giving them much better shading. This is also why Portal with RTX can look very different from the original in many scenes.

Tying together this new lighting are new assets for the textures and geometries that populate the game world – and this difference is significant on closer examination. Assets that were originally limited by the geometry and texture capabilities of the GPU in 2005 now have incredibly detailed surfaces, while some textures are replaced with full geometry. Portal wasn’t quite a high-end game in terms of texture or engineering quality when it came out in 2007, but it now rivals the texture and engineering quality we’re seeing in titles released in 2022. This has proven oddly controversial, so if you don’t like it or any Other changes are you can always replace the texture yourself if you want to, or if you don’t like the new assets (which I have no idea why you don’t), you can convert in the RTX Remix game options which can be accessed by pressing ALT and X.

In terms of performance, current internet wisdom says only RTX 4000 GPUs can run at a playable frame rate, which is both true and false. To run the game on Ultra settings at higher resolutions at 60fps or higher, a new Ada Lovelace card is definitely required. I played the game without DLSS 3 frame generation using 4K DLSS performance mode on an RTX 4090 with Core i9 12900K, max 60fps. He only dropped two frames while winning the entire game. I thought it was excellent, but of course I’m relying on DLSS 2 image reconstruction here. Native 4K is a rip off in terms of performance – simply because of the massive amount of RT processing the game has to offer.

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Portal powers its super setup with the largest path tracing ever put into a video game: it uses four initial bounces with no back-end build cheating, so your GPU will feel humbled by it. However, you can also make your PC more ready to boot by tweaking the settings and using less DLSS mode than you might be used to. Choose the High preset, set the maximum amount of track bounce to two and reduce the quality of the stutter and you’ll keep the lion’s share of the visuals, while the performance is radically improved. On top of these recommendations, I also recommend keeping volumetric lighting on as it can greatly enhance the atmosphere. I’d also suggest keeping the textures to ultra-light, and also setting the particle lighting to ultra-light which provides crisp particle lighting at a small performance cost.

For older Ampere or Turing cards at the bottom of the stack, choose High settings and set the maximum amount of light bounce down to one (for the record, one light bounce is equivalent to what Quake 2 RTX does). You can also experience lower-than-expected DLSS settings – the 4K Ultra Performance mode looks very good, likely due to its clean art style and because the game has a few very thin transparencies that cause some problems in lower DLSS modes. Obviously, resolution has the biggest impact on performance, so be reasonable in what you aim for and don’t shy away from DLSS.

I’d say there’s a path to decent performance on almost any Nvidia RTX card — I had decent results even on the RTX 2060 Super — but the same can’t be said for AMD. Radeon GPUs are less impressive in RT performance than their Nvidia counterparts, but the experience here is simply smashed and given that the game doesn’t even launch on Intel GPUs, Nvidia needs to work here to ensure a decent experience for all capable users. hardware. The implementation of DLSS 3 frame generation also needs to be improved as with or without v-sync it will never feel smooth. The frame rate gain is as high as it should be, but the camera movement presents shake issues and rubber bands – which is why I stuck with DLSS 2 for my games.

In short, I think Portal with RTX is great. The new lighting model breathes life into an old game I would never have revisited – and it made me appreciate Portal even more for not being constrained by the technical limitations of the Source engine. This is what RTX Remix will do for many titles when it’s fully released – people online have already added Portal RTX Remix files to games like Max Payne, SWAT 4, and more and even without replacing assets, RTX Remix works so magically that’s hard to believe. Just imagine what it can do when users have complete control over their micron grains – we’re going to have a revolution in ray tracing and I can’t wait to see the results.

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