They said in UE5 Nanite presentation, they need to change technology for terrain rendering.
Unreal Engine 5, [UE5 Developer Availability 2022-04-05]
- Thread starter mpg1
- Start date
They said in UE5 Nanite presentation, they need to change technology for terrain rendering.
So there's Dampf's answer. Full RT isn't posislbe on console so a simplified tracing model is used which can't be used on HWRT. This relegates HWRT to spot effects, although hopefully it's still used (if not now, eventually) such as tracing shadows.
That might become an opiton later in the future.
The thing with RT is it has the overhead of building the acceleration structure regardless of how few surfaces/pixels actually request any raycasts. So for a conservative "special case" use of RT to be feaseble for high performance games, the dev would ideally have fine control over what assets and at what LOD go into Acceleration Structure, and perhaps carrwfully manage that list per area/section of the world, etc. Kind of how the few games that use plannar reflections extensively do.
Project Gray - (supposedly UE) - via DSOG
Very impressive demo for a single person studio, especially the wind effects.
Stupid Aliens though, all that space technology and they still can't defend themselves properly in a fight
Very impressive demo for a single person studio, especially the wind effects.
Stupid Aliens though, all that space technology and they still can't defend themselves properly in a fight
Starting to all make sense now, SW-RT for the “absolute fastest tracing possible” and HW-RT for more cinematic projects. Seems like software is much faster and would make sense why they used software instead of hardware for the Lumen in the land of nanite demo. Just the wording a couple months ago made it seem like HW-RT was an unlocked upgrade and would be the default from here on…sad that’s not the case, sucks they are keeping SW-RT.
Really curious to see how much of a penalty if they use HW-RT on that lumen in the land of nanite demo.
Really curious to see how much of a penalty if they use HW-RT on that lumen in the land of nanite demo.
I was enabling it in the project Valley of the Ancient a year ago or so and the framerate tanked bad.
But then someone, maybe even here on this forum, gave me a command that disabled something and performance went back to how it was before. HW-RT kept working but the performance was good again. Maybe this command is the key to keep HW-RT being performant when there's a lot of overlapping meshes.
If SW-RT is faster for something, why does it suck that they're keeping it? HW-RT for the sake of HW-RT, just like any other tech for the sake of itself, is nonsense.
DavidGraham
Veteran
SW-RT in UE5 lacks reflections, accurate scene-wide GI, and soft shadows, so it's only faster in one case: generic GI (combined with screen-space information) with overlapped (hobbled together) geometry, the moment you ask any advanced technique out of it, HW-RT becomes the vastly fast and superior choice.
But the Matrix demo gave the impression that it had proper HW-RT implrmentation on consoles. My character and the scenery and non visible objects moving in the background were properly reflected on reflective surfaces.
Also I think proper GI was present
DavidGraham
Veteran
The Matrix demo used HW-RT for GI, reflections, and character shadows on consoles. On PC it had even more accurate and higher levels of GI and reflections.
So it is possible then. Where is this SW-RT coming from then? The implementation was pretty good even if it was not as high resolution as on a PC
Also seen here at 3:50 PS5 version.
DavidGraham
Veteran
SW-RT in UE5 uses approximation of GI (by combining screen space with software traces, no GI for skinned meshes, no reflections, no shadows for area lights), it is used to make your game 60fps on consoles. The Matrix demo has strong GI which is applied to all surfaces (including skinned meshes), reflections all over, and shadows for area lights, it used HW-RT to do all of that, and as such was only limited to 30fps.
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DavidGraham
Veteran
Let's be real here, it's not about the fps here, it's about the features: SW-RT can't do reflections, or area light shadows, or GI for skinned meshes, or large scale accurate GI, if a game has any of that, it will use HW-RT instantly, SW-RT will disable all of those image quality features, and thus will run the game at Medium settings.
The Matrix demo will look ugly as shit in 60fps mode, all off screen reflections will be gone.
Effectively running the game at Medium Settings, disabling reflections, shadows, and higher IQ GI. This is no different than playing Cyberpunk without ray tracing on an RTX 2070.
I see no reason for you to get that upset.
Lumen in the Lands of Nanite was a demo built to be a Nanite stress demo, it had lots and lots of overlapped kitbashed geometry, so it represented the worst case for HW-RT, games are not built that way.
In ‘The Matrix Awakens’ tech demo on consoles, the cost of both tracing methods is nearly the same. Hardware Ray Tracing gives higher quality reflections and supports GI over huge view ranges with Far Field, so it was the better choice.
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It's wrong to think of it as software RT and hardware RT - it's more "simplified traced lighting" and "full RT". Simplified traced lighting doesn't map to the hardware as I understand it which is why it's run on CPU, but as it's simpler, it runs faster than full RT running on RT HW.
Raytraced shadow are only used during cutscene. Shadows are using virtual shadow maps during the demo itself and raytraced AO. I think GI use software raytracing but higher quality with mesh SDF tracing and reflections only used HW-RT. Settings for console is Epic for Matrix Demo.
EDT: 60 FPS only use Global SDF tracing
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