Unreal Engine 5, [UE5 Developer Availability 2022-04-05]

[DavidGraham]

If unreal engine 5s lighting solution by default is lumen. What was unreal engine 4s default lighting solution?

Lightmass baked lighting, it's an offline rendering lighting solution, it affords you very few dynamic lights and/or dynamic shadows, you can do baked GI with it as well, or some screen space GI, you also have Screen Space and Planar for reflections.

UE4 supports a pretty capable Ray Tracing implementation for reflections and shadows, but global illumination is not good, as it mostly focuses on the indirect shadows portion of the illumination, missing the direct illumination and the light bounce, if you want those then RTGI becomes way too slow.

 

[davis.anthony]

Wasn't the PC port of Days Gone updated to have screen space GI?

I remember it looking very good.

 

[DavidGraham]

So according to DF's comparisons, SW-Lumen has more noise, due to it's low resolution (1/16 rpp), more light leaks, applies less or completely absent from skinned or dynamic, movable objects, and has shorter draw distance. Also, the reliance of Lumen on Surface Cache means that many reflections are still not perfect, they are really bad IMO with SW-Lumen, in HW they are reasonably OK, but still not to the level of the other RT reflections implementations even in UE4.

VSM has a problem with noise too, but that's probably to achieve 60fps on consoles. Resolution can drop as low as 846p on PS5/Series X in busy scenes, avg resolution is 60% (1296p) of 4K though.

HLOD is a problem though, it takes away from Nanite, as massive chunks of geometry/terrain stuff still pop in noticeably.

 

[Scott_Arm]

@DavidGraham On PC you can see very clear differences between medium and epic virtual shadow maps in terms of the resolution of the shadows. I just wish high option had shadows for the grass. I didn't notice it at first switching settings, but once it was pointed out to me the difference of the grass shadows does make the image have more depth. I'd just like some option with a little more performance that still had the grass shadows.

I might play around with disabling lumen reflections and using SSR instead, to see how much performance I can get back. I think the GI is the big winner, and I'd like to stay consistently above 120 fps. Unfortunately I seem to be cpu limited a lot on a 5600x, and I'm not sure if lowering the lumen settings will help.

 

[Andrew Lauritzen]

On PC you can see very clear differences between medium and epic virtual shadow maps in terms of the resolution of the shadows.

Yeah they are I believe >2x more resolution on Epic offhand. They are similar resolution to what they were in the Matrix demo when set to epic.

I just wish high option had shadows for the grass.

I "fixed"/changed that internally already. Some upcoming version will have contact shadows enabled on "high" as well as epic on PC.

Worth mentioning again that the grass never goes into virtual shadow maps - it is always contact (i.e. screen space) shadows only. For a variety of reasons (both performance and the look) it doesn't make sense for it to be a full dynamic shadow, and the screen space shadows can be softened in intensity a bit to simulate a bit of transmission; you almost never see completely black shadows from grass in reality.The size of the grass blades in games is typically expanded a bunch to add some arbitrary coverage which tends to create overly dark shadows as well.

I actually didn't realize until the DF video that the contact shadows are disabled on the series S. That may actually be intentional for performance reasons but could be revisited in the future too.

 

[Andrew Lauritzen]

VSM has a problem with noise too, but that's probably to achieve 60fps on consoles. Resolution can drop as low as 846p on PS5/Series X in busy scenes, avg resolution is 60% (1296p) of 4K though.

Yes indeed it's a mix of VSM and TSR actually. Some of the way that the upscaling happens creates some blocky artifacts that I'm sure we can improve on in the future (it wasn't really an issue in the past, but everything is constantly changing). Smaller %ges of upscaling will tend to minimize the artifacts in the mean time.

Some amount of the noise is harder to address in general though, particularly little slivers of light in interiors. That stuff really needs importance sampling or similar because in a lot of cases it's a tiny number of unoccluded rays, but the relative intensity of the sun combined with the tone mapping is making those few bits really bright. Problem for raytracing and everything else too, just shadow maps have conventionally not been high enough quality for it to be noticeable.

 

[Frenetic Pony]

Yeah they are I believe >2x more resolution on Epic offhand. They are similar resolution to what they were in the Matrix demo when set to epic.


I "fixed"/changed that internally already. Some upcoming version will have contact shadows enabled on "high" as well as epic on PC.

Worth mentioning again that the grass never goes into virtual shadow maps - it is always contact (i.e. screen space) shadows only. For a variety of reasons (both performance and the look) it doesn't make sense for it to be a full dynamic shadow, and the screen space shadows can be softened in intensity a bit to simulate a bit of transmission; you almost never see completely black shadows from grass in reality.The size of the grass blades in games is typically expanded a bunch to add some arbitrary coverage which tends to create overly dark shadows as well.

I actually didn't realize until the DF video that the contact shadows are disabled on the series S. That may actually be intentional for performance reasons but could be revisited in the future too.

SS shadows can have ugly artifacts at screen edges and other dissoclussions, it's definitely not a perfect solution. Considering the costs virtualized shadow maps don't seem like the "as many lights as you want" solution long term, even if there's some sort of lod between near virtualized and far cached RT.

 

[pjbliverpool]

I "fixed"/changed that internally already. Some upcoming version will have contact shadows enabled on "high" as well as epic on PC.

Both the fact that you can just do this, and the fact that it has been done, are awesome. The grass (and presumably other small object) shadows have a massive impact on visual quality, but the performance hit is also significant.

Thanks to the DF video I know the consoles use that setting, but I don't know whether they are using it at the equivalent of High, Epic, or something else entirely. I do know that my 1070 isn't over fond of Epic settings though.

On a side note, do you know why DRS isn't enabled on the PC?

 

[Andrew Lauritzen]

SS shadows can have ugly artifacts at screen edges and other dissoclussions, it's definitely not a perfect solution.

Indeed, but they look pretty good for grass. Not in the initial FN release but they will also be turned off for anything !grass when using VSMs in the future to eliminate most of those artifacts.

Considering the costs virtualized shadow maps don't seem like the "as many lights as you want" solution long term, even if there's some sort of lod between near virtualized and far cached RT.

Local light scaling is a bit of a separate question. You can definitely cache local lights a LOT more aggressively than the sun without any visual issues. That said, I do think once you start to think into the "actually many lights" future you're not going to have shadow map data for all of them... they need to be injected directly into some global data structure (Lumen or otherwise) at least for the distant/small ones.

 

[Andrew Lauritzen]

Thanks to the DF video I know the consoles use that setting, but I don't know whether they are using it at the equivalent of High, Epic, or something else entirely. I do know that my 1070 isn't over fond of Epic settings though.

Their resolution is closer to high IIRC, but consoles generally use their own set of settings. I don't remember if their filtering settings are closer to high or epic but I'd guess high as well.

On a side note, do you know why DRS isn't enabled on the PC?

I thought there was actually an option for it now, right? DRS in general on PC is a bit finicky because it's fundamentally a feedback loop algorithm and the fact that you don't have consistent/more deterministic timings and things like windows scheduling or another app using the GPU can hop in and do stuff out of your control without you knowing make it prone to doing bad stuff. There are some ways to mitigate that but it's definitely much more complicated on PC where you don't own the machine/GPU.

 

[pjbliverpool]

I thought there was actually an option for it now, right? DRS in general on PC is a bit finicky because it's fundamentally a feedback loop algorithm and the fact that you don't have consistent/more deterministic timings and things like windows scheduling or another app using the GPU can hop in and do stuff out of your control without you knowing make it prone to doing bad stuff. There are some ways to mitigate that but it's definitely much more complicated on PC where you don't own the machine/GPU.

Just checked and there's no option there for it right now. Although if you can "fix" that too I'm sure there'll be many a happy PC gamer!

Doesn't Windows have some option to allow the game greater/priority/exclusive control over the GPU? If it doesn't, it should. It doesn't seem like that difficult a feature to implement. "Windows Gaming Mode"...

 

[Andrew Lauritzen]

Doesn't Windows have some option to allow the game greater/priority/exclusive control over the GPU? If it doesn't, it should. It doesn't seem like that difficult a feature to implement. "Windows Gaming Mode"...

It will prioritize foreground tasks, but there are no guarantees, especially when you have multiple monitors. The issue isn't so much that other apps are *constantly* using the GPU, it's that even little spikes of them using it can mess up the feedback loop in unpredictable ways. This is just the nature of PCs - they are cool because you can run different hardware and applications and all that at the same time and have discord and streaming and browsers and video and things all going at once, but the generality does come with some costs of course. On PC you're generally better off finding a performance target you can consistently hit on your machine and lock the frame rate to that rather than trying to chase the last few % of dynamic quality IMO.

 

[Karamazov]

i remember reading that cars in the matrix demo where rendered with nanite until they took damage, then they switched to standard 3D model
so i checked RT reflections of a car before and after, we can see the standard model losing color reflections.

 

[Dampf]

Their resolution is closer to high IIRC, but consoles generally use their own set of settings. I don't remember if their filtering settings are closer to high or epic but I'd guess high as well.

I know you've probably heard that a lot already, but I really would like to see exact console settings for PC and DRS (that works with DLSS) as well. With my RTX 2060 laptop, I usually want to target console settings, but at 1440p or 1080p with upscaling. If the consoles are running at native 1440p and upscale it to 4K, my machine is usually fine at running performance mode at 1440p (so 720p internal) and get similar performance to the consoles, likewise if the consoles are running 1080p to 4K, I use performance mode at 1080p (540p). But of course, if consoles are dropping below the 50% value and/or are using custom settings I can't have on my PC, my machine is in trouble hitting my desired performance target. In this case with Fortnite getting below 50% on consoles, to get my desired performance target (60 even in the most heated battles and when flying over the map), I would have to set it to a fixed value of 40%, which would waste a lot of visual quality because my laptop usually would have enough headroom for 50-65% or better resolution scaling 95% of the time. That is why DRS would be super useful for me. I really hope you guys at Epic consider it now that you've heard a usecase for DRS on PC!

 

[SlmDnk]

Runtime Demo Redwood Forest UE5.1:

Download: https://www.mawiunited.com/_demo/rw1
Alternate1: https://www.mawiunited.com/_demo/rw2
Alternate2: https://www.mawiunited.com/_demo/rw3

Hardware requirement:

Minimum: RTX 2080
Recommended: RTX 3080

 

[Frenetic Pony]

Runtime Demo Redwood Forest UE5.1:

Download: https://www.mawiunited.com/_demo/rw1
Alternate1: https://www.mawiunited.com/_demo/rw2
Alternate2: https://www.mawiunited.com/_demo/rw3

Hardware requirement:

Minimum: RTX 2080
Recommended: RTX 3080

Can confirm from experience that this matches real life experience pretty solidly. Well, except for the snow, then again snow is the pretty much the ultimate material challenge. How exactly are you supposed to match a pile of highly reflective and translucent crystals in some arbitrary state of compaction and/or melting in realtime? Need to model like 50 bounces through an ultra dense, complex BSDF that presents pretty visible sub pixel geometric detail if it's close enough.

 

[orangpelupa]

Twinmotion to Unreal Engine Importer: bridging architectural worlds

Discover how this new plugin is set to create limitless opportunity for AEC firms.

www.unrealengine.com

Turns out twinmotion project can be imported into unreal engine!

Finally my dream of lazily creating vr games can be realized!


Goodbye 2d games projects! Hello vr games projects!

 

[Shifty Geezer]

Runtime Demo Redwood Forest UE5.1:

If we get this in a game, I'd consider this gen a full-bore next-gen evolution!

 

[Shifty Geezer]

Can confirm from experience that this matches real life experience pretty solidly. Well, except for the snow, then again snow is the pretty much the ultimate material challenge. How exactly are you supposed to match a pile of highly reflective and translucent crystals in some arbitrary state of compaction and/or melting in realtime? Need to model like 50 bounces through an ultra dense, complex BSDF that presents pretty visible sub pixel geometric detail if it's close enough.

Like everything else, approximate it with a mathematical model in a shader. At the level we see it, it's just a translucent mass with some randomised sparkles and noise.

 

[Frenetic Pony]

Like everything else, approximate it with a mathematical model in a shader. At the level we see it, it's just a translucent mass with some randomised sparkles and noise.

Unfortunately not, real life snow tends to look pretty weird and very obviously crunchy/fluffy, to the point where you can see the individual crystals from a decent distance away, the sparkle shaders we have now are a fantastically poor approximation. Not to mention how poor the heightfield hacks when walking through snow look.

There's been entire papers written on it, and researchers asked Disney for their snow physics sim from Frozen because it was the first accurate one they'd seen.