I have a requirement to meet … no temporal accumulation.
This means no TAA or TSR, though it would be straightforward. Unreal has several AA solutions … but um … it seems every lighting feature of Unreal is just desperately dependent on temporal accumulation, e.g. it’s noisy as hell unless you finish up with TAA or similar.
What am I missing? Is Unreal simply locked into noisy half-solutions that get cleaned up with temporal blurring?
Not a trolling spicy question, I assume the answer is there, and I am just overlooking it, but so far, not finding a lighting solution, even using a baked static main light that doesn’t produce sparks and noise without TAA
Surface/volumetric lightmaps, distance field shadows, cascaded/regular shadowmaps, reflection captures, planar reflections… none of them do any temporal accumulation. SSAO optionally uses temporal accumulation to amortize the cost but can be disabled and looks basically the same, same for SSR. SSR does have some dithering patterns when used without TAA though.
Megalights and the old RT shadows can be effectively brute forced by raising the sample count but well… it costs a lot and for megalights you’ll need to limit the amount of overlapping lights because it still spreads the samples out over the number of lights affecting the pixel.
I turned off all ray tracing, disabled GI and reflections, baked lights, and I still get a ton of noise in shadows, and transparent things look horrible.
I’ll keep poking at it, if you have a sample somewhere I can look at I can’t find even a sample that is both noise-free and not using TAA/TSR
Alternatively you can just switch to forward shading, since it doesn’t support any of the features that use temporal accumulation anything that is causing noise will be automatically disabled. (except any materials you have created that are reliant on temporal dithering)
Okay so there is a LOT wrong in this scene but
But you can see the noise in the shadows and the sparks on for example the knee of the character
This is just a rendering test nothing more so I have been poking at it and making quite the mess but that is the problem I am always seeing when TAA is not used
As to things I have tried
Disable raytracing everywhere
Forgo GI and Reflections
ShadowMap not Virtual
No post process at all
Simplify the lights … just 1 baked direct light + sky
Everything I try has zero effect on the sparks and the noisy shadows
I gotta be honest I can’t see anything in this, I don’t see anything on the knee… compression was brutal to this video. Honestly might be better to just take a screenshot and circle the areas that are having problems. Or perhaps try to upload it as an attachment here instead of on dropbox.
I will say that if this is a character is based on a metahuman or something made by Epic, they use the DitherTemporalAA node heavily in their materials. Especially for hair.
High frequency normals can also sometimes cause bright flashes of specular highlights.
Probably the best example of UE without TAA (by Epic) would be Robo Recall. It’s for UE4, all the features are still in UE5. Unfortunately I am not sure the content for it is accessible anymore, but there are live streams of how they built everything. Sadly I can’t think of anything more recent.
Just so you know, having no post processing volume does not mean you have no post processing. Just means that you’re using the defaults. It shouldn’t matter in this case, as I assume you’ve disabled Lumen/Megalights/Raytracing via project settings already so they don’t need to be set in the post process volume.
Yes, I am aware, I mean, I went through and disabled adaptive exposure, bloom, colour correction, etc.
I’ve been testing a range of content. That video was just a test on a more complex character and environment; it’s just a few “Paragon” assets from FAB.
The constant moving noise in shadows like static on a CRT TV … if you remember that :D, such as under the foliage and behind transparents, and the sparkles (bright points) you catch in what should be shadow in a few spots. That’s what I was getting at.
I am making a bit more progress with my latest settings,
The image here has much cleaner shadows, no blur even in a screengrab mid frame with her rather twitching animations … much cleaner. I am finding Virtual Shadow Maps add noise. This is mostly noticeable on soft shadows and with ambient occlusion so I still need to see what I can do there.
VSM relies on temporal accumulation for a form of raytracing (SMRT) in the penumbra if you have soft shadows enabled. Look at the VSM docs for more details, but this can be disabled for sharp, noise free shadows. However they will be so sharp that you will see visible stair-stepping.
Looks like you are also seeing dithering in the material. Paragon character materials were authored with TAA usage in mind. They generally don’t use real transparency, so the wings and hair of that character will be using dithering. Those materials would need to be adjusted.
It seems in UE5, you’re effectively forced into using Lumen for lighting in most modern projects. While baked lighting workflows exist, they are limited and don’t give you access to the majority of UE5’s renderer features.
Using Lumen means lighting is fully dynamic, which introduces instability in shadows. To smooth out this noise, you are effectively forced to use temporal accumulation solutions like TAA or TSR. This comes with trade-offs:
TAA/TSR smooths shadow noise, but introduces edge blur, which is detrimental to painterly or crisp stylised art.
Sharpening post-process can reintroduce artefacts.
Reducing TAA/TSR intensity preserves clarity but allows flickering/shadow noise.
In short, there seems to be no current UE5 solution that provides clean, crisp, painterly-style shadows without either noise or blur, unless you abandon Lumen entirely and commit to a fully baked lighting approach.
I’m specifically looking for a setup that allows:
Stable, soft shadows
Crisp edges suitable for a stylised painterly 3D aesthetic
Preferably, baked lighting is acceptable for this workflow
If anyone has found a reliable workflow for this in UE5.7 or knows of any undocumented solutions, I’d love to hear about it.
Quite a bit with the out-of-the-box materials but we could live with that
Quite a bit of the post-processing effects AO in particular, is giving me issues; again can probably live with this
Reflections, which I am less worried about, but the SS reflections are not usable as far as I can see … this is a bit poop but I can workaround it with my own solution.
VSM is leaving us with CSM, which is frankly looking horrible so far, still tweaking to see if I can smooth out some of the blockiness. This is hard to live with CSM is just so god awful with the setups I have tried so far.
The fact that no mixed-mode works with static baked + movable is a huge hit that invalidates partitioned worlds as a viable feature for us … shame, but fine, I can work around that with streamed levels
Fog … just … man its bad
In short, UE 5.7 seems to be really hardcore leaned into Lumen + TAA/TSR, which paints us into a corner for what we were hoping to do visually … which I find odd … isn’t SMAA new? why add it if lighting is pretty trash without Lumen, and Lumen makes shadows trash without accumulation? Maybe a pure mobile thing, not really leveraging typical lighting setups?
We could live with most of that … if we could manage decent soft-baked shadows while still supporting basic dynamic/movable lights of keen importance… we can’t have the noisy shadows. I mean, we are throwing out hugely useful tools that depend on TAA because of the edge blur; we can’t accept noise in shadows or lack of soft shadows as a trade-off.
Still holding out hope to find an approach that works, but it’s looking more and more like we’ll have to change our visual requirements or change the engine for this project. We aren’t after photo-real so it’s not like we need the heavy lift UE can do … we do need “clean” visuals, and while I am sure it’s not impossible with UE … it seems to be a hell of a fight to sort out.
Okay, you seem to be confusing baked lighting with forward shading. Most of the new features don’t work with forward shading, that doesn’t have anything to do with baked lighting.
SSR, all post processing effects, VSM, Nanite, World Partition, etc. They all work with baked lighting. SSR/VSM/Nanite and any post process effect requiring gbuffers require deferred shading.
Mixed moveable/static has always worked, in both forward/deferred no idea why you would think it doesn’t.
The only feature I am aware of that doesn’t work with baked lighting in 5.7 is Substrate. Everything else should work as long as you are in deferred shading.
Em, no, we are testing Differed… we have also tested forward, but that was early out, seen as to limiting
So right now we are trying to define a different path without using Lumen or VSM, but managing clean, noise-free soft shadows, mixing baked directional and dynamic/movable points here and there
SSR, quality is poor but I have managed so far, again, I can work around this
no quite a few of the post-processing settings behave much cleaner with Lumen + TAA than without no Lumen
VSM in particular introduces noise just in and of itself, but the alternative CSM … poor quality
World partition is limited because there is no mixed mode lighting e.g. we have to bake the lighting data for direct light … fine, but we cant stream in lighting data e.g. we cant have the world data be persistent and have 2 different lighting setups baked that we can swap out we have to dup the whole map which … ouch … easier to just go back to a classic streamed level with terrain on a persistent level and have streamed levels deal with the lighting
Also with baked lighting you can actually use planar reflections which are the highest quality reflection method Unreal has.
If all else fails you can get the same quality as Lumen reflections by just… using lumen reflections. They can be combined with baked lighting. They don’t need to accumulate for mirror surfaces and will fall back to captures on rough surfaces.
What does this mean? What are these mysterious features that require Lumen?
This has nothing to do with baked lighting, VSM relies on temporal accumulation to handle soft shadows. CSM quality is excellent, you just need to be conscious of how far you spread your resolution. Soft shadows can be done for local lights without any noise by using distance field shadows.
Leave the directional light dynamic and bake only the lights that actually need to be baked?
It seems like what you meant to say is that “non-TAA workflows exist, but exclude most of Unreal’s modern features” That would be a correct statement. Baked lighting does not exclude anything (except substrate) but if you want features that require doing a lot of samples, which almost all the new features require, you need some kind of temporal filter.
In short, UE 5.7 seems to be really hardcore leaned into Lumen + TAA/TSR
I am trying to find a way to have my cake and eat it to … there are workflows that “work” they are … as I said prior
I think I have enough data, though, to put it up the chain for them to pick … change the style, change the engine, or fist fight UE
TSR is at least not as offensive as TAA is with the muddy look, wish it could be tuned in editor for easier, faster adjustments, but I personally think Lumen + TSR > Baked Hell > Lumen + TAA mud … for our target look anyway
I mean, you also said lightmaps locked you out of most modern rendering features, so hopefully you will not hold it against me for thinking you meant something else.
Regardless, yes, Lightmaps are complicated to work with and they require designing your environments around its limitations. The complexity and numerous idiosyncrasies of baked lighting is why Lumen was designed the way it was; Heavy temporal filter and all. So that artists could just throw stuff in the scene and have it “just work” without having to know every minute detail of how Lightmass operates and consider every edge case when designing a level.
Personally, I think lightmass is still worth it for the majority of projects. Obviously, not everybody is gonna want to deal with it though.
If it were a bit less cumbersome (for me) I would agree I prefer the look by far … so I will keep playing with it in my own little sandbox, and perhaps someday I will learn the “bake it till you make it” flow with UE … till then, TSR I guess will have to do.
I am no fan of TAA everything. TSR seems less muddy in my tests so far, but more expensive … really, all of this has been about freedom of choice around AA + no noise shadow solutions
The other points were never the problem, but symptoms of the AA and by extension, lighting choice. Out of the box UE and even 17 days of poking at it UE … doesn’t produce acceptable results without Lumen and thus without TAA or TSR. Worth noting that going with a harder shadow sorts out the need of TAA right away and SMAA becomes viable with a few different setups but that also makes for harsh shadows could be fine for a mostly interior or artificial light type environment in our case, though no fire light, moon and sun light open areas long shadows that need to be soft … just doesn’t lend itself well especially when coupled with my limited experience with UE’s older workflows
