alright. just checked the shaders. i can’t really picture how it really does that ao pass. it’s screen space aligned but it raytraces it. small corners are small corners. half of the hemisphere is inside the geo. half the contribution missing. most likely the reason for the white haze.
Hi @BananableOffense ,
Sure, it will improve that resolution and all the rest of details, killing the performance. Lumen is a little bit inconceivable without TSR or DLSS, so it doesn’t look like a solution nor a workaround, IMO.
@glitchered , could you explain a little more that theory about the hemisphere inside the geo?
i dunno how exactly the hemisphere is oriented, but at narrow angles this looks like this, graphicly explained. excuse my poor painting skills. just whipped it up real quick.
It was fixed in CL 26448246 and will be included in UE 5.4.
Yes, it’s something on the todo list to make it a higher quality short range GI. Though if you want straight AO on top then likely those aren’t the changes which you will like, as it will rather reduce occlusion to be more correct and match the path tracer better.
There’s also a much more expensive HWRT version of it under r.Lumen.ScreenProbeGather.ShortRangeAO.HardwareRayTracing 1
r.Lumen.ScreenProbeGather.ShortRangeAO.MaxMultibounceAlbedo
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Hi
What are the exposure settings in PostProcess for real-world lighting in Unreal Engine 5.3?
Example: Sun 100,000 lux
Another doubt.
I see some tutorials recommending disabling eye adaptation.
Is it recommended to do this? Is the result the same as in the real world?
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Oh, I see, thank you for your explanation! Quite clear schema 
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Thank you @Krzysztof.N ,
Being closer to Path Tracing is my beloved feature, in fact! If achieved, it’s a much more desired behaviour.
It may reduce occlusion, sure, but in some zone like white walls edges (for mentioning an example), but it should increase occlusion in other areas, like under a (close to ground) sofa. The problem is when “whitenning” white painting edges is poor (far from Path tracing) and without depth, when it’s needed to add this king of faked AO. But in fact I already reduce AO intensity in my projects and my corners. So if it becomes closer to PT, that would be so great!
About those 2 cvars, I already use them for testing, but they don’t give great results:
I call Max albedo multibounce as “extra AO” (instead of “AO booster”, for example), as I feel like it adds an extra albedo layer in previous zones without AO, but it doesn’t change already existing AO zones, so no intensity change.
RT short AO looks almost the very same as “normal”. Noise micropoints are still visible. “White line” gaps are still there too:
Default Lumen Cinematic settings:
RT AO with max multibounce increased (and decreased. Tried all):
Path tracing:
Thank you!
This leaking can be reduced by replacing screen space tracing with ray tracing r.Lumen.ScreenProbeGather.ShortRangeAO.HardwareRayTracing 1 or by tweaking screen space bias under r.Lumen.ScreenProbeGather.ShortRangeAO.ScreenSpace.SlopeCompareToleranceScale.
Hi @Krzysztof.N ,
That quoted phrase was referred to the second image I posted in the post above (“RT AO with max multibounce increased”), using the r.Lumen.ScreenProbeGather.ShortRangeAO.HardwareRayTracing 1 cvar but, as you can see, it’s very very similar to the default non-RT short AO (and yes, it’s is surely enabled as it changed a very little around the sofa leg).
I also tried using the r.Lumen.ScreenProbeGather.ShortRangeAO.ScreenSpace.SlopeCompareToleranceScale before, which needs a value of ~2.0 to fully cover the gaps (and it’s a tradeoff), but this has two main issues: the AO is too much dark, but also quite noisy (so, an intensity multiplier and a denoiser or number of samples would be so great to mitigate them):
Another example of that slope compare tolerance value (All of these screenshots are in native resolution, without zooming in):
Do you know/think if there will be advancements already in 5.4 regarding the AO, or maybe in a more far future?
Thank you
I am so excited to try this out!
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No changes at the moment, but it’s something on the todo list. Can’t promise anything, as any time something of higher priority may come up or simply our ideas may not work out in practice. Can only say that we are monitoring this forum and from time to time acting on it, like in case of translucency in reflections mentioned above :).
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Any news on Single Layer Water screen traces? Not sure if you saw my previous post showing it having incorrect depth projection.
i’m (re-)cloning right now, too. this will look good in my lil mirror room? without cheats. i’ll for sure not remove that from my lightlab. also… thx @Krzysztof.N
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I know the team is exceptionally busy, but just speaking as a member of the community, I’d be really interested to hear a retrospective on how lumen came to be as a system. While the end user only sees a quite remarkable piece of tech, I’d be genuinely curious to learn more about the development path, the experiments that didn’t pan out, the breakthroughs, etc.
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I didn’t and I don’t see it here in recent posts. Please link it.
It’s not really a retrospective, but it does describe first experiments and various failed ideas:
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Does this mean like proper refractions happening through multiple objects? Like stack of glasses for example? Or water in glass etc…
hmm. slw is working as intended on my end. even abused as a wall decoration. proper fog, coverage and reflection. not sure how you generated this screentrace there. i’m using planes btw, if that matters.
i personally disable screentraces. i don’t like the artifacts it generates in general (messed up outer edges on water planes) and especially when using multibounce reflection. i mean… this is the lab. i’d have to test the benefits in a gameplay and real performance bound scenario. i have it in the city park lite test level tho and it’s doing just fine.
(devnote: the details panel can be dragged all the way over the outliner. lost access to the upper tab windows. i had to reset the ui. and saved my default while at it.)
and a offtopic question: how long does ue5-main compile first time on the average user’s computer? it’s been simmering in vs22 for a couple hours now. laptop is not sweating, but it’s for sure taking it’s time on my low end cpu.
You’ve misunderstood the issue. Reflections of objects using SLW is broken. Meaning if you look at the water surface from a reflective material like a mirror or window, it will be mis-projected.
The cylinder is using SLW in my example, not the plane.
okay. that is “broken”. i mean… it’s an edge case where you abuse the shader for something it was not designed todo. water is usually flat. ez projection. it’s not a substitue shader todo glass.
either way. it’s just another artefact of screentracing. i don’t really need or use it for reflections. idc tbh. ¯_(ツ)_/¯
It would be broken even if you use it as intended. If you look at the reflection of a normal, flat plane of water within a reflective service the reflection would be projected onto the depth of the surface below, causing major parallax issues the deeper the water becomes.
If you don’t care, don’t distract or try to diminish the issue, because other people might.