Lumen reflections are now compatible with baked lighting (thank you), but number of bounces doesn’t work unless you enable Lumen GI.
So, number of bounces of Lumen reflections are not compatible with baked lighting.
It’s working fine for me too. Maybe it’s your material. Can you show it? Have you tried with a very basic translucent material, to compare?
No it’s not but you can see the effect in motion. It’s similar if not driven by the same limitations of a ray + accumulated math.
If I enable ray traced shadows for the directional light, it stops working.
Oh, I think that’s a different scenario. But you can uncheck Cast ray traced shadows inside the material params.
Unfortunately, that’s not a solution for us because we use the pathtracer too. So far, it was working with the above lumen command perfectly…
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Hello,
Ray Reconstruction demo showcase here with lumen : https://www.youtube.com/watch?v=GOhK4V9lGtU
Pretty impressive 
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Weeeelllllll… Cyberpunk sent out it´s update for downloading, and while it seems to be activated on the 26. (no clue, have not yet looked for Phantom Liberty stuff), the options for DLSS 3.5 are already there and so is Ray Reconstruction.
Which… is greyed out with normal settings on an RTX 2070 o.O
Did i manage to get it activated? Yes. Was i happy about the result? Nope 
I kinda feel scammed 
While they spoke the truth, you CAN activate Ray Reconstruction on any RTX card, and just as suspected, it is indeed independend from Frame Generation. What they didn´t mention in the trailer is, that it is tied to PATH tracing, not just the ordinary Ray tracing.
So in order to get Ray Reconstruction, i need to activate Path tracing, which is possible, but comes with a big fat warning, that its so performance hungry, that it should only be activated on an 3090 or higher.
THEN i was indeed able to use Ray Reconstruction, with a loss of 25-30 FPS…
Thanks a lot, i guess 
Just getting 29 FPS thanks to Path Tracing.
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Thanks for the reply!
I understand that lumen is mainly optimized for game environments. However it would be nice to get a quality switch that aims for high quality production where realtime performance just isn’t important.
At least in the movie render queue I think its a shame that lumen quality doesnt really scale with the amount of samples you give it. Especially the noise and flickering issues.
We are currently working on a big office space with a ton of different materials and extremely difficult lighting scenarios and we are constantly tweaking console commands while also being in contact with udn support. But one thing will often break another and its hard for a small studio thats mostly artists to figure out something complex like lumen.
It would also really help everyone working in archviz or other similar areas to get back (usable) raytraced shadows since Virtual Shadow maps are just not reaching the same level of quality and do not match the pathtracer at all. The only thing stopping us from using raytraced shadows is the fact that there is no SSS.
Bonus question: where do see lumen in comparison to realtime pathtracing like in cyberpunk especially with the fantastic results with the DLSS 3.5 integration? And can we use ray reconstruction with the build in pathtracer?
Thanks!
Is there a recommended workaround for this since it really makes translucent objects look fake?
You need to use NvRTX Caustics branch :https://github.com/NvRTX/UnrealEngine/tree/NvRTX_Caustics-5.2
It has the so far best translucency solution, and here is the just released live stream:Level Up with NVIDIA
Tried ‘r.Lumen.Reflections.ScreenSpaceReconstruction.TonemapStrength 1’
Worked great in some rough meshes but overall scene look poor. For archviz video it really helped me. I had to render twice the scene. One with default value of 0 and second one with value 1 and compose in post production. Its nice to have this workaround at least but it would be great to have some per object or per material solution that doesn´t affect entire scene. I dont know how difficult that would be to implement or if it´s possible at all but it´s a must for a lot of users. That being said, for architects like me, Lumen is a miracle using it in design early states and not only with finished products baking lights and unwrapping as we had to do in UE4. I´ve been working with Lumen since EA and the software its getting better an better. I understand the frustration that some users who need it for real time or games development are feeling, but In my opinion it´s fair to say that Epic are doing a great job even thought it is not fitting the needs of all users in its current state.
As some users said before it would be great to have a high quality switch for video in movie render queue. If we could have better mirror reflections and a workaround for noise in rough reflectionsm there will be no need for path tracer in 90% of scenes. It hard to deal with people like me who need quality and doesn´t care about performance and people who need performance for real time, I Know. Thanks for your work and for taking the time to answer forum users.
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For sure there are a bunch of things we could do. The current Lumen Reflections is designed around performance limitations of consoles, yet today’s PC GPU’s are massively faster and can afford much more work. We’re not scaling up past consoles, and we haven’t had time to work on that yet.
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I’ve seen the videos, they look amazing and it’s something we need to look into.
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Not at the moment. We’ve talked about it a lot, but there are some complications:
- Requires extra Surface Cache atlases to store ShadingModelId, Opacity, SubsurfaceColor. Lumen is already using too much VRAM, and the Surface Cache atlases don’t resize based on your use (hardcoded 4k^2), so we’d have to optimize elsewhere before we could do that.
- Trees (which the backface lighting would help) suffer from a bunch of other Surface Cache problems like missing coverage, so backface lighting is not the hardest thing that needs to be solved here.
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This looks like Ray Traced Shadows to me, not Lumen. You’re showing the lit viewport and not Lumen Scene, so the shadowing here is coming from Ray Traced Shadows, which it looks like aren’t skipping translucency properly. I don’t see how that could have been affected by the Lumen console variable. It’s something we need to fix for sure, I will do a test to reproduce and report it to someone who owns Ray Traced Shadows.
Lumen is so widely used now that we spend a lot of our time on internal and external support, rather than making forward progress. Every season of Fortnite brings new challenges (visual artifacts, performance regressions), then there are the many UEFN projects exposing Lumen artifacts, Special Projects teams within Epic having Lumen problems, the list goes on and on. Probably not what you wanted to hear, but…
Glossy reflection denoising is near the top of our team’s priority list, but it’s just hard to work on with all of our other requirements.
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Thanks, should be easy to fix.
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they look amazing and it’s something we need to look into.
For the love of God DO NOT. It does NOT look amazing in motion. Which tends to be in games?
It’s so blurry and smears in motion. We already have to deal with Lumen being temporally dependent
There is no logical sense to try to make blurry crap the standard for games. Epic games already did that with TAAU.
If you don’t think Temporal AA methods are bad go to r/f**taa.
You find most comparisons showing TAAU ruining motion/gameplay.
The biggest reason RR makes reflections better looking is because it more aggressively smears past frames on reflections. Which results in ruining everything else in motion such as NPCs and soon we’ll see third person smear like crazy.
We need common sense algorithms for games, not cinematics. Playing a path traced game at 720p makes no logical sense. We need actual performant visuals that actually play well with fast gameplay.
Stop falling for this cinematic crap.
Yes, we’re not scaling up as well as we should be able to. We do have higher quality settings that Lumen uses in MRQ (Cinematic scalability), but it still relies on screen traces / surface cache / radiance cache (which have their artifacts) and Lumen Reflections doesn’t scale up at all. Then there are the aliasing artifacts on small details that Lumen screen traces cause with AAMethod=None. And some things like Hit Lighting / multiple reflection bounces don’t get enabled automatically.
Thanks for your feedback, it’s on our minds.
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