That is very curious. You might want to look at your project’s default settings then, as those are persistent irregardless of PPvolume settings. Losing all other effects is interesting, I haven’t run into your problem before myself.
Does anyone else have a problem with high quality translucent reflections (5.1) where the reflection change if you move approximately 10m close to the object?
The switch is quite noticeable and you can clearly see it when moving towards glass.
Is there a limit how far specular reflections render or something of that sort?
Lumen in 5.1 is much better than 5.0
And now lumen scene can see lot of things that it was black in 5.0
Also Lumen in 5.0 without raytracing was very bad
But in 5.1 lumen has better quality even without raytracing
Thanks @
Great work!
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Are you in software or hardware mode? It might be the global SDF trading off with the mesh SDF perchance?
Absolutely, the quality and perf are both leagues better. The bug with the unshadowed skylight and some stability issues need to be ironed out, but I feel like this plus the nanite improvements mean UE5 can serve far more use cases then it previously could. Amazing work lumen team.
I’m using hardware RT.
Is there a way to reduce this effect?
Assuming you’re using hardware RT, I’d next check if HQ translucent reflections is enabled in the PP volume or the project settings. That cutoff may be screen traces handing off to the probe, or one probe leaking through another? I’m unsure, your situation is new to me.
seems that Hi quality translucency reflection is buggy with atmospheric fog?? [UE 5.1]
Hi quality:
Low quality:
Lumen in 5.1 runs singnificantly worse than it does in 5.0.
Same project, no changes whatsoever, I didnt even fix “everything being too bright now”.
Idk, is there some hidden setting I am not aware of that just makes ~15% of my FPS vanish in some cases?
EDIT: I also noticed something with the bushes.
5.1 has some issues with foliage that 5.0 doesnt have, especially with bushes and my underwater-plants.
While Trees have become a lot “brighter”, bushes have become darker?
PS: Yes, I know that this can be fixed for 5.2 at earliest, but I didnt get to taking a “proper look” until now.
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Testing Lumen in 5.1 in VR (archviz). I know its experimental but the fact it works in VR blows my mind - game changer for an architect. My question is:
When switching streaming levels (lighting scenario) to a bright (day) level, the switch is instantly. switching to a dark streaming level, it takes lumen quite a while to catch up. Even with lighting & final gather update speeds set to 1000. Any suggestions what to try or still experimental / work in progress?
Non-VR the switch to dark is instantly so it must be something VR related?! See here
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Could the TwoSidedFoliage lighting mode enabled be contributing to your performance? I believe I read that lumen passes on TSF are more expensive than regular geo, partly because by virtue of the ‘two-sided’ part, rays can’t be pulled from instant intersections (EG hitting a wall) and moved to the other hemisphere for importance sampling. Since both sides contribute radiance, you’d essentially (could be getting this wrong), need double the ray count to get good GI on foliage.
Also, does the foliage have nanite enabled? Card capture times might be a factor.
My one thought might be something with skylight occlusion, but I’ve yet to work with lumen in VR so I wouldn’t know your problems. That being said, I’d be curious to know what the GPUdebug editor is telling you about scene change costs, because the artifacts do look like lumen propagation is happening rather slow. If you adjust the update speed in the other streaming levels, do you see their latency being affected as well?
Hi @jblackwell thanks for the suggestion. You mean using Unreal Insights or another tool?
That is an option, yes, but I actually meant simply entering ‘profileGPU’ into your command line and looking at the frame time graph. It only accounts for GPU behavior, so if this is a CPU bottleneck you can’t tell from there, but it’s good at giving you a rough frame breakdown for a given moment in time. It’s my first tool to solve perf issues before I look at more nuanced (read: time-consuming) sources for data.
Good example I had: I was getting a terrible framerate on the GPU side after loading up a scene. I had no idea what could be the cause because I was testing very well the last time I ran the scene, and profileGPU showed me that some meshes I set to nanite weren’t saved as nanite, and I was eating the cost of lumen scene update and shadowing costs for non-nanite geo. Little things like that can make a world of difference.
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@jblackwell I tested with profileGPU. I don’t think its a gpu issue. Day & night are almost the same in frame time.
- day scene: 41ms27, shadowdepth 6ms18, lumenscene 9ms42, diffInAO 12ms98, lights 1ms45, translucency 0ms98, ppv 3ms89
- night scene: 46ms06, shadowdepth 4ms24, lumenscene 9ms07, diffInAO 14ms35, lights 6ms67, translucency 1ms17, ppv 2ms55
The difference in day & night is due to the spot lights.
I did see a drawcall difference between day& night: 315 vs 1958 so I’m investigating that one. Might be something with spots that have a self-illu material in the night scene.
I expect this issue is still something in-the-works / due to lumen & VR are still experimental. If anybody has a suggestion to test though - please let me know.
Edit: added a picture showing the difference in drawcalls for the same nightscene. In the dayscene its a 100 drawcall difference (only directional + sky).
Figured it out. the problem was simply that the material was two sided…
Does Lumen support large world coordinates? In the screenshots below, taken in UE 5.1, certain artifacts in reflections (where the roughness is below about 0.4) become more and more visible as the distance of the camera from the coordinate origin increases. These artifacts look like noise due to floating point precision errors.
To my knowledge, lumen partially supports LWC. Certain passes and data structures do currently support it, but going off of the current Github notes, it’s very much in active development. It’s a matter of when, not if.
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I’m having an issue that may just be a limitation or something epic hasn’t fixed yet but I made a glass material for my scene, pretty basic, but whenever the skylight is turned on it completely washes out the entire material.
Interestingly, ‘r.RayTracing.Translucency.EmissiveAndIndirectLighting’ set to anything below 1 helps, as you can still get the direct lighting reflected in the glass, but no indirect lighting, values between 0 and 0.99 don’t seem to change the amount, it appears to be an on/off command.
Lumen currently only supports raster translucency. If you use raytraced translucency the glass will look poorly integrated into the scene as a result.
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