Hello,
Here’s my problem. I have integrated a led screen on my stage, but I have a rendering problem with lumen, the reflections don’t load quickly enough and when there are strobes or fast videos the reflections are super slow (video attached).
The video signal comes from a Blackmagic capture card, I have the same problem with NDI…
Maybe Lumen isn’t made for this idk ? I’m still new to unreal
Do you have any ideas?
Video : Lumen reflections problem - YouTube
PC Config :
I9 10900X
RTX 4070
32GB RAM
Many thanks
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I don’t think you’ll get that working with Lumen. It needs a few frames to get the GI sorted out, and you’re just not giving a chance. Might be best to turn Lumen off for that sort of scene.
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Lumen Lighting Update Speed
Lumen uses a number of caches to achieve real-time performance. While local lighting changes propagate quickly, global lighting changes, like disabling the Sun, can take multiple seconds to propagate. Projects can use the Lumen Scene Lighting Update Speed and Final Gather Lighting Update Speed controls in the Post Process Volume to work around this delay at the cost of increased GPU cost.
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I might recomend figuring out a way to feed that screen buffer into the source texture of a rect light covering the bounds of the screen mesh. Analytical lights can update way, way faster than lumen, and if you have RT with soft shadows you’ll get a very similar effect to lumen reflections.
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You can disable temporal accumulation, but it won’t have enough information and would generate tons of noise, as Lumen is temporal-accumulation dependent.
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