Lumen, Artifacts in shadows with many movable lights

Development Rendering
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Hi. I’m on UE5.3. Using Lumen for GI, reflections. Virtual shadow maps.
I have quite a few spotlights and rect lights in close proximity to each other. When I turn most of them on, I’m starting to get strange square form artifacts, it looks like in some squares the shadow is dissapearing.
Some of the spotlights use IES profiles. I’m using the lowest attenuation possible.
I’m on RTX 4090 btw.
Here’s a video.


What could cause this? Is it some kind of shadow texture limitation exceeding?
Thanks!

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Its possible you need to increase the poolsize. Try increasing r.Shadow.Virtual.MaxPhysicalPages

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Thanks Shaun, unfotunatelly it didn’t fix the issue, but I was thinking the same, that some kind of poolsize should fix it. Will try to play with more of these console commands

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If you have a lot of local lights, you may be hitting the maximum lights per pixel threshold of VSM one-pass-projection. Try increasing r.Shadow.Virtual.OnePassProjection.MaxLightsPerPixel to a higher number

More info here: Virtual Shadow Maps in Unreal Engine

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I think this is it! Will test it out more later, but changing the values does affects those shadows.
Thanks wouterdek-dev