Lumen indoor scene goes completely dark if lights are off-screen

Development Rendering
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I’m learning Unreal (using ver. 5.1.1) and I’m having trouble with my lighting. I have a room with a bunch of torches on one wall, and no torches on the other wall. The wall without torches is close enough to the other wall that it is still receiving plenty of light. However, if I look at that wall such that all the torches are out of frame, the scene quickly fades to complete darkness. The same thing happens with or without hardware raytracing enabled. It’s really disorienting to be exploring a level (or even editing it in Lit mode) and suddenly have everything go black because you were facing the wrong way. How can I fix this so that lights don’t blink out of existence as soon as your back is turned on them?

EDIT: I’ve recorded a video of the issue here:

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That looks like you’ve only got screen space GI

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Or is it set to Lumen?

Are you on a mac, per chance…?

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This is what my rendering settings looks like:

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image860×784 21.7 KB

I’m on Windows 11.

EDIT: One more thing I’ve noticed is that this doesn’t happen if I look directly at the floor, for instance. Even though all the light sources are offscreen, I can still see the ground. But if I look straight ahead and there’s no light sources immediately on screen, it blacks out.

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Very strange, it’s behaving like screen space only. Have you tried turning off ray tracing? I’m just guessing now, but I have seen that help some people…

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Check the Lumen debug views under lit. Make sure all your meshes have mesh distance fields enabled.

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The problem here looks like exposure.

Create a PostProccessVolume and go into Exposure->MeteringMode->Manual
Then in the option under (Exposure Compensation) tweak it to your liking! :slight_smile:

3 Likes
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Ahhh, finally, that did it. Thanks, I’d been trying to figure this out on my own for ages.

1 Like
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there is a lumen setting in Post Process → Lumen global ilumination-> Advanced → Skylight Leaking that can be tweaked to compensate dark areas for anyone that is using diectional light and exposure isn’t cutting it