Indirect Illumination inconsistent between Edit and Play

Essentially whenever I Play the scene, the indirect lighting appears to disable/reduce significantly compared to Edit mode.



General scene composition:

  • Lumen
  • Directional light, exp height fog, sky atmo+vol clouds (though camera is far above them). Volumetrics enabled

I’ve tried adjusting just about every setting around the directional light, height fog, shadows, volumetrics/contribution. The only thing I can discern is if in Edit mode, I can achieve the reduced bounce/indirect lighting I see in Play be dropping the "Indirect Lighting Intensity from 1.0 to 0.0. But if I play, the value at 1.0 in Play looks like 0.0 in Edit. And If I try and increase the value in Play I just get stronger lighting impact but not so much with bounces.

PLAY + BOOSTED "Indirect Lighting Intensity"

The boosted intensity looks wrong because of that brigher field near the bottom of the shadow in the bottom left.

Are you sure the difference between play/edit isn’t just exposure settings / eye adaptation?

I’ve confirmed the following:

  • Issue still persists with auto exposure set with constant 1.0 min/max
  • Created a new world with the typical dir light+sky atmo+clouds and only the above foreground geometry and was also able to reproduce
  • Also tried several variations of the above geometry - separating walls/ceiling/floor into different meshes, removing window materials so they’re only holes, all produced same results.

One additional thing I’ve noticed. I actually got the Edit viewer to look the same as the darkened Play visual. It looks like this has something to do with maybe a light baking bug. I have only dynamic lumen enabled, all baking disabled/force no precompute enabled. In Edit mode if I make a change to the static geometry (toggle mesh distance field, any build param) it reverts to the darker look. But then if I click Build > All Levels it updates to the first visual that looks correct. I then also see the following in Lighting StaticMesh Info

Could there be something weird happening around the configuration state for lighting? I would think baking wouldn’t alter the image at all with Lumen/full dynamic?