Dynamic Actors turn very dark on streaming levels!

Development Rendering
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1

I’ve been desperate to find an answer to this lighting bug, this has been going on for several UE4 versions and nobody seems to know why. So if anyone has some insight on this issue, please let me know!

I have quite a few sublevels that load in and out in a persistent world via level streaming volumes. When the next level loads via player streaming volume overlap, any level that’s still loaded, all of its moveable actors and blueprints actors turn dark! Some almost black! And it doesn’t matter the distance between levels, as long as it’s loaded in the persistent world. I’ve tried a new persistent level with nothing in it but the sublevels. I’ve tried package builds, same issue. I don’t know what else to do. Each level has its own baked lighting, own lightmass importance volume, and post-process volumes. Only the persistent level has a skylight and directional light which is set to moveable. The sublevels are only baked point lights and spotlights.

Here’s how the level looks before anything else is loaded.

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Here’s how the level looks after another sublevel loads in.

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And if the player were to return to this sublevel, and the previous sublevel unloads, the dark assets stay!

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I’ve only seen a few other posts with this issue and they never got an answer. If anyone has any insight, please let me know!

Here’s a youtube video of me bringing in the levels as well.

2

Could it be the sublevel PP volumes? You can’t have more than one loaded at once.

3

@clockworkOcean Thanks for the reply. I have completely removed all PP volumes for testing. I’ve removed the skylight and directional light from the persistent level. I just recently moved all of this over to a World composition setup to see if it would load differently. Nothing. I’m seriously out of options. If I begin from my main menu, although it’s a completely different persistent world, everything is already black on initial load! I’ve tried level streaming volumes and BP streaming. I even started a brand new empty level, dropped in these levels, and it’s still doing the same. What in the world am I missing?

4

The only thing I managed to narrow down is if I stream in a level with ONLY moveable lights, it won’t affect the actors. But I then set those lights to static and built them. NOW they are affecting other dynamic actors. So why would cached lighting be the culprit?

5

I don’t really know the ins and outs of it, but I think the engine has problems with more than one level loaded which was built with static lighting.

With my stuff, in the end, I gave up and used moveable directional and skylight. You can get a very similar effect with distance fields and a bit of careful tuning.