Lighting across meshes inconsistent, can't work out why

Seraphim3D

Hey all,

I'm currently working on a scene and I'm having trouble with the lighting. There is a directional light casting through the windows which is achieving this effect:

However, on the other side of the archway, the lighting isn't casting across the meshes in a consistent fashion:

See how those seams appear on the walls? I've been trying to determine the cause and I can't work it out.

I tried posting this on the Polycount Discord and ran through some solutions that a user suggested, but none of them worked.

I've checked the meshes, there are no problems that I can detect. The faces aren't flipped, there are no unwelded verts, etc.

The light maps are fine, there should be no cause for concern there.

I've got additional lights placed behind the wall but that didn't help either.

I also tried adjusting the reflection captures but again, no luck.

It's not caused by auto exposure or the ambient occlusion from the post processing volume. I tried disabling it and playing with the settings but nothing changed.

I've never encountered this problem before and I'm not sure if it has a name. Does anyone know what this is or how to fix it? It's been driving me crazy all day!

FULGORE

Looks like that area is lit indirectly, by the bounce lighting, so a couple more things to check:

• Lightmass settings for the Level? Static Lighting Scale, indirect lighting quality, etc. Scale set to 0.1 seems to give good results for a final bake
• Where we're seeing the seams, are those separate assets? If so, you can select and Merge the actors. This is what I do if I make a room from modular pieces but it can benefit from the merge - one of these benefits is usually cleaner baked lighting results. It looks like a common issue people often run into with building UE4 architecture with multiple separate pieces

If that doesn't sort it, I'd go through the buffer view modes and check if anything in there looks weird, e.g. somehow a face has 100% mid-grey in the AO, etc (I see this waaaay more frequently than I'd like)

frmdbl

It hardly looks like there's any lightmaps applied, just post process AO.

Try making sure that the Lightmap UVs are ok, and they are assigned to the right channel and check the Lightmap resolution viewmode.

Seraphim3D

Thanks for the responses! I've taken a look and tried your suggestions, but now I'm a bit more baffled than ever.

I've set the static lighting scale to 0.1 and tried a bake but it didn't seem to change anything. The indirect lighting quality is set to 1. The Compress Lightmaps setting is currently enabled but the engine is warning me against disabling it.

Merging the actors removed the seam, however the front face of that asset is still a darker tone than the rest of the area for reasons I can't ascertain. I've been through the buffer visualisations and whilst I haven't screenshotted them all, there's nothing standing out as to why that's happening. This is that area of the corridor:

And this is the overview for buffer visualiations:

The one that i figured would be obvious is the ambient occlusion, however it was just flat white:

However, when I tried to take a look at the Lighting Only visualisation, I found this:

It appears that the issue is lighting or lightmap related. See how the spotlights are tinted a beige tone, and that's casting on the wall and floor but nowhere else? Isn't that unusual?

This is the resulting lightmap that was generated when I merged the assets:

It doesn't seem too unusual to me. Weirdly enough, the wall on the left is the rear face of the same wall that's in the kitchen. This is how it looks from the other side.

From the front of the scene, everything is working great. It's just in that corridor where things are acting awkwardly.

Is there anything from what I've just said that might indicate what the problem is? Do you think the problem is lighting, lightmaps, lightmass settings, or something else?

Thanks for your time and I hope you have a pleasant day!