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Weird dark spots in corners only in between sloped surfaces.

If anyone have some suggestion how to solve following problem, please help. I cannot get rid off dark spots like this (They only appear where the upper surface is sloping.):

dark spots dark spots

UV layout seem to be ok - enough spacing, but I see some analogy between uv layout elements and dark spots like below:

uv layout lightmap

Increasing Indirect lighting quality does not solve the problem. Actually I get more of them than when it was set to 4 or 6.

lightmass setting

Product Version: UE 4.19
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asked May 07 '18 at 12:47 PM in Rendering

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You don't have enough lighmap resolution to get proper results. You should have less meshes attached together because like this it's "impossible" to achieve realistic results! You just can't set high enough (the max is 4096) lightmap resolution (not to mention calculation time)! So let's say you have this max setting. Then as you can see on the attachment your wall gets 1024 res all together! ...which might be enough (I guess you had a lower res... if it was 2048 then your wall has only 512... ...)! alt text But you would have a faster build calculation with separate walls and lower lightmaps not to mention to control completely your lightmap resolution per mesh! The other thing is: snapping corners to grid/pixel + straightening edges! You'll have a lot less (or not at all!) artifacts if you won't have diagonal edges but everything is 90 degrees! You can stretch your lightmap uv island to a certain amount (I've even seen extreme cases!).

lightmap-uv.jpg (497.3 kB)
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answered May 07 '18 at 02:57 PM

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avatar image Makigirl May 07 '18 at 03:05 PM

...I might be wrong but if I see it right your walls are just planes!! Your walls should have thickness to avoid those kind of "bleeds"! For correct calculation/samples unreal needs to have inside samples/information to calculate the bounces properly! ...and if you don't have thickness you can't lower the Volumetric Lightmap Detail Cell Size enough to get inside...

avatar image krecik000 May 07 '18 at 03:44 PM

I set 2048 lightmap resolution for this object which gives me pretty high resolution for all included walls. You can see it with Lightmap Density mode (marked red everywhere). Each dark spot cover lot of lightmap pixels:

lightmap density

All objects / walls / door frames / floors etc create closed volume without any gap that light can leak through. It is working perfectly everywhere else except those sloping surfaces:

alt text

avatar image Makigirl May 07 '18 at 03:57 PM

I'm sorry, I guess we are after different quality!

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