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Shadow Bleeding on flat surface

Hi My Savers

I'm encounter this problem for afew days now. really could find a solution.

As im doing cabinet with timber finish, after build the lighting, the shadow on different surface are going crazy.

so i have increased the light map resolution, it helped but still able to see the uneven shadow and i try to find the problem on the UV lightmap, have fixed the spacing between it to allowed some breathing space, it does not work too.

Please let me know if im missing anything, as im just start to learn Unreal there are lots of thing to learn.

Really appreciate.alt text

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Product Version: UE 4.11
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asked Jun 29 '16 at 08:22 PM in Using UE4

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Cleveland Zhao
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avatar image unrealnewbie23 Jan 14 '18 at 03:50 PM

did create the walls individually and put it together?

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3 answers: sort voted first

Hi Guys.

Fixed it! I'm not sure the theory behind it. Or does this problem happens to everyone but this is what i did :

  • Entering the console command r.Streaming.PoolSize (Value)

To My case i have key-in Value (2000).

I'm not too sure how is this affects the shadow bleeding problem, maybe is calculation error or something.

Maybe if some-one knows about it could help explain?

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answered Jul 01 '16 at 06:52 AM

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Cleveland Zhao
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Did you get error message on light build about overlaps? Sometimes UV's get stuck exactly on top of eachother.

Can you check your lightmap density mode to make sure your UV is 512? (sometimes people accidentally set resolution overwrite on the model inside the level, so they think it's 512 but it's actually 64).

I don't know the exact problem here, but regardless you probably want to rework those UV's anyway, that's ALOT of wasteful padding. Are these pieces moving/dynamic? if not I would just cut them togheter so that you can create a seamless UV across the entire thing, then you won't need any padding.

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answered Jun 30 '16 at 08:24 AM

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avatar image Cleveland Zhao Jun 30 '16 at 04:30 PM

Hi Sir

Thanks for your help, There is no error messages and it is dynamic pieces.

I have recheck everything according your instruction and reworked the UV again. but problem still remain.

i start to think whether it is not lightMap problem but modeling problem.

i'll keep on testing.


avatar image Cleveland Zhao Jul 01 '16 at 04:06 AM

I Think i found where the problem is.

But still, unable to Solve it. is the lighting causing the problem.

Test 1, Put the mesh individually the lightmaps are fine, looks perfect.

Test 2, Putting back to it's original position, lightmap start to going off, as the shadow start to get uneven.

Test 3. Because i have an island counter in-front of the mesh, when some object infront of it, that makes the lightmap really off...

Do you know what happen to it?

avatar image Heapcleaner Jul 01 '16 at 05:37 AM

I am not familiar with this kind of thing, but I have probably seen something similar in my previous project, and the cause was the normals of the vertices were not correct, so the solution was to fix those normals in maya.

avatar image Cleveland Zhao Jul 01 '16 at 05:52 AM

Hi Heapcleaner

I have double checked the normals, all Vertices are in the correct facing, i believe it is not the case. but still thanks for your advise.

avatar image Niberspace.com Jul 03 '16 at 07:55 AM

Since these are dynamic are you sure you even want lightmaps on these? Sure there are cases where something is only expected to move/rotate a little bit so then it's worth "lightmap as static" but other times it's safer to just use dynamic lighting for dynamic objects

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I am not sure whether you have all the meshes attached or as individual modular elements.

You can try this,

  1. in your 3d modelling tool attach the entire asset into a single mesh.

  2. Recreate the diffuse and lightmap UVs for this single mesh.

  3. Reimport in UE4.

  4. Select the asset in the scene-> Goto Details Panel -> Lighting -> Enable 'Overridden Heightmap Res' -> Set the resolution as per your preference

Also, under your 'World Settings' there is a 'Lightmass Settings' section. Play with the value that you find here. Change these values by small amounts to see the differences.

I hope this helps!

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answered Jul 01 '16 at 05:29 AM

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avatar image Cleveland Zhao Jul 01 '16 at 05:55 AM

Hi Ame

Thanks for your advice, yes all the points that you mention i've already proceed with, the model is perfectly single mesh. but still it make shadow bleeding like this: alt text

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avatar image Makigirl Jan 14 '18 at 09:00 PM


What is the lightmap resolution of the mesh on the last picture? Can you show us your new lightmap uvs? ...do you keep flat surfaces as one island?

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