Static mesh turning black after light build

Development Rendering
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1

Hi,
I have problems with a static mesh tree object going black, I’ve tried many of the suggestions from other people having this problem but none have worked, this is with static directional light, static skylight and a static object. The lightmap is placed in UV channel 1 (as it should be ?) and a normal UV in channel 0.

this is what I have done so far :

  • increasing lightmap resolution.
  • trying both auto-lightmaps and custom ones I made in maya .
  • changing normals in maya .
  • computing normals in ue4 .
  • changing lightmap index to different values.
  • Changed projects and maps .
  • tried exporting from maya as obj and fbx formats.

Some things I noticed:

  • turning up indirect lighting on directional light I could very faintly see the texture on the object but extremely dark.
  • I could see the ‘faint texture’ better at certain angles
  • if I moved the object I could see the texture very well and it looked good but it goes black upon building the lights.
  • if I zoomed right ontop of the object in the editor the texture slowly lights up (I’m assuming the editor auto-exposure)

All this leads me to believe its a light-map problem?
so I tried adjusting the light map UV’s by taking original UV’s(which were overlapping on purpose (image1)) and making them fit 1,1 uv range with no overlaps(image2) still didn’t work .

The material is just a two sided foliage material that I apply in the engine, so I don’t believe this is the problem.

I’m probably missing something obvious in the workflow, would it be possible for someone to take a look at the object and try and import it to UE4 ? Dropbox - treemodel.fbx - Simplify your life

Many Thanks

edit: the images below look fine because they are using dynamic lighting in the preview window. once I build them they go black.

image1 :

220181-refimage2.jpg
220181-refimage2.jpg1455×998 293 KB

image 2:

220182-refimage3.jpg
220182-refimage3.jpg1461×1037 603 KB

2

Do you have error messages on build? It happens on my side (black mesh) with errors or warnings about material uv or/and when lights are overlapped.
And bad mesh can be not this black one.

3

Hi!

I’m not sure if you could do this… this lightmap… :S I think I’ve read it somewhere that 1 or 1> pixel uv islands won’t get ANY lightmap information! So with this lightmap you should have a really big resolution to have proper padding between the islands + have enough pixels/island to get light information…

Have you tried a 2 sided foliage material already?

I would try to use (distance field) ambient occlusion to light it up nicely…

Good luck!!

4

You either have to make a new Lightmap UV with a 3d modeling tool, or you can set your object to moveable that way it should not use any lightmap information but will be worse for your performance.

5

Open it in the mesh editor, and change the Light Map Resolution to 512 and the Light Map Coordinate Index to 1. This worked for me: https://learnunrealengine.com/fix-mesh-turning-black-issue-ue4-geometry-brush-converted-static-mesh-turns-black-building-lighting/

6

Thanks for this, looks like Light Map Coordinate Index defaults to 0 when creating a static mesh from a brush.