# Basic UV lightmap problem

**URL:** <https://forums.unrealengine.com/t/basic-uv-lightmap-problem/462616>\
**Category:** Rendering\
**Tags:** light, build-lighting, unreal-engine, question\
**Created:** [March 19, 2020, 11:11am UTC](https://forums.unrealengine.com/t/basic-uv-lightmap-problem/462616 "2020-03-19T11:11:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Samush](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Samush](https://forums.unrealengine.com/u/Samush)\
**Post date:** [March 19, 2020, 11:11am UTC](https://forums.unrealengine.com/t/basic-uv-lightmap-problem/462616/1 "2020-03-19T11:11:35Z")

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Hi, I’m doing a VR project about heritage and i’ve modeled all in Blender. Im exporting my .fbx as always and when I import it in UE4 it’s all OK.  
When i build lights it goes crazy and I don’t know why, I tried to do UV lightmaps on Blender (and use that maps) and I tries building lightmaps on UE4 import but both with no result.

That’s the issue, any idea? It only happens on some objetcs…

 ![298071-screenshot-10.jpg](https://d3kjluh73b9h9o.cloudfront.net/original/4X/a/0/b/a0b64e1a400556180b907bd6b8f4c83e7dd8229e.jpeg)

Note: If I use fore no precompute lighting I can see it better but not perfect at all.

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**Author:** ![presto423](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@presto423](https://forums.unrealengine.com/u/presto423)\
**Post date:** [March 20, 2020, 8:05pm UTC](https://forums.unrealengine.com/t/basic-uv-lightmap-problem/462616/2 "2020-03-20T20:05:46Z")

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What exactly is the issue in the picture? Circle / highlight it for more accurate help.

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**Author:** ![Samush](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Samush](https://forums.unrealengine.com/u/Samush)\
**Post date:** [April 29, 2020, 5:45pm UTC](https://forums.unrealengine.com/t/basic-uv-lightmap-problem/462616/3 "2020-04-29T17:45:25Z")

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Sorry I didn’t saw yuur answer, is resolved now. The issue were the black faces and the solution was increasing the lightmap size.

Thanks!