# Which UVs are better for light maps?

**URL:** <https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010>\
**Category:** Asset Creation\
**Tags:** static-lights, unreal-engine, Lightmap, Lighting, question\
**Created:** [February 28, 2024, 8:44pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010 "2024-02-28T20:44:03Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![VertexMachine](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/vertexmachine/32/1194540_2.png) [@VertexMachine](https://forums.unrealengine.com/u/VertexMachine)\
**Post date:** [February 28, 2024, 8:44pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010/1 "2024-02-28T20:44:03Z")

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![430221889_3514495805468247_5476785668968520001_n](https://d3kjluh73b9h9o.cloudfront.net/original/4X/1/9/2/192b7c92ff7fa03d261b4d413b9b92fd42b64ab2.jpeg)

A or B? Do I sacriface texel density or continuity?

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**Author:** ![Nawrot](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/nawrot/32/618260_2.png) [@Nawrot](https://forums.unrealengine.com/u/Nawrot)\
**Post date:** [February 28, 2024, 9:20pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010/2 "2024-02-28T21:20:53Z")

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I would pick A. Just make sure that unused space betwen uv islands is at least 4 pixels (of lightmap texture).

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**Author:** ![VertexMachine](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/vertexmachine/32/1194540_2.png) [@VertexMachine](https://forums.unrealengine.com/u/VertexMachine)\
**Post date:** [February 28, 2024, 9:51pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010/3 "2024-02-28T21:51:09Z")

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I don’t know why I didn’t test it before asking 😅 (maybe because it’s 11pm and I’m still working on this…)

But I did test it, and threw in 3rd options (generating lightmap UVs by UE)

 ![lightmaps](https://d3kjluh73b9h9o.cloudfront.net/original/4X/7/a/3/7a36545ead690f16e3282c6af7016c29eea07d7d.jpeg)

Seems that actually wasting UV space might not be that bad idea here as there is quite visible seam in shadow for A…

(that’s all default lightmass setting with 32 lightmap resolutiion for all of those objects)

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<div class="post-metadata">

**Author:** ![VertexMachine](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/vertexmachine/32/1194540_2.png) [@VertexMachine](https://forums.unrealengine.com/u/VertexMachine)\
**Post date:** [February 28, 2024, 10:11pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010/4 "2024-02-28T22:11:32Z")

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![lightmaps](https://d3kjluh73b9h9o.cloudfront.net/original/4X/9/8/6/9869f51cbacf91ba172a69714d4b15ad80b6ab01.jpeg)

Added one more variant for testing (same as ‘wasted uv space’, B in first post, but with UV islands scalled non-uniformly, so UV space isn’t wasted, but then it’s impossible to have ‘all green’ on lightmap density visualisation 😅)

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**Author:** ![system](https://d3kjluh73b9h9o.cloudfront.net/original/4X/7/1/3/713c9d3f58553f0de89543d76a8a3a2779dc9fa4.png) [@system](https://forums.unrealengine.com/u/system)\
**Post date:** [March 29, 2024, 10:12pm UTC](https://forums.unrealengine.com/t/which-uvs-are-better-for-light-maps/1719010/5 "2024-03-29T22:12:32Z")

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