# Emissive material only visible to Lumen (invisible in game)

**URL:** <https://forums.unrealengine.com/t/emissive-material-only-visible-to-lumen-invisible-in-game/620888>\
**Category:** Rendering\
**Tags:** unreal-engine, UE5-0, Rendering, Lighting\
**Created:** [August 3, 2022, 10:14pm UTC](https://forums.unrealengine.com/t/emissive-material-only-visible-to-lumen-invisible-in-game/620888 "2022-08-03T22:14:05Z")\
**Posts on this page:** 1\
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**Author:** ![BenVlodgi](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/benvlodgi/32/1194567_2.png) [@BenVlodgi](https://forums.unrealengine.com/u/BenVlodgi)\
**Post date:** [April 19, 2023, 4:19pm UTC](https://forums.unrealengine.com/t/emissive-material-only-visible-to-lumen-invisible-in-game/620888/2 "2023-04-19T16:19:55Z")

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5.1 Added `AffectIndirectLightingWhileHidden`. [Release Notes](https://docs.unrealengine.com/5.1/en-US/unreal-engine-5.1-release-notes/).

> Added an `AffectIndirectLightingWhileHidden` property to the `Primitive Component`, which allows hidden primitives to be injected into Global Illumination (GI) and Reflections. This is useful as an extra art direction tool to create cheap invisible area lights through GI.

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