Description

When enabling Forward Shading in a project while using the Lumen Global Illumination system, the shadows in the viewport begin to flicker and occassionally entire meshes may appear black. The lighting also seems overblown as well.

I tested this with Forward Shading disabled and did not encounter the issue. I also tested with Forward Shading enabled, but Lumen disabled and did not encounter the issue either, so it seems to be the combination of both rendering settings.

Steps to Reproduce
  1. Open any project in UE5
  2. Navigate to Edit > Project Settings
  3. Under Engine > Rendering, tick the box next to Forward Shading
  4. Restart the engine

RESULT:

The shadows start to flicker

EXPECTED:

Forward Shading would not causing Flickering when using the Lumen GI system

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There's no existing public thread on this issue, so head over to AnswerHub just mention UE-116639 in the post.

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Unresolved
ComponentRendering - Features Teams
Affects Versions5.0-early access
Target Fix5.0
CreatedMay 26, 2021
ResolvedJun 9, 2021
UpdatedJun 16, 2021