Description

Lumen Reflections can leave black spots in chrome materials with strong normals.

Also tested on UE 5.5, CL: 41545209 and UE 5.6, CL: 45232827

Steps to Reproduce

1. Download the attached test project and open.
2. Observe the mesh "Floor" with the conical normal map.
3. Observe the large black holes in the reflections.
4. Using "r.Lumen.Reflections.Visualize 1", observe the traces from these areas are often hitting the pixel the trace started at.
5. Observe the stretching or pouring effect as the screen traces fill in black areas with very close pixels.
6. Disable Lumen Reflections screen traces. "r.Lumen.Reflections.ScreenTraces 0"
7. Observe that, particularly on the far side of features, traces are going in unexpected directions.
8. Re-enable Lumen Reflections screen traces
9. Observe the mesh "FloorNoise" from a grazing angle
10. Observe the same artifacts, but smaller, and how they become dominant at a distance

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-350323 in the post.

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Unresolved
ComponentUE - Graphics Features - Lumen
Affects Versions5.55.65.7
CreatedOct 23, 2025
UpdatedOct 24, 2025
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