Lumen tracing reflection rays on Unlit materials

[Perfect_Human_Interface]

I’m using UE 5.7. I’m noticing in the lumen visualization that my Unlit emissive materials are showing as “pixels tracing dedicated reflection rays.” My understanding is that the “reflection rays” are only traced against materials with roughness values below a threshold (mine is the default 0.4). But these Unlit emissive materials don’t even have a roughness value.

Here you see the red areas on the floor, those are simple Unlit emissive materials. The red on the character meshes is expected.

Here is the material:

Why would it be showing up as tracing rays against these materials? Is Lumen actually doing that?

[jblackwell]

That definitely feels like a bug. You’ll want to call that in.

[Krzysztof.N]

We don’t trace reflection rays from unlit pixels it was just a visualization bug. I’m surprised that no one ever reported that before, but oh well. Just fixed it in ue5-main. Thanks!