Emissive in niagara produce wrong position light

Hi everyone,

Is there a way to prevent such bad lighting with emissive material in a Niagara particle?
The back of the corridor should not be enlight.

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With UE5 emissive now lights the environment by default.

You can stop it from happening with a hack in the material

Actually, I have no issue with the fact that the material lights the environment.
But I do not understand why the light is on the background while the closest wall is unaffected by the material.
I guess it is due to some screen space calculation but I do not get it.

I’m going to check your link, it can help me ^^

I made a short video to better explain my issue:

Do you have global illumination set to ‘screen space’ or Lumen ( project settings )?

Yes we are using Lumen in UE5.2.
But I guess Lumen is not ready to deal with transparent and emissive material?

I manage to deal with it by preventing the material to participate to the Lumen scene.

I also know that the command r.Lumen.ScreenProbeGather.ScreenTraces = 0 make the light trace disapear, but it also reduce the indirect lighting quality.

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This is an issue with Lumen when using TSR, I noted it here and here:

A fix is coming (as I understand it) but in the meantime you can use TAA.

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I just saw your answer, and thank you it was exactly this issue we faced.
I keep that as an answer.

Have a good day