Lighting Channels not supported with Raytracing?

Development Rendering
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1

Hi,

Lighting channels don’t seem to be working as expected when enabling raytracing.
Objects assigned to different lighting channels will still cast shadows on objects from different channels.

If this is the case, can we expect a fix anytime soon?

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Also I am aware that there is the option to turn off raytraced shadows for individual objects entirely, but that’s not what I am looking for.

Thank you!

2

Light channels with ray-tracing don’t seem to be currently supported, no.

However, NVIDIA has a fork of the UE4 editor that supports this feature (along with other ray-tracing improvements) called RTX-dev. It is currently unknown if the UE4 developers intend to integrate these changes into the stock editor.

The RTX-dev link is available here (you must have your Epic Games and GitHub account linked to access it, as it is a private repo), and the NVIDIA documentation is available here.

Hope this helps!

3

Thank you for your reply. I have tried the latest branch (rtx-dlss-4.25.3) but the issue with Lighting Channels still persists. Raytracing Shadows are cast on objects no matter the Lighting Channel they’re assigned to. Are you sure this feature is working for you?

4

Hi,did you fix that ?

5

No. Lighting Channels are currently not supported with Ray Tracing Shadows. Virtual Shadow Maps in UE5 do support Lighting Channels, but unfortunately Lumen global illumination does not.

6

Thanks for your reply ，and did you using NvRTX too ？

7

I haven’t used it for over a year so I’m not sure if it does support it now.

8

Thanks for your reply