Light Groups (Noob)

[Gobo]

Hello,

Is there any way to calculate the specific indirect components into a Light Group element?

Cheers,
Axel

[Dade]

Is there any way to calculate the specific indirect components into a Light Group element?

A light group always includes both Direct+Indirect: you have to render the image with only the light(s) you are interested and, at that point, you can use indirect light AOV.

[Gobo]

Then i am doing it wrong in Blender:

- Specify Light Groups in Blender View Layers
- Add lights to Groups
- The Light Groups appear as AOVs in the Compositor Render Layers
- Looking at one of them they are direct only

How can i approach it in a better way?

Thanks!

[B.Y.O.B.]

Can you show images?

[Gobo]

Original render

Lightgroup channel (Looks like direct only)

Default channel (Ha, indirect hangs around here - If i render all Lightgroups *all* indirects are mixed in here)

[Dade]

Ah, but are you using PhotonGI indirect cache ? It doesn't support light groups at the moment

[Gobo]

I see. Ok, i used Photons, so that was it. Is that planned somewhen in the future, or is it technically not possible? Kind of tricky to render scenes like the ones attached with a pure path tracer at all.

Thanks for helping, Axel

[Dade]

I see. Ok, i used Photons, so that was it. Is that planned somewhen in the future, or is it technically not possible?

It is possible, it requires some work and it is not hard to do. But it is likely to have a separate cache for each light group so it can be quite expansive from memory usage point of view. It has also a little cost even if you use a single light group.

This is why you can do multiple renderings, one for each light group, enabling only the lights in the light group, mixing the results in post-processing and get the same result (aka light groups "by hand").

[Gobo]