Arnold standin light links/groups

[BrianHanke]

I have a USD scene I brought in via standin. Everything's working great, textures, displacement, you name it. I'd like to do a bit of light linking though and I don't understand how that works. There is a light_group option for each element in the scene, but it's not clear to me how to set groups using that interface. For example, I'd like to have lights 1 and 2 hitting the face, only light 1 on the hair, and light 3 only on the back part of the hair. Any tips? Thanks!

[Stephen.Blair · Accepted solution]

A light group is an array of the lights that light the object.

The syntax looks like this:

https://answers.arnoldrenderer.com/questions/19358/light-linking-and-alembic-procedural.html

use_light_group = true
light_group = ['green_lightShape' 'ground_lightShape']

[BrianHanke]

Thanks, but I'm still not clear on how this is implemented. See attached pic. I pared down my USD scene to just the head mesh for testing. There are two lights, left and right. use_light_group bool set to True seems to do something, it turns off all lights when enabled. But I can't figure out how to point the light_group parameter to my lights. I tried every possible method of typing it in, left, leftShape, 'left', 'leftShape', middle mouse dragging the light...

[Stephen.Blair]

Hi Brian

You use the name of the Arnold light node, which by default will be /left/leftShape

and

You have to use the syntax that I showed.

[BrianHanke]

Ah, working perfectly now, thanks! I was missing the full address of the lights.