OTOY Forums

I'm trying to isolate caustics for a couple glass orbs into a single light and use another light for scene lighting as well as specular highlights on the glass. It seems this is possible in the C4D plugin as I am following a SilverwingVFX video. But, in the parameter pane for one of the lights setting the Brightness values to zero seem to have no affect, except for Shadow.

I'm on MacOS, Apple Silicon, thus using the Prime version of the plugin for Houdini.

Is Ray Switching on my version not available yet? Or am I missing something?

In either case please suggest a workflow I might use. Maybe I don't need to separate the lights in my version?

Thanks,
Greg

Hey there!
If you want to use rayswitch on your light you need to use the octane universal light!
That's the only one that has it built in.

dom_otoy wrote: Wed Sep 10, 2025 1:29 pm Hey there!
If you want to use rayswitch on your light you need to use the octane universal light!
That's the only one that has it built in.

I must be missing something then. I'm using a Universal light and am changing the sliders on the parameter page in the image below. The only slider that affects the rendered image is the slider for 'Shadow', which simply makes the whole scene black if set to zero. The objects in the scene have simple Universal materials.

dom_otoy wrote: Wed Sep 10, 2025 1:29 pm Hey there!
If you want to use rayswitch on your light you need to use the octane universal light!
That's the only one that has it built in.

I tinkered a bit and found that if I set really high values for a particular ray, I can see an increase in that ray's contribution. But setting to zero doesn't make it disappear which is what I need.

Greg

Yeah, I think the issue is that most of a lights contribution goes into the "shadow" ray.
I'm not entirely sure why this is the case, but it seems this is how light rays function...
I will investigate this a bit more though.
In the meantime though you can control some of these things in the overrides section, where you can disable a light for reflections etc.

dom_otoy wrote: Fri Sep 12, 2025 5:30 pm Yeah, I think the issue is that most of a lights contribution goes into the "shadow" ray.
I'm not entirely sure why this is the case, but it seems this is how light rays function...
I will investigate this a bit more though.
In the meantime though you can control some of these things in the overrides section, where you can disable a light for reflections etc.

Thanks!
Greg