Hey thanks for that, and the quick response.
Unless I missed something on that page, it looked like that was the general visibility of the environment.
I have the alpha already applied and would like to just disable the HDR env from showing up in some of my refraction within a glass / specular material. In standard render there's the compositing tag with visible in reflection / refraction check box, but I'm not sure how to do it in octane...
I know it's not physically accurate, so maybe Octane struggles with this kind of thing.
Here's an example of where I'm having trouble.
Basically I'm using a c4d background there to get the white background, but would love to be able to render my glass material and omit the HDR from showing up.
I'd have other things in the scene that would get refracted but when rendering on an alpha if there's any portions that don't have a background this HDR comes through..
Thanks for the help. I'm guessing I'll probably just need to cheat it by adding more geometry and hiding it from camera or something...