Matte through Refracted object for example: Glass/ Water etc.

[Adam_Roche]

Is it possible to to matte something behind a pane of glass? Normally in C4d you can add an object buffer and it will render out the pass after the refraction, however once set up the matte in Arnold it doesn't seem to pass through. I've tried various AA settings and the opaque check box on the arnold tag on the glass. Thanks for your help in advance - Adam

[Stephen.Blair]

Refraction (aka transmission) doesn't carry through to the alpha. That's something we'll add soon.

[Shawn_Kearney1]

Thin glass can be faked if you do not require transmission or refraction. Use Utility with Metal shade node, and pipe into lambert opacity. From there you can adjust fresnel using facing ratio to drive the utility shader's "color" attribute.

Essentially you're using the specular from the utility to drive alpha.