Material Behind Glass Post-Production

[carl_lorenz]

Hello, first time fourm poster, so excuse me if I'm not following protocols...

We are using Vray 5.20.06 with Sketchup 2022

We are architects with a simple question...

When we render a glass material we would like to have a post process method (photoshop) to alter the look of a material behind the glass. We've tried various render elements (such as the one's attached) but none of them are good for post processing materials that are behind glass. When the Material_Random_Color element (for example) is produced the glass fully blocks the materials behind it, which is not surprising because it is it's own material. I've also tried the Refraction element (all of them, I think) but it only gives me the RGB of the scene behind the refractive materials (such as glass).

We'd like to change the hue of an interior wall finish for each specific material for example. I've done a work around by setting up a scene with the glass off so I can access the various material masks behind the glass, but wondered if there is a better way.
The glass in the renderings attached is the Vray out of the box Glass_Window_Neutral material.

Any help would be appreciated.

Thanks
Carl

[kenancakir]

"Afect channels" option in the refraction settings should set to "all channels" as i know..

[carl_lorenz]

Thanks kenancakir

I tried the setting you suggested, it produced a material_radom_color image where the cylinder and the pink ground plane, as visible thru the glass, were merged together into one mask…So yes, your suggestion worked but kinda half way. My goal is to have masks appear via any render channel that allows me to post-process individual materials that appear behind refractive/glass materials.

Any other suggestions?

[iva_mancheva]

Hello carl_lorenz ,

For selecting objects behind the glass you can use MultiMatte Render element (make sure you assign IDs to the materials / geometries you want to apply the corrections to).
Let me know if it works for you.

Kind regards,
Iva

[wzfwzfwzf]

Need to set all channels in refraction，see the first picture。after，set channel，random color or MultiMatte objects( needs to be set Object ID),see gif。