Transparent background for studio shot with backdrop

blueman2

I want to use a simple studio type of backdrop to create shadows and light reflection onto the subject, but I want to end up with a white or transparent background when the final render is done, creating a ping file. I don't want to have to clean up and remove the backdrop thats behind the subject if possible to make it transparent. I've tried a few things like painting the backside of the backdrop with a transparent material. I've looked for various settings in vray also but no luck. Would appreciate some help.

Sketchup17
Vray Next for sketchup

Thanks

rspierenburg

]I think you are looking for V-Ray Wrapper Material see this https://docs.chaosgroup.com/display/CWVRAY3MAYA/V-Ray+Wrapper+Material

See image below.

Vray Wrapper Material

blueman2

thanks, seems like there might be something there to get me going. Found the same file for vray sketchup which is what I'm using. Will update results.