Render Region mask element

Hi
Would be nice to have a render element (something like Render Region mask), which will provide the mask were white color is covering rendered regions and black color is covering the rest of the image. it will be useful in cases when multiple regions should be rerendered and composed in PS or other program with previously rendered picture. I suppose this feature will be even more useful for animation production

or, If we can combine everything in CIE, it will be less time consuming then combining in Photoshop or whatever software package.
At least if your render out as CXR’s
I have requested it here [https://forum.corona-renderer.com/ CIE request: Second Merge option - MIX function ](https://forum.corona-renderer.com/ CIE request: Second Merge option - MIX function )

Hi,

You can simply follow these steps to do what you are asking. I recorded a short tutorial for you.
Link : Dropbox - Error - Simplify your life

I hope this helps.

Regards,
Avi