VR for Sketchup render portion of image

[olen]

Hello all, I would like to render just part of a final image to both test the final output, and/or replace part of a previous image without re-rendering the whole thing. I know in some programs, you can just select a portion of the screen to render, I was wondering if this was possible in Vray for sketchup, or what the best work around would be.

 

I can't very well zoom in, because it might change the angle. Also, changing the output doesn't do anything but alter the size of the whole image.

 

I thought of putting a white plane in front of the scene with a hole cut out to render just what i can see through and take less time with the white plane, but Im not so sure how well that would work.

 

Thanks