VRayVFBMaxScript
This plugin gives MaxScript access to some of the properties of the V-Ray frame buffer. Currently only the rendering region is exposed, but more parameters will be added.
See included readme for installation
Disclaimer
This plugin is provided *as is* - it is not a part of the official V-Ray installation and no official support for it is provided. It is only guaranteed to work on V-Ray 1.5 SP5. For any problems or questions please use the V-Ray forum at http://www.chaosgroup.com/