vray showVFB - BigRoy/mayaVrayCommandDocs GitHub Wiki
The mc.vray("showVFB")
command shows the V-ray frame buffer.
Examples
import maya.cmds as mc
mc.vray("showVFB")
MEL example: Notice that the showVFB is not a flag but an argument and doesn't need a hyphen in front.
vray showVFB;