The mentalrayUserBuffer node contains attributes that control user framebuffers. See the following sections for information on how to use framebuffers:
This option causes mental ray for Maya to interpolate sample values between two known pixel sample values. If interpolation is turned off, the last sample value in each pixel is stored, and pixels without samples get a copy of a neighboring pixel. When this option is turned on, the resulting image has a higher quality, but takes more time to process.