save SSS2 to file

can we save SSS2 prepass to file ?
how to avoid flicker in animation and how to region render ?

a.

Region render:

Bring up vray frame buffer. Click on the top right icon (region render). Drag your mouse from one corner to the other to define the region.

you miss the question
I like to know how to region render and keep coherent borders with sss2

You cannot do that at the moment. It is scheduled for future builds though.

Best regards,
Vlado