In kind of a pinch here and running out of luck and time. 
Is it possible to render a traditional matte shadow object in vray like you can with scanline? (i.e. not having to run out a seperate pass.) I have a floor with a matte shadow material on it with some objects sitting on it and I need to get the shadows from those objects to cast on the floor. Is there a setting I should be turning on in the vray properties for the floor object?
thanks a heap!
To get something similar, set your floor to be a matte object, set it’s alpha to -1 so it cuts out objects, turn on shadows and affect alpha and that should be you sorted.
tick the matte object box, shadow, and affect alpha, then type in -1 in the alpha contribution, and you should get a matte surface pretty much the same as matte shadow.
lol you got there before me!
Bloody brilliant! Thank you! I owe ya!! I knew I was missing something obvious 
It’s a really handy option for vfx stuff since it doesnt destroy any of your material assignments - glad you gave up that silly brazil lark 