use Irradiance map in Vray Material options

Wondering if someone can help me understand this setting…for example, I am using Vray lights with STORE in IR MAP off, so shadows are calc by lights. I am using IR/QMC for GI solution. Can someone tell me what effect having this on or off will have (if any) in a Vray material if I am not storing shadows in the IR map?

thanks!

well..one thing i discovered which may partially answer my question..

The reason i ask it that i have water drops on a slow spinning bottle (yes, the same one…) and while I learned that STORE in IR MAP set to OFF greatly reduced the amount of flicker in my animation. there was still some small flicker around the drops, which i thought was strange since (a) the shadows were being raytraced each frames and (b) i set the max properties of the drops to not cast shadows to speed up the render.

When I came across the use irr map in the vray material for the drops, i unchecked it but it looked the same. but when i unchecked it for BOTH the drops and the bottle material, the drops were gone. I guess now, even though I have IR map set to first bounce, vary is essentially not using it since i checked it OFF in materials? is that correct? I thought the flicker might have been from intersecting faces (the drops penetrate the bottle) and it was hopeless, but alas there is 0 flicker…

am i right about IR map not being used at all now??

thanks