Shadow/light falloff for vray ?

Hello,

it seems that the shadow/light falloff doesn’t work with vray. Is there an alternative, or trick to achieve the same result ?

what i want to achieve is reflection of glass depending of the amount of sunlight it receives.

Thanks

It’s not perfect since it’s not light reactive as such but if you use towards / away and choose object as the falloff direction, you’ll be able to pick your sun to drive the effect.