UVW size of “VRayShadows params” depends on rotation of any lights (standart or photometric), i.e. U,V & W sizes calc in the world space coordinate system instead of local. See pics for example. Picture 1: box (500x500x500) and spot with area shadow (box 1000x10x10) on the plane. Turn system (box-light) at the 45 and 90 degrees, shape of area shadow vary according to rotation of the light. Picture 2: the same effect, but with linear photometrics (instance copied) on the elevation of building
File:
http://rapidshare.com/files/33048528/lightsbug.rar.html