strange swirls in rendering

[skurl]

hi guys, need some help here, i have some strange swirls appearing on one side of my building, has any ever similar troubles?

[Morne]

that looks like moire pattern. Try switching to a different filter
see here: http://www.spot3d.com/vray/help/200R...ge_sampler.htm
scroll down to example 9

or just render at higher res

[skurl]

interesting, though i see that it cant be iliminated or avoided based on the notes in vray's help pages but why is it only turning up when i do night renderings?