Weird stripes appear on tank's surface

I have a strange problem,

I try to render an assembly which has some tanks in it among others.

To all of the tanks appear some weird stripes on their surfaces (check attached). Of course the models themselves dont have those stripes and when i render the tanks each one alone, no stripes appear.

The issue is that i didnt have any of these problems in the past two weeks and i tried some renders of the same scene back then.

Even though i believe this is PV's problem my specs are:

Nvidia Quadro FX1700 (drivers are updated and changed back and forth to test my scene)

Solidworks 2010 SP2.1

George

SolidworksPhotoview 360