i was doing a render with vray and i was doing this strange line in my light render testcould someone explain me why i see this strange thing.thank you
Looks like a mesh problem, are there coplanar faces there? What is it modeled in?
cool Norman Foster model!
About your problem, no idea, but it looks like a modelling problem not Vray.
yeah modelling or shadow … make sure you have smooth surface shadows on.. 
pehaps AA ?
thanks for your help it seems to be better