Hello,
I’m having some reflection problems with Vray.
I’m using a directional light as a sun.
The material used on the ceiling has no reflection and I’ve searched the model for “wholes” that light could get through and I haven’t found any.
I’ve tried everything in my knowledge of the software and i can’t reduce the white reflection in the ceiling near the windows.
Any ideas on how to attenuate this white reflection above the windows?
Thank you
I think it’s the reflected diffuse light from the window area. It’s the natural way of light transport.So, it’s not a “reflection”, it’s a global illumination effect only. Also it could be light from the space outside. You can place a dark ground plane outside or a black invisible rectangular light as ground and block the lighting from this direction.
Thank you for your analysis and suggestion.
I’m already trying it and it seems to be working, a dark plane on the ground outside. The black rectangular invisible light it would be a better option when I have a camera where you can see the ground outside, but it won’t reduce the white “reflection”.
It could be a question of the HDRI env. You could use one with dark ground or adjust one HDRI for your need. A window opening is like a camera obscura, the outside ground send light to the ceiling and the heaven to the floor. If your env ground is to bright or you use a bright color only than it looks like a house in snow with a lot of bright light on the ceiling.
It is much better thank you, a lesson for the future.
You still notice it, but it is a bit more “natural”.
The camera obscura effect of interiors was one of my render secrets. 
@Lourenco_Barreto It is really hard to see what is going on in a scene/environment without the packed 3dm. Could you post to the forum or email me matt.newberg@chaosgroup.com the bare minimum geometry that causes this effect.
I’m sorry for a late answer. I managed to solve the problem.
Thanks a lot for your availability.