Background Refraction Dulling Effect on Glass

[ali_cgi]

Hi Guys,

Im trying to use a photographic background, behind a building and a car both with a lot of glass,
Now whatever I do the refracted areas are too dark, I've switched all fog and reflection off on my glass material and made refraction white no glossiness to test with, so i should get a true colour,

Ive tried all sorts, background in env slot, vraymtlwrapper, a mixture of the two, but always a darkening effect

Any ideas, I know i can do this in post, but if i want to use real dof I'm stuck,

Is this a limitation or can it be achieved,

Any help would be fantastic.

Thanks

[Morne]

Try sticking that background into the Vray ENVIRONMENT override for REFRACTION

[ali_cgi]

no luck with the I'm afraid :/ everything in bg turns black,

Also using physical sky in go and reflection/refraction slots.

[Morbid Angel]

here is an educated guess - you are using physical sky with physical camera and background image is ignoring the exposure. Therefore the actual refracted part of the image is rendering super dark since its being underexposed.

[ali_cgi]

Hi yes this is the setup, however when background is not affected "colour mapping checkbox" the refracted image in the glass is still affected. The background is fine in normal areas were you see straight at the background.

I have tried using a camera mapped image projected onto a plane for only the refraction, with a camera wrapper on matte surface but not matte for the refraction,

Also tried just using the background,

Both of these techniques produce really dark refracted areas

Thanks

[Morbid Angel]

can you provide a scene with a simple example which clearly demonstrates the issue along with your max and vray versions so we can take a look?

[ali_cgi]

I shall send a scene on monday,
I think the problem is that that object i'm using to be scene in refraction is being affected by the lighting etc in the scene, which is why it is looking dull, but whatever I do to try and tell it not to be affected by gi etc it goes black and nothing renders, I'm on max 2016 and V-ray 3.20.03, Windows 8.1