Glass with manifestation and AO pass

[3d digital]

I have a client I do a lot of interior images for; they use a lot of manifestation on their meeting room glass.

I have developed a vrayblend material to apply to the glass, the problem occurs, when I create a ambient occlusion pass, the manifestation renders black/dark grey as I have told the vraydirt material (AO)to exclude the glass model.

This is fine for stills and works great, and is fairly easy to overcome by painting it white in Photoshop. But when it comes to an animation the problem increases!

I have attached images and just wondered what other people do for manifestation and ambient occlusion passes?



PS. To reduce rendertime for the animation i made the manifestation a solid white vray material instead of having any refraction (the client didin`t notice!) but the problem still occurs!
Cheers

[deneb26]

In such situation i usually put another Plane in front of the glasspane with an opacity-map that gives the pattern (manifest). you don't need refraction at all.

greetings
Ale

[3d digital]

I have done that as well, but when you are creating an animation and cameras are on both side of the glass then the manifesation is darker on the other side. although that does solve the ambient occlusion issue.

[Zdravko]

Could you please try switch the black and white colors in the VrayDirt material. This way you will get the occlusion only.
Then you can invert the output in post, this way you won't have a problem with the alpha.