Denoise Problem behind Glass

[justix]

I had this problem before and posted in the Standalone area ( as it does occur to it too ) But received no answers and I thought I managed to solve it but Nope..

I have a nasty denoise problem with textures behind a glass, I did try almost everything from a simple plane to a thick polygon BUT even at 3000 samples the result is pretty unusable, attached 3 images were the blurred one is a denoise pass with a glass in front of the texture used for the frame but I have the same with a texture behind a shower glass, I don't know if I have to uncheck or check something BUT is just something I did not expect now as I'm in a middle of delivering some work.

Images are 1000 samples PT

Beauty pass

beauty.jpg (76.17 KiB) Viewed 2700 times

Denoise pass

blur.jpg (22.04 KiB) Viewed 2700 times

Denoise
No glass

noglass.jpg (31.44 KiB) Viewed 2700 times

[paride4331]

Hi justix,
please make sure glass and image have not coplanar surfaces.
Did you try checking alpha shadow and thill wall option in specular material?
You could also try using a fake glass.
Regards
Paride

[justix]

Hi justix,
please make sure glass and image have not coplanar surfaces.
Did you try checking alpha shadow and thill wall option in specular material?
You could also try using a fake glass.
Regards
Paride

Hi Paride, Yes I did check alpha shadow and that there is no intereferences between the 2 surfaces the glass and the diffuse one, I have no Thill Wall option as I'm on 4.05-6.30 and looking at my previous jobs I never had this issue since the Denoiser was introduced AND I usually use always 3000 samples at least. Thanks for the file but I don't run 2021 up to 2018. Something went lost in translation..

[paride4331]

Hi justix,
Regards
Paride

[justix]

Hi justix,
Regards
Paride

Right, I have to use this fake glass instead and I still think there is something wrong with the specular material? OR I totally lost touch with the Engine for some reason but have a look at this file, I used a plane with specular, the middle one is fake glass material and the right polygon is with thickness still both specular are behaving more like a metal to me that a glass?

https://www.dropbox.com/s/hmpqwl0lbs7xr ... t.zip?dl=0

[paride4331]

Hi justix,
check the unit of misure, keep in mide the number of reflections may be varied by varying the angle of incidence so you could use a falloff node to adjust it.
Regards
Paride