Ambient Occlusion issue

magaremoto

Hello to all,
does anyone know why some decal don't get transparent in AO mode? I've checked both the light through transparency filters but the outcome is as in the following images; some are good others don't. It's a known bug or what?

evilproducer

Am I correct in assuming the issue you're having is the circular emblem on the wall in the first image, and the graffiti in the second image is what looks correct?

What are you using for the alpha channel? An image map? Have you compared the settings in the shaders that work versus the shaders that don't to see if there are differences in how they're set up?

wetcircuit

I'm going out on a limb, but…

AO is a geometry trick, not a "lighting" trick. I believe the set you are using is Stonemason's, and the way he created the decal areas is by adding a "sheet" of geometry that floats in front of the wall - since Poser and D|S do not necessarily have Carrara's way to create a decal in a shader, or possibly he was creating a "morph" way to hide the graffiti.... What you are seeing (I believe) and the reason you are only seeing it under AO, is that the extra layer of geometry is creating a shadow because it hovers close to the wall (AO is a geometry trick…).

There have been discussions in the past about this, and I haven't tried to "fix" one myself under these conditions. You might consider using the morphs or whatever that can hide the graffiti layer, and using carrara's shader room to select the area of the wall and add the decals as a shader layer.… But maybe others have worked with these sets and have come up with other solutions...

magaremoto

thank you both
EP I have checked what you suggest and yes the same decal used for the dirty wall works fine on the wall next to the yellow pole but not on the brick building; I'm going to deepen such strange behaviour
Holly I was wrong the problem seems to be present even without AO; only with IL checked it vanishes. I hope to get out of this headache

evilproducer

Have you tried Holly's suggestion about the Morph issue?

magaremoto

evilproducer said:

Have you tried Holly's suggestion about the Morph issue?

yes EP I have tried almost everything in my ability; meanwhile, I have identified the guilty, it's an annoying bug related to the GI sky light function: below you can see 2 screenshot, with no sky light checked , with sky light intensity set to 30%. As Holly has pointed out it must be a sort of shadow casted on the wall. So I have used a curve filter in the alpha channel to enhance the contrast between opaque and transparent and here is the amazing result

EDIT: the right sequence from top is: 1-3-4-5-2