Ambient Occlusion Transparency

[sanny]

Hi,
I have a scene where all my objects have a surface shader with the outColor connected to a mib_amb_occlusion. I need this to have an infinite white background plane and it gives a really nice illumination effect to the scene.
But i'd like some of my objects to fade out of the scene and become completely transparent. The problem is that if i change the outTransparency of the surface shader to 1 the object is still visible and if i keep raising the attrubute the object just gets brigther and brigther.

I'm sure there is an easy way to achieve this, but i just can't find it.
Any help will be appriciated.

[failure]

you don't need surface shader on objects, just on plane. For objects you can plug occlusion output into diffuse channel of say blinn shader.

[sanny]

i'm sorry but if i try to connect the mib_amb_occlusion to the shader (i decided to use a lambert for my scene) the connection editor show up. I can't connect the outValue to the diffuse channel. I can connect the outValue R, G, or B but only one at the time...

[failure]

Connect it via luminance node ( it converts rgb to single channel luminance ). But you can as well connect only one of the r, g, or just leave it unconnected for now. It really has nothing to do with infinite white plane. Joojaa just used same material for plane and object in example you got. So for start try to use surface shader w ambient occlusion for plane and regular materials for your objects. When you get a grip on it you can play with plugging the occlusion into various channels of your materials.

[sanny]

Hey,
Yes, i know it doesn't have anything to do with the plane, but it just gives that really nice effect to the illumination. It looks a bit like FG or GI but it's a lot faster to render...
Sadly, i tried to connect the mib_amb_occlusion out values to the luminance node and then connect its outValue to the diffuse but, when i render, Output window says:
API 0.0 error 301041: incorrect member "occlusion_in_alpha", "mib_amb_occlusion" does not return a struct.
even if i try to connect one of the outValues of the occlusionNode (say the red) to the diffuse i get the same message.
^^
I'd like to have both the white infinite plane and the nicely illuminated scene. And I don't get why the connection doesn't work properly.
(by the way i have Maya 6.5)
But thanks anyway for your interest.

[sanny]

Hey, i managed to get the occlusion connected to the shader !
The solution is simple but i can't understand...
instead of connecting the outValue Red of the mib_amb_occlusion to the red inputValue of the luminance and the outGreen with the inputGreen and the outBlue with the inputBlue, I just connected the outputValue with the ImputValue.
And it worked!
... I can't see the differece between the 2 connections though.

But my objects came out black..
So i tried to connect the mib_amb_occusion directly to the color of the shader and the results were great.

Anyway, thanks a lot for your interest and the great help you gave me Failure.

PS: i also found some nice staff on the maya help about occlusion... Next time i'll try to look for the solution in the help before posting a message.