Ambiance occlusion confusion!

[Tore]

I am slightly confused.

I am trying to get to grips with ambiance lighting and occlusion in A:M rendering.

The problem isn’t abscense of options but the opposite: there is so many different places ambience parameters can be set, and it is not clear (to me anyhow) which of the similar labeled functions does what and what cancels each other out.

Below is a collection of the possible settings I have found

 

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Camera:

Global Ambiance (%)

 

Camera/Render Options:

Ambiance Occlusion (On/Off)

Occlusion Sampling (%)

Transparent AO (On/Off)

 

Camera/Render Options:

Plugin Shaders (On/Off)

Ambiance Render Shader (shader)

Ambiance Color (Color)

 

Choreographies/Choreographie1:

Global Ambiance Type (Color)

Ambiance Color

Ambiance Intensity (%)

Ambiance Occlusion (%)

 

Material:

Ambiance color (color)

Ambiance Intensity (%)

Ambiance Blend (%)

Ambiance Render Shader (shader)

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Is there anybody that can bring enlightenment to this?

[robcat2075]

Is there anybody that can bring enlightenment to this?

 

Basically, anything that artificially brightens the surface will negate the darkening effect of shadows and true Ambiance Occlusion

 

In A:M Materials and Surface Properties and Plugin Shaders, "Ambience" generally refers to things that artificially brighten the surface with a color and therefore don't show shadowing effects or AO as much as they might. other wise. If you modeled a Flourescent light tube that was suposed to look ON you would set it's surface ambiance to 100% so any shadow cast on it would not be visible. This does not make the tube surface emit any light of its own but it does stop it from shading like a regular unlit surface.

 

The "ambiance" term is confusing but it came into use for this sort of artificial lightening long before "real" ambiance occlusion in renders was possible.

 

 

 

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Camera:

Global Ambiance (%) artificially brightens all surfaces

 

Camera/Render Options:

Ambiance Occlusion (On/Off) you need this ON for AO effects

Occlusion Sampling (%) higher % means less grain in AO shadows

Transparent AO (On/Off) ON will prevent transparent objects from casting occlusion shadows

 

 

 

These are artificial brighteners:

 

Camera/Render Options:

Plugin Shaders (On/Off)

Ambiance Render Shader (shader)

Ambiance Color (Color)

 

 

 

These are artificial brighteners:

 

Material:

Ambiance color (color)

Ambiance Intensity (%)

Ambiance Blend (%)

Ambiance Render Shader (shader)

 

 

 

These are part of the true ambiance occlusion effect:

 

Choreographies/Choreographie1:

Global Ambiance Type (Color)

Ambiance Color The color of the all-around environmental light that is shined on all objects

Ambiance Intensity (%) strength of that all-around environmental light

Ambiance Occlusion (%) strength of the occlusion shadowing. Higher is darker.

 

 

 

I'll note that Yves Poissant, who wrote A:M ambiance occlusion effect, regards AO as a lighting effect rather than a shadowing effect (as I have characterized it above) and I'm sure that as far as the software works internally, he is correct in describing it that way.

 

I'll also note that for almost all fo these properties, if you have v17 or later, you can on most of the properties and choose "display help" to get the tech ref description of the property's meaning.

[Tore]

Thanks a lot, Robert! That made things much clearer! Hadn't thought of the difference betwen the two types of ambience. :-)