Ambient Occlusion (CineRender Effect)

This effect is available in the Detailed view of PhotoRendering Settings for the CineRender engine.
Note: As an alternative to using AO as a global effect on the whole Rendered scene, Ambient Occlusion can be applied as a shader effect to specific Surface Channels.
See Cache, below.
That’s what the Minimum Samples and Maximum Samples settings are for. They are used to affect the critical and less critical areas of your scene in different ways.
The Accuracy setting determines where and in what amount samples must be distributed in order to achieve the best possible result. In critical areas, the maximum amount of samples will be used.
Contrast: Use this setting to adjust the AO effect’s contrast. Negative values can also be entered!
Use Sky Environment: AO can work without a separate light source if the Physical or HDRI Sky is used as Illumination. If the Environment’s Sky checkbox is active, the reflected sky color will be multiplied onto the final AO image.
Note: For this to have an effect, the Ambient Occlusion texture must activated in the Environment or Luminance surface channels.
Evaluate Transparency: When this option is active, transparency will be analyzed on the basis of the Transparency or Alpha surface channels. In doing so, the degree of transparency will be taken into consideration: A semi-transparent sphere will still cause some AO in spite of this option being active.
Self Shadowing Only: When this option is active, separate objects will not see each other, they will only see themselves.