Ambient OcclusionBasic Cache
Ambient Occlusion (AO) determines the degree to which each visible surface point is exposed and darkens it accordingly. Imagine a scene without a floor that is evenly lit by the sky surrounding it. For each visible area, AO will determine the degree to which it sees the sky (more precisely: the degree to which each visible point within a hemisphere (with adjustable radius) has an unobstructed view of the sky).
Corner areas, holes, ridges, etc. (or objects lying close to one another) will see less sky and will be darker by default:
AO is conveniently used as a simplified Global Illumination method to quickly create shadowed areas at corresponding locations.
AO can be defined at 2 locations within Cinema 4D: