The Ambient Occlusion integrator renders images by performing illumination via Ambient Occlusion (Note that scene lights are ignored during rendering).
By default, the Ambient Occlusion integrator evaluates the basic diffuse component of materials. This can be changed by disabling Use Raw Color so that a custom color can be set for all items. The number of samples used to compute the Ambient Occlusion can be set using the Sample Count attribute.
Scene objects assigned with the default material
project://default/material are rendered in pink.
Mountains with default material appear in Pink
It is possible to change the occlusion color which is black by default.
You can control the maximum radius or length of Ambient Occlusion rays using the Radius attribute. By default, Radius is set to infinite which means that the rays will stop only when a geometry is intersected along the ray path.
It is also possible to control the angle the cone used to sample the ambient occlusion using the Angle attribute. A value of 180°, samples the hemisphere aligned to the surface normal whereas a value of 0° directly launches the occlusion rays along the surface normal.
You can force the integrator to evaluate the transparency channels of materials by enabling Evaluate Transparency.