A traditional ambient occlusion effect can be accomplished by setting the occluded color to black and unoccluded color to white.
Occluded and Unoccluded
Resulting colors for occluded and unoccluded shading.
Controls the number of occlusion samples per camera hit point.
Sample distribution can be uniform or cosine.
Sample spread of rays for cosine distribution. A value of f 1 gives Lambertian distribution.
Falloff values greater than zero create a softer look. Values less than zero give a hard edge when combined with max distance.
The max distance at which objects may occlude.
Trace rays in the direction of the surface normal (outside), inverse to the normal (inside), or in both directions.
Add a directional bias to the normal vector. Values must be specified in world space.