Ambient Occlusion

Occlusion shadows are the dark areas that occur where two objects or surfaces get close to each other or otherwise block out ambient light.

A few useful points on Occlusion shadows:

• They are by nature gradients, not "lines".
• They are typically the very darkest shadows in a scene.
• Occlusion shadows are one of two methods for showing form inside the shadow family. The other method are reflected lights.

The interactive visualization below demonstrates this concept. Move the sliders to control the number of scattered ambient light rays and the distance between the sphere and the ground. Observe which areas of the sphere and ground are illuminated by ambient light (blue) and which are in ambient occlusion shadow (red).

Understanding and applying ambient occlusion significantly increases the realism and depth of both 3D renders and traditional artwork as it helps create a more natural distribution of light and shadow.