This is used to render parts of the scene selectively.
If the GameObject's layerMask AND the camera's cullingMask is zero then the game object will be invisible from this camera.
See Layers for more information.
See Also: camera component.
// Only render objects in the first layer (Default layer)
camera.cullingMask = 1 << 0;
// Only render objects in the first layer (Default layer)
camera.cullingMask = 1 << 0;