Ground plane
The ground plane provides an infinite horizontal platform for the image that stretches to the horizon in all directions positioned at a defined elevation. The ground plane renders much faster than using a large planar surface as a base.
Enabled
Turns the ground plane on.
Ground plane disabled (left) and enabled (right).
Alpha
Applies a transparent alpha channel to the ground plane so the image can be composited with the cast shadow into another image. See: Wikipedia article: Alpha compositing.
Ground plane shows shadow, but is otherwise transparent in the image.
Elevation
Specifies the ground plane’s height above zero.
Ground plane elevation above zero.
Material
Assigns a material to the ground plane.
Ground plane with raised elevation and water material.