The angle, in radians relative to center, below which to render the ground color.
- iOS 9.0+
- macOS 10.11+
- tvOS 9.0+
- Model I/O
By default, Model I/O renders an infinite sky above and below. If you set the
ground property, Model I/O renders a solid color for all areas of the cube texture below this elevation. An elevation of
0 renders a horizon at the center elevation of the sky cube; negative values lead to a lower horizon and positive values to a higher horizon.