sky
This is an Expression representation of "sky-atmosphere-sun".
Position of the sun center a azimuthal angle, p polar angle. The azimuthal angle indicates the position of the sun relative to 0 degree north, where degrees proceed clockwise. The polar angle indicates the height of the sun, where 0 degree is directly above, at zenith, and 90 degree at the horizon. When this property is ommitted, the sun center is directly inherited from the light position.