The basic behaviour of this shader is the same as that of the "sky" light source shader. It models the sky as a hemisphere of infinite radius positioned above the centre of the current scene. See SKY SHADER CROSS-REFERENCE for more information on this. The major difference, however, is that this shader models only that light from the sky which passes through the portal defined via the "area shader" parameter. A typical application of the "area sky" shader would be to model the light coming from the sky through a window or open door into a scene.

The "area sky" light source shader has two parameters, both of which are of type LtShader. A "sky" light source shader should be passed via the "sky shader" parameter. All of the parameters for this shader (except for "shadows" are also used for the "area sky" shader. Their meanings are the same in each case.

The opening that the light from the sky is to pass through is defined using the "area shader" parameter. The following parameters of this area shader can be set and are interpreted in the standard way by the "area sky" shader: "primitive", "min lod", "mid lod", "max lod", "noise factor", "shadows", "shadow resolution" and "shadow quality". Any other parameter settings are ignored. For further information on the meaning of these parameters see AREA LIGHT CROSS-REFERENCE.

Note that if an invalid or NULL "sky shader" is passed as argument then the area sky shader will default to standard area light behaviour. If an invalid or NULL "area shader" is given then the area sky light shader will not be able to provide useful illumination.

See here for an example in .lwc format.