Parallax in artificial sky domes

Matt artificial sky domes are prone to parallax errors because the luminance of each element of the sky is independent of the viewing direction. Since the luminance of a real sky varies with the viewing direction, the luminance distribution of a non-uniform matt sky cannot be correct for more than one viewpoint. Unfortunately, a model building has to comprise a variety of viewpoints. Parallax errors can be eliminated if the luminance of each element of the sky dome is permitted to vary appropriately with viewing direction. Implementation, advantages and limitations of this arrangement are discussed.