A special light is available to simulate the effect of sunlight. It can be used in conjunction with sky simulation to provide a dramatic background and show how the shadows cast by a structure affect the surrounding area.
In photometric lighting workflows, "Sun" lights are rendered using a more physically accurate sunlight model. For example, the color of sunlight is computed based on the time, position in the sky, date, and location specified in the drawing. Also, more sunlight properties become available with photometric lighting than in standard workflows.
The rays of the simulated sunlight are parallel and have the same intensity at any distance. The angle of the light from the sun is controlled by the geographic location you specify for your model and by the date and time of day. Whereas the rays of the sun are parallel and of a yellowish hue, the light cast from the atmosphere comes from all directions and is distinctly bluish in color. All settings for the sun except geographic location are saved per viewport, not per drawing. Geographic location is saved per drawing.
Shadows can be on or off. To improve performance, turn off shadows when you don’t need them.
The simulated "Sky" background is only available for photometric lighting workflows.
Additional sky illumination adds extra light to the scene, simulating the effect of light scattered by the atmosphere throughout the scene. This additional light is only visible in rendered output when final gather is enabled.