IES Sun Light (Photometric)  Create Panel > Systems > Create a
Daylight system in your scene. > Modify Panel > Daylight
Parameters Rollout > Sunlight > Choose IES Sun.  Create panel >
Lights > Photometric > IES Sun  Create menu > Lights > IES Sun
Outdoor scene illuminated by the IES Sun light  IES Sun is a
physically-based light object that simulates sunlight. When used
in conjunction with a daylight system, its values are set
automatically based on geographic location, time, and date.
Note: While you can create daylight lights manually, you should
use them in conjunction with the Daylight system to get the best
results. The Daylight system combines the two daylight
components of sun and sky in a unified interface.  Tip: If you
use the IES sun or sky with the Logarithmic Exposure Control,
check both the Daylight and Exterior option. This will provide
greater control for properly mapping the higher energy levels to
RGB colors.  Tip: In addition, it is important to set the
Physical Scale to the brightest ligh