Positioning the Sun Manually

To position the sun manually:

Display the Sky & Fog palette by clicking the Sky & Fog button at the top of the Bryce window.
Click the Sky Lab button. The Sky Lab appears.
In the Sun Controls area, drag the larger highlight area in the Sun Position Controls to the position where you want the light to originate. You can position the sun, or the moon, on the horizon as you like by nudging the Sun Control until the light is visible in your scene.