2009

Coverage group
Clear, Partly Cloudy, Cloudy This choice determines the extent to which
light is scattered through the sky. Use the slider to set the control to one of
the named settings or anywhere in between.
Render group
NOTE These controls are unavailable when the mental ray renderer is active.
Cast Shadows Causes the sky light to cast shadows.
A great deal of processing is dedicated to the calculation of the subtle shadows
cast by
skylight on page 8129. If shadows are not important in your model, you
can disable them and save substantial amounts of processing time. However,
the results will not be as realistic.
NOTE The Cast Shadows toggle has no effect when using radiosity or the light
tracer.
NOTE IES Sky objects will not cast shadows in an ActiveShade rendering on page
6102.
Rays per Sample The number of rays used to calculate skylight falling on a
given point in the scene. For animation you should set this to a high value
to eliminate flickering. A value of around 30 should eliminate flickering.
Increasing the number of rays increases the quality of your image. However, it also
increases rendering time.
5160 | Chapter 18 Lights and Cameras