SketchUp contains a variety Shadow setting options allowing you to manipulate the use of shadows within your model.
Display shadows button
Use the Display shadows button () to toggle between displaying and not displaying shadows within your model.
Time Zone drop-down list
Select a time zone form the Time Zone drop-down list to identify your location for accurate shadows.
Use Time slider to adjust the time of day used by SketchUp to determine the location of the sun for shadow casting. The slider adjusts the time from sunrise to sunset, with 12:00 noon in the middle of the slider. Type a time into the time text field to set a precise time.
Use the Date slider to adjust the day of the year used by SketchUp to determine the location of the sun for shadow casting. The slider adjusts the date from January 1st to December 31st. Type a date into the date text field to set a precise day. You can specify the date in numerical form (11/8).
Use the Light slider to control the intensity of the light in the model. (it lightens or darkens light). This option effectively lightens and darkens illuminated surfaces.
Use the Dark slider to control the intensity of light in the model. This option (it lightens or darkens shadows). This option effectively lightens and darkens the areas under shade and shadows.
Use sun for shading check box
Click the Use sun for shading check box to use the sun to shade parts of the model while not actually casting shows.
On faces checkbox
Use the On faces checkbox to enable casting of Face shadows. This feature makes intensive use of your 3D graphics hardware and can cause performance degradation.
On Ground checkbox
Use the On ground checkbox to enable the casting of shadows on the ground plane (the red/green plane).
From edges checkbox
Use the From edges checkbox to enable the casting of shadows from edges that are not associated with a face.