Casting Real-World Shadows

With SketchUp's Shadows feature, you can make your model cast a basic shadow or see how the sun casts shadows on or around a geolocated model.

When you're casting real-world shadows, SketchUp's calculations are based on the following:

  • The model's latitude and longitude
  • The model's cardinal orientation (north, south, east or west; see Adjusting the Drawing Axes for details about how the drawing axes are aligned to the cardinal directions)
  • The selected time zone
Tip: The Shadows feature can give you only a general idea of how the sun and shadows will look at a specific location. The time is not adjusted for daylight saving time. If the model is geolocated in an area where time zone lines zigzag rather dramatically, the time zone may be off by an hour or longer.
Tip: Before you can cast real-world shadows in a model, your model must be geolocated. To geolocate your model in SketchUp Pro 2017, you can import terrain using the Add Location tool. Or to add a location manually in any version of SketchUp, select Window > Model Info, select the Geo-location option in the sidebar on the left, click Set Manual Location, and enter a latitude and longitude in the dialog box that appears. After you model is geolocated, SketchUp knows (roughly) how the sun will shine on your model.

By default, shadows are turned off, because they can use a lot of your computer's processing ability. To turn on shadows and see shadows at different times of day, follow these steps:

  1. Select View > Shadows. This enables the Shadows feature.
  2. Open the Shadows panel in the Default Tray, where you can control how the shadows appear. (Alternately, you can display the Shadows toolbar; Customizing Your Workspace explains how to show and hide toolbars.)
  3. To select the time of day, drag the Time slider along the timeline or enter a time in the Time box.
  4. To select a month and day, drag the Date slider or enter a date in the Date box.

In the following figure, you see the how the shadows change from 7:00 a.m. (top) to 3:30 p.m. (bottom).

Beyond the basic shadow settings outlined in the preceding steps list, you can customize a few more shadow attributes in the Shadow Settings dialog box:

  • The Display Shadows button in the upper left toggles the shadow display on and off.
  • The Time Zone drop-down list enables you to choose a new time zone. If your model is geolocated, this time zone should be accurate, but you can check that it's correct or change it if you like.
  • The Light slider controls the light's intensity. This option effectively lightens and darkens illuminated surfaces.
  • The Dark slider controls the shadow's intensity. With this option, you can lighten or darken areas under shade or shadows.
  • When the Use Sun for Shading checkbox is selected, SketchUp's simulated sun shades parts of your model even if shadows are toggled off.
  • The On Faces checkbox enables faces to cast shadows on other faces. This feature gobbles up your graphics card's processing power, so you might try deselecting this option if you want to display shadows but the feature is causing a performance problem.
  • When the On Ground checkbox is selected, your geometry can cast shadows on the ground plane.
  • The From Edges checkbox controls whether edges that are not associated with a face cast a shadow. By default, this option is deselected.
Check out this blog post for more information on how to control shading in your SketchUp models.
Tip: Have a transparent face that isn't casting shadows? When the material applied to a face has an opacity of less than 70%, the face stops casting shadows. If you want a transparent face to cast shadows, edit the material's Opacity setting to 70% or higher.
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