How to Use Shadows in Google SketchUp 8
The basic thing to understand about shadows in Google SketchUp is that, just like in real life, they’re controlled by changing the position of the sun. Because the sun moves exactly the same way every year, you just pick a date and time, and SketchUp automatically displays the correct shadows by figuring out where the sun should be.
You do all these simple maneuvers in the Shadow Settings dialog box.
Turning on the sun
Shadows aren’t turned on by default, so the first thing you need to know about applying shadows is how to turn them on. Follow these simple steps:
Choose Window, Shadows to display the Shadow Settings dialog box.
In the upper-left corner of the dialog box, click the Show/Hide Shadows button.
Clicking it turns on the sun in SketchUp, casting shadows throughout your model and, generally speaking, making everything much more exciting.
Setting a shadow’s time and date
The Shadow Settings dialog box has time and date controls, which you use to change the position of the SketchUp sun. The time and date you choose, in turn, controls the appearance of shadows in your model:
Setting the time: Move the Time slider back and forth, or type a time into the little box on the right.
Setting the date: Just like the time of day, you set the day of the year by moving the Date slider back and forth, or by typing in a date in the little box on the right.
To toggle open or closed the extra shadow controls, click the triangular Expand button in the upper-right corner of the Shadow Settings dialog box.
Choosing where shadows display
The Display check boxes in the Shadow Settings dialog box enable you to control where shadows are cast. Depending on your model, you may want to toggle these on or off.
On Faces: Deselecting the On Faces check box means that shadows aren’t cast on faces in your model. This is on by default, and should probably be left on, unless you want to cast shadows only on the ground.
On Ground: Deselecting the On Ground check box causes shadows not to be cast on the ground plane.
From Edges: Selecting the From Edges check box tells SketchUp to allow edges to cast shadows. This applies to single edges that aren’t associated with faces; things like ropes, poles, and sticks are often modeled with edges like these.