How to Model Symmetrically in Google SketchUp 8
You can take advantage of both bilateral and radial symmetry with Google SketchUp components. To do so, assemble those components as follows, depending on what type of symmetry your object has:
Bilateral symmetry: To make a model of something that’s bilaterally symmetrical, build half, make it into a component, and flip over a copy.
Radial symmetry: Radially symmetrical objects can be (conceptually, anyway) cut into identical wedges that all radiate from a central axis. You can use components to model things like car wheels and turrets by building a single wedge and rotating a bunch of copies around a central point.
Follow these steps to get the general idea of how to build a bilaterally symmetrical model in SketchUp:
Make a simple box.
Draw a diagonal edge on the corner of your box.
Turn your box into a component.
Make a copy of your new component instance.
Choose the Move tool and then press the Ctrl key (Option on a Mac) to toggle from Move to Copy mode.
Click your component instance, move your copy beside the original, and click again to drop it.
Flip over the copy.
To do this, right-click the copy and choose Flip Along from the context menu.
Stick the two halves back together.
Using the Move tool (this time without Copy toggled on), pick up your copy from the corner and move it over, dropping it on the corresponding corner of the original.
To model something with radial symmetry, start with one wedge, make it into a component, and then rotate copies around the center. Follow these steps to get the hang of it:
Draw a polygon with as many sides as the number of segments you need for the object you’re modeling.
Draw edges from the center of your polygon to two adjacent vertices (endpoints) on the perimeter, creating a wedge.
Erase the rest of your polygon, leaving only the wedge.
Turn your wedge into a component.
Make copies of your wedge component instance with the Rotate tool.
Select your wedge’s edges and select the face, too.
Choose Tools, Rotate to select the Rotate tool.
Press the Ctrl key (Option on a Mac) to tell SketchUp you want to make a copy.
Click the pointy end of your wedge to set your center of rotation.
Click one of the opposite corners of your wedge to set your rotation start point.
Click the other corner to make a rotated copy of your wedge.
Type the number of additional wedges you want, followed by the letter x, and then press Enter.