# Sams Teach Yourself Google SketchUp 8 in 10 Minutes: Going 3D

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This chapter is from the book

## Inferring Push/Pull

Suppose you wanted to draw two cubes to the same height, similar to what you can see in Figure 5.7, but are not satisfied with your first effort.

Can SketchUp help make the two cubes the same height?

Yes, it can—through inferring. Because it's so common when creating models to want one object to match another in some dimension (think of the length of table legs, for example), SketchUp allows you to set an object's length by referring to another object that already has the length you want. This process is called inferring (See Lesson 2, "Up and Running with SketchUp").

When drawing 3D objects, you can infer the length on one object to another object, making the first object's length match the second object. Here's how it works in the example of the two cubes in Figure 5.7:

1. Click the Start Using SketchUp button and click the human figure that appears in the Engineering–Feet template to select it; press the Del key to delete it.
2. Draw two rectangles in the x-y plane.
3. Click the Push/Pull tool in the toolbar.
4. Pull the rectangles into cubes of different heights, as shown in Figure 5.7.
5. With the Push/Pull tool, click the top surface of one of the cubes.
6. Move the mouse to the top surface of the other cube. A dotted blue line extends from the first surface to the surface you're inferring, as shown in Figure 5.8, and the first cube (the one you clicked first) snaps to the height of the second cube (the one you're inferring to), as you can see in the figure.
7. Click the top surface of the second cube. The height of the first cube becomes frozen to match the height of the second cube.

Inferring provides an easy way to make the length of objects match in SketchUp.