Free 3D Modeling Software - 3D Printing: Build your Own 3D Printer and Print your own 3D Objects - page 116

Figure 6.15 There's an easy way to line up objects.
You'll have times when you need objects to share a center line or an edge, and to
do this, you use the Adjust drop-down menu. First, select the objects you want to
line up. To do this, press and hold down your mouse button and draw a selection
rectangle around the objects. As you can see in Figure 6.16 , I've selected both ob-
jects—you can tell because both objects are surrounded by a dotted line.