Occasionally, I get into conversations with people who assume that because there's a computer involved, good CG animation takes less time to make than traditional animation. In most cases, this assumption isn't true. High-quality work takes roughly the same amount of time, regardless of the tool. The time is just spent in different places. Whereas in traditional animation, a very large portion of the time is spent drawing the in-between frames, CG animation lets the computer handle that detail. However, traditional animators don't have to worry as much about optimizing for render times, tweaking and re-tweaking simulated effects, or modeling, texturing, and rigging characters.
That said, computer animation does give you the opportunity to cut corners in places and make your life as an animator much simpler. Constraints are one feature that fit this description perfectly. Literally speaking, a constraint is a limitation put on one object by another, allowing the unconstrained object to control the behavior of the constrained one.
With constraints, you can do quite a lot without doing much at all. Animation is hard work; it's worth it to be lazy whenever you can.
To see the actual constraints that you have available, go to Constraint Properties and left-click the Add Constraint button. Alternatively, you can press Shift+Ctrl+C in the 3D View. Either way, you see a menu similar to the one in Figure 10-7.