If Motion's depth lies in lots of live parameter control, rigging combines related parameters into groups that can be controlled all at once, greatly simplifying access to that power. For instance, you might modify the display of a video in a 3D composition, adjusting the position of the camera rotating around it, changing its position in space, and altering a color balance filter on the video. With the rig, you could combine those elements and control them together, which could, for instance, greatly simplify adjusting the timing of all those elements against another video or a sound bed. It's useful enough that you really don't need FCP X to make this feature alone worth the upgrade.

To create a rig, you first select the parameters you wish to control, then assign them, one by one, to a master rig that will control all of them. The rig is composed of widgets--either a pop-up, checkbox, or slider--which provide both an interface for exported templates published to Final Cut and a means of controlling parameters within Motion itself. You can even nest widgets within other widgets. As with other Motion parameters, you can assign MIDI and audio control or behaviors like Wriggle and Random. The result is a kind of generative, modular system for producing dynamic motion effects without coding.

As with any graphical system, sometimes this makes tasks harder or less direct than with code, and sometimes it makes things a great deal more understandable. If you have experience with something like After Effects Expressions, however, you may find some of these differences refreshing and complementary, and that your background in Expression code translates well to understanding how to make the most of this feature.

Motion's plug-in architecture isn't yet as broad as After Effect's ecosystem, but this appears set to change, especially with Motion's aggressive pricing and expanded FxPlug2 SDK. Noise Industries, Genarts, and Ripple Training have shipped Motion 5 plug-ins already, and other vendors are committed to shipping updated plug-ins.