In the Story window, a track is a path along which you can move and edit clips along a timeline. There are six different track types, based on what the track contains:
The type of track you create depends on what asset you drop into the Action Track list from the Viewer window, Asset or Scene browser. You can also create tracks using the Insert option in the Story contextual menu. See Story contextual menu.
There can be many clips on a single track, and each track has various settings that affect the clips it contains. See Action Track controls for detailed information on track settings. Each of these tracks can also have subtracks.
An animation track appears when you drag an .fbx file containing animation or motion data from the Asset Browser to the Asset Track list.
A Character Animation track appears whenever you drag an .fbx file from the Asset browser to the Asset Track list. The .fbx file must contain motion data or keyframe animation plotted to any characterized skeleton.
Unlike other tracks, a Character Animation track also has a Track Contents menu, which lets you use props with characters.
A Camera Animation track appears when you drag a camera from the Viewer window into the Action Track list. You could also add a Camera Animation track to the Action Track list and select a custom camera from the Track Content menu.
A Constraint track appears when you drag a constraint from the Asset browser or Scene browser into the Action Track list. See Creating constraints clips.
A Command track appears when you drag one of the Command assets from the Asset browser into the Action Track list. There three types of commands. See Command clips.
A Shot track appears whenever you drag a camera from the Viewer window or Scene browser into the Shot Track list. Shot tracks are unique to the Edit Timeline. See Editing with shot clips and Edit Track list for more information.
MotionBuilder enables you to view a live scene, record source data to memory, and record source data to disk. The ability to record to disk becomes crucial when dealing with very large scene files that can easily outgrow a system's memory limit. Instead of storing the data into the memory buffer, you can store the data in real time to disk and also choose to record discrete Animation track, Character track, and Camera track clip files to disk.
