A track is a linear representation of animation occurring over time. You can think of a track as a long, straight railroad track, with the animation start time at one end, and the finish time at the other. Each animation key appears on the track at the time of its occurrence in the animation. Every item in the Track View hierarchy has a track that shows how the item changes over time.

Range track displayed in track bar below time slider

There are several types of tracks in 3ds Max:

• Animation tracks contain the actual animated values for an item. Only controller items have an animation track.

  The values in an animation track are usually displayed as keys. Some controllers don't use keys and instead display their values as a range bar or some other graphic symbol. For example, the Wave Form item displays a sound file as a two-channel sound wave.

  Animation tracks are also the only track type that can be displayed as a function curve.

• Range tracks indicate the range of time over which the animation occurs. These are available mainly in Track View in Dope Sheet mode, but also, optionally, on the track bar. To display the range on the track bar, select the keys for the range, then right-click and choose Configure Show Selection Range.

  In the Dope Sheet, range tracks indicate when items below the track are animated. A range bar in the track displays the frame range of time over which the animation occurs. You can edit the range by dragging the track or its endpoints.

• In the Motion Mixer, the linear areas that hold motion clips are called tracks. You can stack multiple tracks to use animation from all tracks at the same time.

Special tools are available for working with tracks in character studio, including the following:

• Tools are available especially for working with biped tracks. The center of mass is unique in that it has separate tracks for horizontal and vertical animation, which you can select on the Motion panel Track Selection rollout. You can copy and paste tracks on biped objects to other bipeds with the Copy/Paste rollout.
• In the Keyframing Tools rollout, you can clear all animation or just selected tracks.