Whenever an object moves through world space, you can view its trajectory. A trajectory is the visible path the object makes because of its movement. You can think of a trajectory as a three-dimensional function curve for the Position track of an object.

Scooter following a trajectory

Object trajectories appear with the following properties:

• The trajectory curve is drawn in blue.
• Frame increments are displayed as yellow dots on the curve.
• Position keys are displayed as white boxes surrounding the appropriate frame dot on the curve.
• Selected keys are displayed in gray.

In 3ds Max trajectories are created from animated objects. You must animate the object first in order to create the trajectory.

The Path constraint lets you picks a spline in the scene to use as a motion path for an object. The spline becomes the object's explicit trajectory.