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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:

In 3ds Max Design 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.