Everything you animate in 3ds Max is handled by a controller. A controller is a plug-in that handles the storage and interpolation of all animated values.
The default controllers for transform animation are:
Although 3ds Max has many different types of controllers, much of the animation is handled by the Bezier controller. Bezier controllers interpolate between keyframes in a smooth curve. You can adjust the key interpolation of these interpolations through the keys on the track bar or in Track View. This is how you can control acceleration, hesitation and other types of motion.
The default controller for rotation is Euler XYZ, which breaks the rotation down into three individual Bezier Float tracks. The default controller for position is Position XYZ, which is also subdivided into three Bezier Float tracks. The default scale controller is Bezier Scale (comparable to Bezier Float).
3ds Max has a specialized type of controller, called a constraint, that is commonly used to help automate the animation process. You can use a constraint to control an object’s position, rotation, or scale through a binding relationship with another object.
One way to apply constraints and controllers is with commands on the Animation menu. When you assign a controller from this menu, a List controller is automatically applied, with the controller you assigned appearing first in the list. The List controller lets you blend controllers via weighting, similar to a nonlinear animation system. It appears on the Motion panel, which provides special tools for managing the list, but not in Track View. On the other hand, if you assign a controller through the Motion panel or Track View, it replaces the existing controller, rather than creating a List controller. You can do that manually if you are working in the Motion panel or Track View.
This section explains techniques for working with controllers. For details about the parameters and use of each individual controller type, see Animation Controllers.