2009

Animation Constraints
An animation constraint is a special type of controller that can help you
automate the animation process. You can use constraints to control an object’s
position, rotation, or scale through a binding relationship with another object.
A constraint requires an animated object and at least one target object. The
target imposes specific animation limits on the constrained object.
For example, to quickly animate an airplane flying along a predefined path,
you can use a
Path constraint on page 3297 to restrict the airplane’s motion to
a spline.
You can use keyframe animation to toggle the constraint’s binding relationship
with its targets over a period of time.
Common uses for constraints include:
■ Linking one object to another over a period of time, such as a character’s
hand picking up a baseball bat
■ Linking an object’s position or rotation to one or several objects
■ Keeping an object’s position between two or more objects
■ Constraining an object along a path or between multiple paths
■ Constraining an object to a surface
■ Making an object point toward another object
■ Keeping an object’s orientation in relation to another
There are seven types of constraints:
■
Attachment constraint on page 3288 attaches an object’s position to a face
on another object
■
Surface constraint on page 3293 restricts an object’s position along the surface
of another object
■
Path constraint on page 3297 restricts an object’s movement along a path
■ Position constraint on page 3303 causes the constrained object to follow the
position of another object
■
Link constraint on page 3308 links the constrained object from one object
to another
Animation Constraints | 3287