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 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

Tip: You can use Schematic View to see all the Constraint relationships in a scene.

Using Constraints with Bones

Constraints can be applied to bones as long as an IK controller is not controlling the bones. If the bones have an assigned IK controller, you can only constrain the root of the hierarchy or chain.