Main toolbar > Open Track View > Select a scale track in the Track View Hierarchy > Track View toolbar > Assign Controller > Scale XYZ
Graph Editors > Track View > Open Track View > Select a scale track in the Track View Hierarchy > Track View toolbar > Assign Controller > Scale XYZ
The Scale XYZ controller has independent float controllers for each scale axis of an object's transform. With three separate tracks for scale, you can create scale keys for each axis independently, change interpolation settings for a single axis, or assign a controller on an axis. For example, after applying a Scale XYZ controller, you could apply a Noise controller to an axis to animate that axis independently.
Tip: Open Track View to view and edit the three scale tracks.
Procedure
Example: To assign the Scale XYZ controller to an object:
In the Top viewport, create a sphere.
Right-click over the sphere and choose Track View Selected in the dialog.
In the Track View Hierarchy, expand the Sphere01, and, then select the Scale track.
On the Track View toolbar, click Assign Controller and select Scale XYZ.
In the Track View Hierarchy, expand the Scale track.
Three tracks are displayed and are available to control the object's scale.
In the Track View Hierarchy, select the Z Scale, click Assign Controller on the Track View toolbar, and then choose Noise Float from the dialog.
Click Play. The sphere scales along the Z axis, controlled by the Noise controller.
Interface
After applying the Scale XYZ controller to an object, Scale XYZ parameters appear in a rollout on the Motion panel.
Scale Axis: Adjusts and axis using controls in the Motion panel > Key Info rollout.
An axis should already have a key to adjust. To create keys, either turn on Animate and scale the object, or, click Scale in the Create Key group on the PRS Parameters rollout.