Parent Constraint (Matrix3 Controller)
The Parent Constraint overrides the behaviour from the normal parenting, so you can have a node that is parented to an object, but behaves as if it were parented to a different one. It can also have several nodes as parents with different weights for how much those objects affect the parenting.
Interface
Once you assign a Parent Constraint, you can access its properties on the Parent Constraint rollout on the Motion panel.
Add Parent Target
Adds new target objects that influence the constrained object.
Add World as Target
Parents the constrained object to the world axis. You can weight the amount of influence that the world target has on the constrained object as you would any other target object.
Delete Parent Target
Remove targets. Once removing the target, it will no longer influence the constrained object.
[target list]
Shows the targets and their weights.
Weight
Assigns and animates weight values for each target.
Keep Initial Offset
Preserves the original transform of the constrained object. When you turn off Keep Initial Offset, the object adjusts itself to match the transform of its target or targets. Default=off.