You can have the source objects in a Parent/Child constraint affect only certain axes of a constrained object.
You can constrain an individual axis with the Parent Child constraint. For example you can have an object only parented on its Y-axis.
To constrain individual axes:
- Double-click the Parent/Child constraint in the Scene browser to select it.
- Open the Properties window. The constraint settings display.
- Expand Constraint Axes and disable the X, Y, or Z axis for the desired translation effect you want to inhibit.
- To reactivate the unconstrained axes, activate the option.