Parent Constraints in Maya are relatively simple, but it always does some good to completely understand what is going on under the hood, as there may be times when the Parent Constraint will do things that you don’t necessarily want when rigging. As an example, the parent constraint can add another parent constraint node to alread constraint objects, and this might complicate your rigs a bit.
the anatomy of parent constraint and how you can create your own custom constraint using Maya utility nodes
If you understand what the Parent Constraint Tool is doing in Maya, then you can recreate it using Maya’s Utility Nodes, which can provide you to flexibility of customization, catering the tool to your own needs.
CreatureRigs posts a look inside the Maya Parent Constraint tool, and shows some situations that might not be ideal when rigging. Once understanding the parent constraint in Maya, CreatureRigs takes a look at re-creating a Parent Constraint using Maya’s Utility Nodes, and provides the Python code that will build the series of nodes that will act as the constraint.
Check out the tutorial for Creating a Parent Constraint in Maya Using Utility Nodes here.