When you bind skin, Maya creates a bind pose node (default name: bindPosen) for each skeleton. For each skeleton, the bind pose node keeps track of the joints’ transformation attributes (translation, rotation, and scale) when skinning takes place. The bind pose node also keeps track of the transformation attributes of any influence objects. The bind pose node facilitates putting the skeleton back into the bind pose at any time after binding skin.
The use of constraints, expressions, or IK handles with keys set can restrict going to the bind pose. If you are using constraints, expressions, or IK handles and you want to go back to the bind pose, you will need to disable the nodes that carry out these features. They can restrict going to bind pose because they can lock the attributes they affect, preventing them from being set to the bind pose values.
