Assigns the rotation
transformation of the null (or joints) elements in the hierarchy
that are used as pre-rotation and post- rotation to the joint orient and
the rotate axis of the original node.
The pre-rotation and
post-rotation nodes are then deleted.
The look-up is done by
name as the pre-rotation node's name contains the “__Pre_ “suffix,
while the post-rotation node's name has a “__Post_” suffix.
When the import mode is set to Exmerge or Merge this
option is automatically set to True.