Description of how one could retrieve the "edits" for referenced nodes (draft implementation)

maya_extract_edits.py

"""This is a first draft template that could be used to retrieve the edits on referenced nodes that define a look

Next step would be to filter the edits of interest, like shader assignments, sets they are added to, attributes that were added or changed in value.
Then we need to store these changes in a format that is artist-friendly and can be re-applied in another scene.

"""

import maya.cmds as mc
from collections import defaultdict


def extract_edits(nodes):
    """Return a dictionary of data related to the look
    
    The given `nodes` must all be referenced nodes.
    
    Arguments:
        nodes (list): The nodes to retrieve the edits for.

    Returns:
        dict: Dictionary holding the edits to the nodes
            that define the look.

    """
    
    # Only allow referenced nodes
    assert all(mc.referenceQuery(n, isNodeReferenced=True) for n in nodes)
    
    # Store each node per reference node they belong to
    ref_nodes = defaultdict(list)
    for node in nodes:
        ref = mc.referenceQuery(node, referenceNode=True)
        ref_nodes[ref].append(node)
        
    # Get the reference edits for per reference node
    ref_edits = {}
    for ref in ref_nodes:
        # All succesfull edits with their long names
        edits = mc.referenceQuery(ref, 
                                  editStrings=True, 
                                  showNamespace=True, 
                                  showDagPath=True, 
                                  failedEdits=False)
        ref_edits[ref] = edits
    
    # Filter edits to those that apply solely to our
    # subset of nodes instead of all that are in the
    # referenced scene.
    for ref, nodes in ref_nodes.iteritems():
        edits = ref_edits[ref]
        
        for edit in edits:
            # TODO: Filter to edits that belong to 'nodes'
            # TODO: Filter the edits we actually want?
            print edit

if __name__ == "__main__":
    extract_edits(mc.ls(sl=1))