Nodes with unique IDs

README.md

Nodes with unique IDs in Maya

unique_id1.py associates a new ID to every DAG-node in the scene, unique_id2.py does the same but keeps existing IDs as-is. Finally, unique_id3.py updates IDs and ensures that no duplicate ID exists in the scene.

unique_id1.py

"""Assign a unique identifier to ever DAG node within Maya

The problem: existing IDs are discarded.

"""

import uuid
from maya import cmds


def update_id():
    """Update the unique identifier of every node"""
    for node in cmds.ls(dag=True):
        attribute = node + ".uuid"

        if not cmds.objExists(attribute):
            cmds.addAttr(node,
                         longName="uuid",
                         dataType="string")

        new_id = str(uuid.uuid4())
        cmds.setAttr(attribute, new_id, type="string")


update_id()

unique_id2.py

"""Assign a unique identifier to ever DAG node within Maya

The problem: there may be duplicate IDs

"""

import uuid
from maya import cmds


def update_id():
    """Update the unique identifier of every node"""
    ids = list()
    for node in cmds.ls(dag=True):
        attribute = node + ".uuid"
        if not cmds.objExists(attribute):
            cmds.addAttr(node,
                         longName="uuid",
                         dataType="string")
            cmds.setAttr(attribute, str(uuid.uuid4()), type="string")


update_id()

unique_id3.py

"""Assign a unique identifier to ever DAG node within Maya

Also keep existing ID's and update any duplicates.

"""

import uuid
import time
from maya import cmds


def generate_id():
    return str(uuid.uuid4())


def test_uniqueness():
    ids = list()
    for attr in cmds.ls("*.uuid"):
        id = cmds.getAttr(attr)
        assert id not in ids
        ids.append(id)


def update_id():
    """Update the unique identifier of every node"""
    start = time.time()
    
    ids = list()
    for node in cmds.ls(dag=True):
        attribute = node + ".uuid"
        if not cmds.objExists(attribute):
            cmds.addAttr(node,
                         longName="uuid",
                         dataType="string")
            new_id = generate_id()
            ids.append(new_id)
            print "No id: %s - creating" % node
        else:
            # Look for duplicate IDs
            existing_id = cmds.getAttr(attribute)
            if not existing_id in ids:
                ids.append(existing_id)
                print "Existing unique id: %s" % node
                continue

            new_id = generate_id()
            print "Duplicate id: %s - updating" % node

        print "Setting the attribute on %s" % node
        cmds.setAttr(attribute, new_id, type="string")

    end = time.time()
    test_uniqueness()
    print "Update took: %.3f ms" % ((end - start) * 1000)


update_id()