This Maya tool deletes all shape nodes from the a list of selection, and replaces those shapes with the shape node of the last selected object, turning all objects into instances of the last object

duplicatesToInstances_v01_04.py

'''
---
Duplicates to Instances
version: v01_04
date: 20161031
Written by: Patrick Woo
[email protected]
---

Description:
This tool takes a list of objects, use the shape node of the last selected object,
and turn it into an instance to the rest of the objects in the list.

changelog:
- using str values for names and paths, and PyNode() to refer to scene objects 
    only at the point of need
'''

from pymel.core import *
import maya.mel as mm

infoStr = '''
---
Duplicates to Instances
version: v01_04
date: 20161031
Written by: Patrick Woo
[email protected]
---

Description:
This tool takes a list of objects, use the shape node of the last selected object,
and turn it into an instance to the rest of the objects in the list.
'''

def parseLongName(longNameIn):
    '''
    takes a maya long name (full path) as a str and returns the path and name as strings
    
    longNameIn - <str> example: u'|streamerConstruction_grp|waistStreamerConstruct_grp'
    
    return - <dict> {'path': <str>path, 'name': <str>shortName} 
    '''
    path = longNameIn[:longNameIn.rfind('|')] # longNameIn up to the last '|'
    shortName = longNameIn[longNameIn.rfind('|')+1:] # from the last '|' to the rest of longNameIn
    return {'path': path, 'name': shortName}

def dupsToInstances(sel):
    '''
    this tool deletes all shape nodes from the a list of selection, 
    and replaces those shapes with the shape node of the last selected object,
    turning all objects into instances of the last object

    the tool assumes that for each of the instances there are no further group hierarchies 
    parented under them.
    '''
    gMainProgBar = mm.eval('$tmp = $gMainProgressBar') # get main progress bar
    progressBar(gMainProgBar, e=True, endProgress=True)
    
    msgNoShapes = 'Please select objects with shape nodes before running the script. Aborted' 
    if not sel:
        print 'dupsToInstances:', msgNoShapes
        return
    shapesList = []
    for x in sel:
        adShapesList = listRelatives(x, ad=True, type='shape')
        if adShapesList:
            shapesList += [i for i in adShapesList if i not in shapesList]
        elif 'shape' in nodeType(x, i=True):
            shapesList += list(x) if x not in shapesList else [] # putting x in a list is intentional  
    shapesList = [i.name() for i in listRelatives(sel, ad=True, type='shape')]
    if not shapesList:
        print 'dupsToInstances:', msgNoShapes
        return
    if len(shapesList) < 2:
        msgNotEnoughObjs = 'Please select more than one object to make them instances. Aborted'
        print 'dupsToInstances:', msgNotEnoughObjs 
        return

    # all prerequisites fulfilled
    try: 
        timer(n='dupsToInstanceTimer', e=True) # in case the timer was previously started
    except:
        pass
    
    lastObjName = PyNode(shapesList[-1]).getParent().name()
    mainTransform = duplicate(PyNode(shapesList[-1]))[0]
    parent(mainTransform, None)
    # print 'mainshape is', mainTransform
    mainShape = mainTransform.getShape()
    # print 'mainshape is', mainShape
    xformList = [PyNode(x).getParent().name() for x in shapesList]
    print 'dupsToInstances: selection has %i objects, %i shape nodes' % (len(shapesList), len(xformList))

    timer(n='dupsToInstanceTimer', s=True) # start timer

    gMainProgBar = mm.eval('$tmp = $gMainProgressBar') # get main progress bar
    progAmt = 0
    progressBar(gMainProgBar, e=True, beginProgress=True, 
                maxValue=len(xformList), isInterruptable=True)
    
    totalLenNumObjs  = len(xformList)
    newXformList = []
    # delGrp = group(name='toBeDeleted_grp', empty=True)
    timing = 0 # stores the time taken for dupsToInstanceTimer 
    while xformList:
        # print 'dupsToInstances: xformList (len %i) is %s' % (len(xformList), xformList)
        obj = PyNode(xformList[0])
        tmpObj = duplicate(mainTransform, instanceLeaf=True)[0] # duplicate as instance
        parent(tmpObj, obj.getParent())
        xform(tmpObj, ws=True, a=True, m=xform(obj, q=True, ws=True, a=True, m=True))
        assumeName = obj.name()
        obj.rename(obj.name()+'_toDelete')
        # print 'dupsToInstances: ori obj renamed to', obj.name()
        tmpObj.rename(assumeName)
        # print 'dupsToInstances: tmpObj renamed to', tmpObj.name()
        if len(xformList) >= 1:
            xformList = xformList[1:]
            shapesList = shapesList[1:]
        else:
            xformList = []
            shapesList = []
        # print 'dupsToInstances: pre-delete', obj
        delete(obj)
        del obj
        newXformList.append(tmpObj.name())
        # print 'dupsToInstances: newXformList (len %i) is %s' % (len(newXformList), newXformList)

        progressBar(gMainProgBar, e=True, step=1, 
                    status='processing %s. %s out of %s.' % (newXformList[-1], progAmt, totalLenNumObjs) )        
        if progressBar(gMainProgBar, q=True, isCancelled=True):
            print 'dupsToInstances: Operation aborted & incomplete. Converted %i out of %i to instances. UNDO IS RECOMMENDED.' % (progAmt, len(xformList))
            progressBar(gMainProgBar, e=True, endProgress=True)
            timing = timer(n='dupsToInstanceTimer', e=True)
            # break
            return
        if progAmt > totalLenNumObjs:
            progressBar(gMainProgBar, e=True, endProgress=True)
            timing = timer(n='dupsToInstanceTimer', e=True)
            break

        progAmt += 1
    # end for obj

    progressBar(gMainProgBar, e=True, endProgress=True)
    # if progressBar(gMainProgBar, q=True, progress=True) >= progressBar(gMainProgBar, q=True, maxValue=True):
    #     progressBar(gMainProgBar, e=True, endProgress=True)
    #     break

    if timing == 0:
        timing = timer(n='dupsToInstanceTimer', e=True)
    # delete(delGrp)
    select(newXformList, replace=True)
    print 'dupsToInstances: operation finished in %0.2fs (%0.2fmins)' % (timing, timing/60.0)
    print 'dupsToInstances: %i objects have been converted to instances of %s' % (len(ls(sl=True)), lastObjName)
    delete(mainTransform)
    del xformList, shapesList
    print ''
    return

print infoStr
dupsToInstances(ls(sl=True))