[Maya Python API] lodGroup node creation slow/deferred?

Coding
1

Here is something interesting. If you try to parent an existing object (on user select for example) to a newly created transform node by running the code below all at once, everything works fine.

import maya.OpenMaya as api

DGMod = api.MDagModifier()
nO = DGMod.createNode('transform')
nFn = api.MFnDagNode(nO)
nFn.setName('TAO')
DGMod.doIt()
# ---------------------------------------------
selection = api.MSelectionList()
api.MGlobal.getActiveSelectionList(selection)
selectionObjList = api.MObjectArray()
for i in range(selection.length()):
    mObj = api.MObject()
    selection.getDependNode(i, mObj)
    selectionObjList.append(mObj)
# ---------------------------------------------
for i in range(selectionObjList.length()):
    DGMod.reparentNode(selectionObjList[i], nO)
DGMod.doIt()

Now replace node type to ‘lodGroup’ and run entire code again - it will actually crash Maya.
Now try to run it a code block at a time - works fine…

Edit: Confirmed on versions 2011 - 2014
Edit: Confirmed on both sets of api (maya.OpenMaya & maya.api.OpenMaya)

Any thoughts?
Cheers!

2

I’ve tried other ways of creating a node like via MFnDagNode.create() method or even wrapping the creation into a method which calls ‘createNode’ MEL command through MGlobal.executeCommand().
Also tried putting in an artificial pause between creation and parenting via time.sleep() method.
Nothing works. Maya crashes every time.

3

Hmm… Attaching to process yielded unhandled exception due to null pointer reference in ModelSlice.dll

Unhandled exception at 0x000007fce4593d3c in maya.exe: 0xC0000005: Access violation reading location 0x0000000000000000.

Are dag modifier calls processed asynchronously?

4

Figured it out… Calling M3dView.refresh() after node creation seems to fix it.