Why doesn't MDagMessage.addMatrixModifiedCallback trigger when rotating the pivot in Maya?

Coding
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1

Hi everyone,

I’m working with Maya’s Python API and trying to monitor changes to an object’s pivot—specifically when the user rotates the pivot using the manipulator.

Here’s the setup I currently have:

from maya import cmds
from maya.api import OpenMaya as om2

index = -1

def update(mobject, flags, clientData):
    if flags & (om2.MDagMessage.kScalePivot | om2.MDagMessage.kRotatePivot):
        print(cmds.manipPivot(q=True, o=True)[0])

def main():
    global index
    node    = om2.MGlobal.getSelectionListByName('pCube1').getDependNode(0) 
    dagPath = om2.MDagPath.getAPathTo(node)
    index   = om2.MDagMessage.addMatrixModifiedCallback(dagPath, update, None)

if __name__ == '__main__':
    main()
    #om2.MEventMessage.removeCallback(index)

This works fine when I move the pivot (e.g. using the Insert key and dragging the pivot), and the callback is triggered as expected. However, when I rotate the pivot using the manipulator, the callback does not fire—even though I’m querying cmds.manipPivot(q=True, o=True) and expecting changes.

Is there a way to detect when the pivot is being rotated interactively? Does Maya expose any event or callback that can be used to track pivot rotation changes?

2

I can repro on 2024.2.1 (PFIX). A pivot rotation doesn’t trigger any event.

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3

I believe the object only has the position of the pivot. The rotation you see is used by the Move/Rotate/Scale tools and I don’t seen any signal that gets sent when it changes. I could just be missing it, but if it’s there somewhere then it would be under OpenMayaUI somewhere, or maybe with the contexts themselves?

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