topic Re: Object Instancing with the Python 1.0 API in Maya Programming Forum

Object Instancing with the Python 1.0 API

aries2 — Sun, 03 Dec 2023 16:30:27 GMT

Hello,

I am exploring the Maya API and testing code to instance an object by parenting a new transform node to the existing shape node:

import maya.OpenMaya as om import maya.OpenMayaMPx as mpx #explicitly get shape node list = om.MSelectionList() om.MGlobal.getSelectionListByName("pCubeShape1",list) shape_node = om.MObject() list.getDependNode(0,shape_node) #create transform node trans_node = om.MFnTransform().create() dag_node = om.MFnDagNode(trans_node) #parent shape node to transform node and instance with 'keepExistingParents' flag dag_node.addChild(shape_node,keepExistingParents=True)

I'm getting the error: 'TypeError: MFnDagNode_addChild() takes no keyword arguments'.

Obviously it's supposed to take this keyword argument and I've seen several example python scripts which do pass this flag to the call.

Any Ideas?

Thanks!

Re: Object Instancing with the Python 1.0 API

brentmc — Mon, 04 Dec 2023 10:17:29 GMT

Hi,

The Python 1.0 API is auto-generated from the C++ API so named arguments are not supported. (and one of the reasons the 2.0 API was developed)

So, in your example you just have to provide an index argument and then a boolean for keepExistingParents like this:

dag_node.addChild(shape_node, 0, True)

Re: Object Instancing with the Python 1.0 API

aries2 — Mon, 04 Dec 2023 10:34:54 GMT

Thanks a lot for your help @brentmc! This now works.

I guess the other examples I saw were based on the 2.0 API.