[x3d-public] Question about a Python and x3d.py Error message

Wed Jan 15 09:24:59 PST 2025

Hey guys, "please don't go there."  You should never need to poke around with __init__ or inheritance or any of that internal stuff.  Those code patterns are autogenerated, so you don't have to do any of that.

Just build a scene graph.  The vocabulary is simply X3D.

Corrolary:   "creativity is punished"   😨

all the best, Don

--

Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu

Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA    +1.831.656.2149

X3D graphics, virtual worlds, navy robotics https://faculty.nps.edu/brutzman

________________________________
From: x3d-public <x3d-public-bounces at web3d.org> on behalf of Bergstrom, Aaron via x3d-public <x3d-public at web3d.org>
Sent: Wednesday, January 15, 2025 9:03 AM
To: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>
Cc: Bergstrom, Aaron <aaron.bergstrom at und.edu>
Subject: Re: [x3d-public] Question about a Python and x3d.py Error message

Apparently, I’m a bit out of my depth when it comes to multi class inheritance. Not really a good tutorial out there for mixing inheritance from Maya python classes and other classes. I’m getting another error now.

“'X3DScene' object has no attribute '_Scene__children'”

Looking up similar errors in Google basically tells me I’m not calling the inherited classes __init__ methods.

I’ll have to do some more digging.

From: John Carlson <yottzumm at gmail.com>
Sent: Wednesday, January 15, 2025 10:52 AM
To: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>
Cc: Bergstrom, Aaron <aaron.bergstrom at und.edu>
Subject: Re: [x3d-public] Question about a Python and x3d.py Error message

self is the first parameter to instance methods.  I don’t know about class methods.  My guess is you might want instance methods, but it’s your design.

On Wed, Jan 15, 2025 at 10:37 AM Bergstrom, Aaron via x3d-public <x3d-public at web3d.org<mailto:x3d-public at web3d.org>> wrote:

John,

Thanks for responding.

So in the case of the code below, would the instance method be the “def creator(cls):” method? If so, would I think do the following: “def creator(cls, self):”

Or am I not understanding what you are saying?

Thanks,

Aaron

From: John Carlson <yottzumm at gmail.com<mailto:yottzumm at gmail.com>>
Sent: Wednesday, January 15, 2025 10:12 AM
To: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org<mailto:x3d-public at web3d.org>>
Cc: Bergstrom, Aaron <aaron.bergstrom at und.edu<mailto:aaron.bergstrom at und.edu>>
Subject: Re: [x3d-public] Question about a Python and x3d.py Error message

Aaron, AFAIK, you need “self” as the first parameter in your instance methods (not functions, of course).  I don’t know about class methods.

If you’re familiar with Java or C++, this is similar to “this”.

On Wed, Jan 15, 2025 at 10:02 AM Bergstrom, Aaron via x3d-public <x3d-public at web3d.org<mailto:x3d-public at web3d.org>> wrote:

I need help troubleshooting a x3d.py error message.

In developing a Python version of the Rawkee X3D exporter plugin for Maya, I am attempting to create nodes that inherit from both the Maya Python API 2.0 and x3d.py

As such, I have a question about python and multiple class inheritance, and an error I am seeing. Admittedly, I am not the strongest Python programmer.

I am getting the following error when I execute the Python code in Maya, and I’m pretty sure I do not of the __init__() function setup correctly.

# Error: TypeError: file C:\Users\user.name<http://user.name/>\AppData\Roaming\Python\Python311\site-packages\x3d\x3d.py line 14984: Scene.hasChild() missing 1 required positional argument: 'self' #

Can anyone with some Python experience give me an idea of what I am doing wrong here?

Here is the code:

#################################################################

import x3d

import maya.api.OpenMaya as aom

import maya.api.OpenMayaUI as aomui

import maya.api.OpenMayaRender as aomr

# import xmltodict

# import json

class X3DScene (aom.MPxNode, x3d.Scene):

    TYPE_NAME    = "Scene"

    TYPE_ID      = aom.MTypeId(0x00108FFF)

    PROFILE_TYPE = "Full"

    VERSION      = "4.0"

    def __init__(self):

        super(X3DScene, self).__init__()

    @classmethod

    def creator(cls):

        return X3DScene()

    @classmethod

    def initialize(cls):

        cls.x3dDoc = x3d.X3D(profile=cls.PROFILE_TYPE, version=cls.VERSION)

        cls.x3dDoc.Scene = cls

        #######################################################

        # Test dump to make sure the class works as expected

        #print(json.dumps(xmltodict.parse(cls.x3dDoc.XML()), indent=4))

        print(cls.x3dDoc.XML())

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