Python Error When Enabling Add-on Regarding CardanAngles Field Not Being Allowed

by ADMIN 81 views

Introduction

Blender is a popular 3D creation software that offers a wide range of features and tools for modeling, rigging, animation, and rendering. One of the key features of Blender is its ability to support add-ons, which are third-party plugins that can extend the functionality of the software. However, sometimes, enabling an add-on can result in a Python error, which can be frustrating and difficult to resolve. In this article, we will explore a specific Python error that occurs when enabling an add-on regarding the CardanAngles field not being allowed.

Describe the Bug

After successfully installing the add-on and then enabling it for the first time, I receive a Python error stating the following:

mutable default <class 'rbr_track_formats.dls.trigger_data.CardanAngles'> for field unused_angles is not allowed: use default_factory

This error occurs when trying to enable the add-on, and it prevents the add-on from functioning correctly. The error message suggests that the issue is related to the CardanAngles field, which is a part of the trigger_data module in the rbr_track_formats.dls package.

To Reproduce

To reproduce the behavior, follow these steps:

  1. Download add-on ZIP file: Download the add-on ZIP file from the official Blender website or from a trusted source.
  2. Drag downloaded ZIP file into Blender 4.3 window: Drag the downloaded ZIP file into the Blender 4.3 window. You can also use the "Install from File" option in the Blender preferences to install the add-on.
  3. Enable add-on if not already enabled: Enable the add-on by clicking on the "Enable" button in the Blender preferences.
  4. Observe Python error thrown: Observe the Python error that is thrown when trying to enable the add-on.

Expected Behavior

The expected behavior is that the add-on is successfully enabled with no errors thrown. The add-on should function correctly, and you should be able to use its features without any issues.

Screenshots

Unfortunately, there are no screenshots available to help explain the problem.

Desktop (please complete the following information):

  • OS: Windows 11
  • Blender version: 4.3.2
  • Addon version: 0.31

Additional Context

The full error message is as follows:

Python: Traceback (most recent call last):
  File "C:\Program Files\Blender Foundation\Blender 4.3\4.3\scripts\addons_core\bl_pkg\bl_extension_ops.py", line 1481, in execute
    cmd_batch = self.exec_command_iter(is_modal)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Program Files\Blender Foundation\Blender 4.3\4.3\scripts\addons_core\bl_pkg\bl_extension_ops.py", line 2560, in exec_command_iter
    self.exec_legacy(source_filepath)
  File "C:\Program Files\Blender Foundation\Blender 4.3\4.3\scripts\addons_core\bl_pkg\bl_extension_ops.py", line 2692, in exec_legacy
    bpy.types.PREFERENCES_OT_addon_install.execute(self, bpy.context)
  File "C:\Program Files\Blender Foundation\Blender 4.3\4.3\scripts\startup\bl_operators\userpref.py", line 813, in execute
    bpy.ops.preferences.addon_enable(module=mod.__name__)
  File "C:\Program Files\Blender Foundation\Blender 4.3\4.3\scripts\modules\bpy\ops.py", line 109, in __call__
    ret = _op_call(self.idname_py(), kw)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Error: mutable default <class 'rbr_track_formats.dls.trigger_data.CardanAngles'> for field unused_angles is not allowed: use default_factory

Troubleshooting

To troubleshoot this issue, you can try the following:

  1. Check the add-on version: Make sure that you are using the latest version of the add-on.
  2. Check the Blender version: Make sure that you are using the latest version of Blender.
  3. Check the Python version: Make sure that you are using the latest version of Python.
  4. Check the add-on dependencies: Make sure that the add-on has all the necessary dependencies installed.
  5. Try disabling and re-enabling the add-on: Try disabling and re-enabling the add-on to see if the issue persists.

Conclusion

Introduction

In our previous article, we explored a Python error that occurs when enabling an add-on regarding the CardanAngles field not being allowed. This error can be frustrating and difficult to resolve, especially for users who are new to Blender and add-ons. In this article, we will provide a Q&A section to help users understand the issue and find a solution.

Q: What is the CardanAngles field?

A: The CardanAngles field is a part of the trigger_data module in the rbr_track_formats.dls package. It is used to store the Cardan angles, which are a set of angles used to describe the orientation of an object in 3D space.

Q: What is the error message trying to tell me?

A: The error message is trying to tell you that the mutable default for the CardanAngles field is not allowed. This means that the field is trying to use a mutable default value, which is not allowed in Python.

Q: What is a mutable default value?

A: A mutable default value is a value that can be changed after it is created. In Python, mutable default values are not allowed because they can cause unexpected behavior.

Q: How can I fix the error?

A: To fix the error, you can try the following:

  1. Check the add-on version: Make sure that you are using the latest version of the add-on.
  2. Check the Blender version: Make sure that you are using the latest version of Blender.
  3. Check the Python version: Make sure that you are using the latest version of Python.
  4. Check the add-on dependencies: Make sure that the add-on has all the necessary dependencies installed.
  5. Try disabling and re-enabling the add-on: Try disabling and re-enabling the add-on to see if the issue persists.

Q: I have tried all the above steps, but the error still persists. What can I do?

A: If you have tried all the above steps and the error still persists, you can try the following:

  1. Contact the add-on developer: Reach out to the add-on developer and ask for help. They may be able to provide a solution or fix the issue.
  2. Seek help from the Blender community: Join the Blender community and ask for help. Other users may have experienced the same issue and can provide a solution.
  3. Try a different add-on: If the issue is specific to the add-on, you can try using a different add-on that does not have the same issue.

Q: Can I prevent this error from occurring in the future?

A: Yes, you can prevent this error from occurring in the future by:

  1. Checking the add-on version: Make sure that you are using the latest version of the add-on.
  2. Checking the Blender version: Make sure that you are using the latest version of Blender.
  3. Checking the Python version: Make sure that you are using the latest version of Python.
  4. Checking the add-on dependencies: Make sure that the add-on has all the necessary dependencies installed.

Conclusion

In conclusion, the Python error that occurs when enabling an add-on regarding the CardanAngles field not being allowed is a frustrating issue that can prevent the add-on from functioning correctly. By following the troubleshooting steps outlined above, you should be able to resolve the issue and enable the add-on successfully. If you are still experiencing issues, you can try seeking help from the Blender community or the add-on developer.