1

First time posting here so excuse me if there is an issue with this question.

I have been writing a custom UI addon for blender I have taken out the majority of the code and hopefully kept it as clean as possible to replicate this warning. I often use the console window for debugging and when I am using my plugin the following warning is constantly spammed: 

unable to get Python class for RNA struct 'MAIN_PT_Mainpanel

The simplified code that produces this error is as below:

import bpy
import numpy as np
import mathutils as m
import math
import os


bl_info = {
    "name": "Generation tool",
    "description": "",
    "author": "",
    "version": (0, 0, 4),
    "blender": (2, 80, 0),
    "location": "3D View > Tools",
    "warning": "",  # used for warning icon and text in addons panel
    "wiki_url": "",
    "tracker_url": "",
    "category": "Development"
}

from bpy.props import (StringProperty,
                       BoolProperty,
                       IntProperty,
                       FloatProperty,
                       FloatVectorProperty,
                       EnumProperty,
                       PointerProperty,
                       CollectionProperty
                       )
from bpy.types import (Panel,
                       Menu,
                       Operator,
                       PropertyGroup,
                       )

# ------------------------------------------------------------------------
#    Scene Properties
# ------------------------------------------------------------------------

class MyProperties(PropertyGroup):

    sample_rate: IntProperty(
        name="Samples",
        default=500
    )

# ------------------------------------------------------------------------
#    Panel in Object Mode
# ------------------------------------------------------------------------

class Main_panel(Panel):
    bl_label = "Generation Settings"
    bl_idname = "MAIN_PT_Mainpanel"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = "Generation"
    bl_context = "objectmode"
    @classmethod
    def poll(self, context):
        return context.scene is not None
    def draw(self, context):
        layout = self.layout

class General_sett_subpanel(Main_panel, bpy.types.Panel):
    bl_idname = "SUB_PT_Gensett"
    bl_label = "General Settings"
    bl_parent_id = "MAIN_PT_Mainpanel"

    def draw(self, context):
        layout = self.layout
        scene = context.scene
        mytool = scene.my_tool

        layout.prop(mytool, "sample_rate")

# ------------------------------------------------------------------------
#    Registration
# ------------------------------------------------------------------------

classes = (
    MyProperties,
    Main_panel,
    General_sett_subpanel
)

def register():
    from bpy.utils import register_class
    for cls in classes:
        register_class(cls)
    bpy.types.Scene.my_tool = PointerProperty(type=MyProperties)

def unregister():
    from bpy.utils import unregister_class
    for cls in reversed(classes):
        unregister_class(cls)
    del bpy.types.Scene.my_tool


if __name__ == "__main__":
    register()

I would appreciate any help you can offer me. Thanks in advance!

Sam
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1 Answers1

2

I've coded a fair amount of scripts that use Blender's layout api, but i've never ventured into subpanels. So i may be misunderstanding the intent here.

try

class General_sett_subpanel(bpy.types.Panel):
    bl_idname = "SUB_PT_Gensett"
    bl_label = "General Settings"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_parent_id = "MAIN_PT_Mainpanel"

notice this drops the inheritance of the Mainpanel, but forces you to add bl_space_type and bl_region_type explicitly. I'm not sure it made sense to inherit Mainpanel, the Mainpanel's poll function will determin if the subpanel is displayed anyway.

either way, this does suppress the warning.

zeffii
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