There's this free addon that allows creation of custom driven properties from shapekeys automatically using python by selecting the mesh then the bone you want to assign the custom properties in pose mode and clicking generate.

There's a few issues I've encountered:

  1. whenever you generate the custom properties, the min and max value are set to -inf and inf respectifely instead of 0 and 1. It is hectic to change them after generation especially when alot of shapekeys are involved.
  2. The generated custom properties won't control the shapekeys unless you reload the dependecies.

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I'm using blender 3.5

Shapekeys to customprops addon

Here's a link to the addon: https://github.com/theoldben/ShapekeysToCustomProperties

Here's the full code of the addon

### Create Custom Properties on an Armature that drive all Shape Keys on its Child Mesh ###

# Select the Mesh with the Shape Keys on it, then select the Armature that is to hold 
# the Custom Properties with which you are going to drive the ShapeKeys and run

bl_info = {
    "name": "ShapeKeys to Driven Armature Properties",
    "author": "crute, DR",
    "version": (1, 0),
    "blender": (2, 90, 0),
    "location": "View3D > Property Panel > Item Tab",
    "description": "Adds Shapekeys from a Mesh Object as Driven Custom Properties to an Armature",
    "warning": "",
    "doc_url": "https://github.com/theoldben/ShapekeysToCustomProperties",
    "category": "Rigging",

import bpy

# Error in case Selection does not meet requirements
def error_selection(self, context):
    self.report({'WARNING'}, 'Incorrect Object Selection: Please Select a Mesh Object followed by an Armature Object')
    return {'FINISHED'}

def main(context):

class OBJECT_OT_ShapeKeysToDrivenProps(bpy.types.Operator):
    """ShapeKeys to Driven Armature Properties"""
    bl_idname = "object.shapekeystodrivenprops"
    bl_label = "ShapeKeys to Driven Armature Properties"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = 'Item'
    bl_options = {'REGISTER', 'UNDO'}
    def poll(cls, context):
        return context.active_object is not None

    def execute(self, context):

        # Variable Definition
        context = bpy.context
        obj = bpy.context.object
        active_obj = bpy.context.active_object
        selected_obj = bpy.context.selected_objects
        other_obj =  [obj for obj in bpy.context.selected_objects if obj.type == 'MESH']
        active_bone = bpy.context.active_pose_bone

            active_bone_name = active_bone.name
            key_number = len(other_obj[0].data.shape_keys.key_blocks)

            # Check for Object type: Active Object: Armature, Selected Object: Mesh
            if len(selected_obj) == 2 and active_obj.type == 'ARMATURE' and other_obj[0].type == 'MESH':

                # If other objects are in selection: return Error
                for things in selected_obj:

                    # Iterate over ShapeKey List, Store Names, Add Properties to Active Object, 
                    for i in range(1, key_number):
                        # Store ShapeKey Name
                        name_shapekey = other_obj[0].data.shape_keys.key_blocks[i].name
                        #Strip current Shapekey Name of all alpha-numerical characters
                        alphanumeric_filter = filter(str.isalnum, name_shapekey)
                        alphanumeric_string = "".join(alphanumeric_filter)
                        clean_name_shapekey = alphanumeric_string

                        # Access RNA_UI Dictionary of PoseBone, create if it does not exist
                        if "_RNA_UI" not in active_bone.keys():
                            active_bone['_RNA_UI'] = {}
                        act_bone_rna_ui = active_bone.get('_RNA_UI')

                        # If there is already a property with the current shapekey's name, skip
                        if name_shapekey in act_bone_rna_ui:
                        # Add Property with ShapeKey's name to Active PoseBone and set Value to 0
                        active_bone[name_shapekey] = 0.0
                        # active_bone['_RNA_UI'].update({name_shapekey : 0.0})
                        # Add Custom Properties to RNA_UI dictionary, fill values
                        active_bone['_RNA_UI'].update({name_shapekey : 
                                                            "default": 0.0,
                                                            "description":"Shape Key Influence",
                        act_bone_rna_ui[name_shapekey]["min"] = 0.0
                        act_bone_rna_ui[name_shapekey]["max"] = 1.0

                        # Add the Drivers to the ShapeKeys Value Field, so ttheir influence can be controlled via Custom Properties                  
                        driver = other_obj[0].data.shape_keys.key_blocks[i].driver_add("value").driver
                        # Create new input Variable for driver
                        driver_var = driver.variables.new()
                        driver_var.name = clean_name_shapekey
                        # Set number of Variables in the driver stack, since there is only one, that is 0
                        target = driver_var.targets[0]
                        # Set the Target object for the Driver's Variable Input, i.e. the Armature Object, where the input sliders are
                        target.id = active_obj
                        # Set the drivers Data Path, i.e. the RNA Path to the Property it uses as input
                        target.data_path = "pose.bones"+"["+"\""+active_bone.name+"\""+"]"+"[" +"\""+ name_shapekey + "\"" +"]"
                        # Set the Expression Field of the Driver, in this case with the sanitised variable name
                        driver.expression = driver_var.name
                        # Jiggle the driver to force update
                        driver.expression += " "
                        driver.expression = driver.expression[:-1]

                # Set ShapeKey Startup Value
                other_obj[0][name_shapekey] = 0.0

                # property attributes.for UI
                # redraw Properties panel
                for window in bpy.context.window_manager.windows:
                    screen = window.screen

                    for area in screen.areas:
                        if area.type == 'PROPERTIES':

                    for area in screen.areas:
                        if area.type == 'UI':

                return {'FINISHED'}
                error_selection(self, context)

            error_selection(self, context)
        return {'FINISHED'}

class PANEL_PT_ShapeKeysToDrivenProps(bpy.types.Panel):
    """ShapeKeys to Driven Armature Properties"""
    # bl_idname = "panel.shapekeystodrivenprops"
    bl_label = "ShapeKeys to Driven Armature Properties"
    bl_space_type = "VIEW_3D"
    bl_region_type = "UI"
    bl_category = 'Item'
    bl_options = {'DEFAULT_CLOSED'}

    def draw(self, context):
        self.layout.operator("object.shapekeystodrivenprops", text="ShapeKeysToDrivenProps")

def register():

def unregister():

if __name__ == "__main__":

Thank you in advance!

  • $\begingroup$ That should be reported to the addon author rather than here since it's a third-party addon. $\endgroup$
    – John Eason
    Commented Aug 22, 2023 at 9:16
  • $\begingroup$ I've tried contacting him but it seems the addon is no longer in development. It's a free addon and it's also free to alter and redistribute according to blender's license. $\endgroup$ Commented Aug 22, 2023 at 9:27
  • $\begingroup$ Fair enough. I see that it was last accessed by the author 3 years ago so he may not even be using Blender now! This Q&A site isn't really for requests to update addon code though, so you may not get any response here. $\endgroup$
    – John Eason
    Commented Aug 22, 2023 at 9:37
  • $\begingroup$ I'm more into finding how I could make the custom properties min and max values default to 0 and 1 after generation. The addon is not broken, it's just that tiny bug that needs fixing, I just don't know how. I've been trying to fix it since 2021 $\endgroup$ Commented Aug 22, 2023 at 10:38
  • $\begingroup$ The API has changed some versions ago. You should now use id_properties_ui to control min and max attributes $\endgroup$
    – Gorgious
    Commented Aug 22, 2023 at 11:48


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