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Still trying to wrap a property into my Addon where I can dynamically control the values of the resulting variable. Take the default operator_mesh_add example and alter the definition of the width FloatProperty to be: 

def get_func(self):
    print('get_')
    return self.actual_width

def set_func(self, value):
    print('set_')
    self.actual_width = value

class AddBox(bpy.types.Operator):
    """Add a simple box mesh"""
    bl_idname = "mesh.primitive_box_add"
    bl_label = "Add Box"
    bl_options = {'REGISTER', 'UNDO'}

    actual_width: 1.0

    width: FloatProperty(
        name="Width",
        description="Box Width",
        min=0.01, max=100.0,
        default=1.0,
        set=set_func,
        get=get_func,
    )

this gives:

 AttributeError: 'MESH_OT_primitive_box_add' object has no attribute 'actual_width'

if the get/set functions access the self.width member, there is an infinite recursion. We really need a tangible example of how to use get/set within an operator setting.

Following How to use set/get property callbacks correctly? and making set/get:

def get_func(self):
    print('get_')
    return self['width']

def set_func(self, value):
    print('set_')
    self['width'] = value

results in:

KeyError: 'bpy_struct[key]: key "width" not found'

What is the right way?

IRayTrace
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  • self.actual_width doesn't work because you don't have an instance attribute, you've declared a class attribute. Therefore you would need to use either AddBox.actual_width or type(self).actual_width. – Robert Gützkow Oct 15 '19 at 22:06
  • The proper way for most use cases would be through the key based access. See: https://blender.stackexchange.com/questions/126458/internal-get-set-function-of-property The important difference is the use of .get() for when the key doesn't yet exist. – Robert Gützkow Oct 15 '19 at 22:13

0 Answers0