Shape Key: Delete Specific Driver

Question

I'm trying to delete the driver of specific shape keys. I have used the code below, which deletes a shape key, using key_idx to select an entry key from the list.

fcurves.remove(fcurves[key_idx])

However, the 'index' values of that list are defined by the drivers rather than the shape keys. That is to say, fcurves.remove(fcurves[3]) will find the third shape-key-with-a-driver, and not the driver of the third shape key.

This means that I can't use key_idx = active_shape_key_index to delete a specific shape key, since I've no way of telling how many previous shape keys have drivers, if any.

There's also bpy.ops.anim.driver_button_remove(all=True), but that just returns {'CANCELLED'}

How can I specify a shape key driver to be deleted, when it's unknown at what 'driver index' that driver sits at?

Answer 1

Remove shape key and key driver by shape key index

import bpy

def kill_shape_key_by_ind(oj, ind):
    shape_keys = oj.data.shape_keys
    blocks = shape_keys.key_blocks

    if ind >= len(blocks):
        print("Out of index")
        return

    shape_key = blocks[ind]
    shape_key_name = shape_key.name

    drivers = shape_keys.animation_data.drivers
    dr = drivers.find(f'key_blocks["{shape_key_name}"].value')
    if dr is not None:
        drivers.remove(dr)

    ind = blocks.keys().index(shape_key_name)
    # set active shape key index before remove
    oj.active_shape_key_index = ind

    context_object = bpy.context.object
    bpy.context.view_layer.objects.active = oj
    bpy.ops.object.shape_key_remove()
    bpy.context.view_layer.objects.active = context_object


kill_shape_key_by_ind(bpy.data.objects["Cube"], 3)