Blender remove empty Vertex Groups and Shape Keys

blender_remove_garbage.py

## Remove empty vertex groups and shape keys
## Credits:
##    https://blender.stackexchange.com/questions/237599/is-there-a-way-to-automatically-delete-shape-keys-that-are-identical-to-the-basi
##    https://blender.stackexchange.com/questions/16517/how-to-quickly-remove-all-zero-weight-vertex-groups

import bpy
import numpy as np

# Tolerance to small differences, change it if you want
tolerance = 0.001

assert bpy.context.mode == 'OBJECT', "Must be in object mode!"

def survey(obj):
    maxWeight = {}
    for i in obj.vertex_groups:
        maxWeight[i.index] = 0

    for v in obj.data.vertices:
        for g in v.groups:
            gn = g.group
            w = obj.vertex_groups[g.group].weight(v.index)
            if (maxWeight.get(gn) is None or w>maxWeight[gn]):
                maxWeight[gn] = w
    return maxWeight

for obj in bpy.context.selected_objects:
    if obj.type != 'MESH': continue
    if not obj.data.shape_keys: continue
    if not obj.data.shape_keys.use_relative: continue

    kbs = obj.data.shape_keys.key_blocks
    nverts = len(obj.data.vertices)
    to_delete = []

    # Cache locs for rel keys since many keys have the same rel key
    cache = {}

    locs = np.empty(3*nverts, dtype=np.float32)

    for kb in kbs:
        if kb == kb.relative_key or 'vrc.v_' in kb.name:
            continue

        kb.data.foreach_get("co", locs)

        if kb.relative_key.name not in cache:
            rel_locs = np.empty(3*nverts, dtype=np.float32)
            kb.relative_key.data.foreach_get("co", rel_locs)
            cache[kb.relative_key.name] = rel_locs
        rel_locs = cache[kb.relative_key.name]

        locs -= rel_locs
        if (np.abs(locs) < tolerance).all():
            to_delete.append(kb.name)

    for kb_name in to_delete:
        obj.shape_key_remove(obj.data.shape_keys.key_blocks[kb_name])
    
    maxWeight = survey(obj)
    # fix bug pointed out by user2859
    ka = []
    ka.extend(maxWeight.keys())
    ka.sort(key=lambda gn: -gn)
    print (ka)
    for gn in ka:
        if maxWeight[gn]<=0:
            print ("delete %d"%gn)
            obj.vertex_groups.remove(obj.vertex_groups[gn]) # actually remove the group