Blenderでマルチレゾとか使ってて左右対称が崩れたときリカバリーするスクリプト デフォルトは向かって右側が実態でサフィックス'.R', '.L' アドオン版はこちら https://github.com/mio3io/Mio3Symmetry

recovery_symmetrize.py

import bpy

def select_vertices(obj, op):
    bpy.ops.mesh.select_all(action='DESELECT')
    bpy.ops.object.mode_set(mode='OBJECT')
    
    if op == '+X':
        for v in obj.data.vertices:
            if v.co.x <= 0:
                v.select = True
    else:
        for v in obj.data.vertices:
            if v.co.x >= 0:
                v.select = True

    bpy.ops.object.mode_set(mode='EDIT')


def mirror_weights(obj, t1_suffix, t2_suffix):
    vgroups = obj.vertex_groups
    name_pairs = [(name, name[:-len(t1_suffix)] + t2_suffix) for name in vgroups.keys() if name.endswith(t1_suffix)]

    for from_name, to_name in name_pairs:
        from_group = vgroups.get(from_name)
        to_group = vgroups.get(to_name)

        if from_group and to_group:
            bpy.ops.object.vertex_group_set_active(group=from_group.name)
            bpy.ops.object.vertex_group_mirror(use_topology=False)


def symmetrize(obj, op):
    bpy.context.object.active_shape_key_index = 0
    bpy.ops.object.mode_set(mode='EDIT')
    bpy.ops.mesh.select_all(action='SELECT')
    if op == '+X':
        bpy.ops.mesh.symmetrize(direction='POSITIVE_X')
    else:
        bpy.ops.mesh.symmetrize(direction='NEGATIVE_X')

active_obj = bpy.context.active_object

symmetrize(active_obj, '+X')
select_vertices(active_obj, '+X')
mirror_weights(active_obj, '.R', '.L')

# hidarigawa
#symmetrize(active_obj, '-X')
#select_vertices(active_obj, '-X')
#mirror_weights(active_obj, '.L', '.R')

bpy.ops.object.mode_set(mode='OBJECT')

py.mp4