アクティブオブジェクトのシェイプキーの影響下にある頂点を選択する

shape_key_vertices.py

import bpy
import numpy

obj = bpy.context.active_object
bpy.ops.object.mode_set(mode="OBJECT")

vlen = len(obj.data.vertices)
selected = numpy.zeros(vlen, dtype=bool)
obj.data.vertices.foreach_get("select", selected)
obj.data.polygons.foreach_set("select", numpy.zeros(len(obj.data.polygons), dtype=bool))
obj.data.edges.foreach_set("select", numpy.zeros(len(obj.data.edges), dtype=bool))

vco = numpy.empty((vlen, 3), dtype=numpy.float32)
obj.data.vertices.foreach_get("co", vco.ravel())

for key_block in obj.data.shape_keys.key_blocks:
    if key_block == key_block.relative_key:
        continue
    
    points = numpy.empty((vlen, 3), dtype=numpy.float32)
    key_block.points.foreach_get("co", points.ravel())
    
    selected[numpy.where(vco != points)[0]] = True

obj.data.vertices.foreach_set("select", selected)

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

追加選択にしない場合は9行目はコメントアウトする

# obj.data.vertices.foreach_get("select", selected)