blender_bounding_box.py

import bpy, bmesh
from mathutils import Vector

'''
Several problems solved:
  1) no need to activate or select the object
  2) no need to change origin after bpy.ops.object.transform_apply(location=True, rotation=True, scale=True)
  3) only 2 walls to check inside
'''
  
def meshBox(c1):
    bb = [c1.matrix_world * Vector(corner) for corner in c1.bound_box]
    mesh = bpy.data.meshes.new( "bb1_mesh_" + c1.name )
    clone = bpy.data.objects.new("BB_" + c1.name, mesh)
    clone.data.from_pydata( bb, [[0,1], [1,2], [2,3], [3,0], [4,5], [5,6], [6,7], [7,4], [4,0], [5,1],[6,2], [7,3]], [[0,1,2,3], [4,5,6,7]])
    scene = bpy.context.scene
    scene.objects.link(clone)
    scene.update()
    
  
meshBox( bpy.data.objects['object_name'] )