How do I get the bounding box of all objects in a scene

Question

I have a scene with objects organized hierarchically like this:

I would like to get the overall bounding box of the 00000_361.L3B EMPTY object - however, since this is an empty it has no dimensions, and its bounding box also has no dimensions.

I am thinking of recursing through the hierarchy like explained here but I wonder if there is a better/easier way to do that at the scene level.

Answer 1

Bounding box coords of all meshes in scene.

Pretty sure this has been answered before, but finding it is another matter.

Here is some numpy code I use to create a bounding box for all mesh objects in a scene

Basically, list coordinates of all bounding box coordinates of all mesh objects in the scene.

Use the minima / maxima of each axis produce an axis aligned bounding box encompassing all others.

import bpy
from mathutils import Vector
from bpy import context
import numpy as np
import itertools
multiply 3d coord list by matrix
def np_matmul_coords(coords, matrix, space=None):
    M = (space @ matrix @ space.inverted()
         if space else matrix).transposed()
    ones = np.ones((coords.shape[0], 1))
    coords4d = np.hstack((coords, ones))
return np.dot(coords4d, M)[:,:-1]
return coords4d[:,:-1]


get the global coordinates of all object bounding box corners
coords = np.vstack(
    tuple(np_matmul_coords(np.array(o.bound_box), o.matrix_world.copy())
         for o in

            context.scene.objects
            if o.type == 'MESH'
            )
        )
print("#" * 72)
bottom front left (all the mins)
bfl = coords.min(axis=0)
top back right
tbr = coords.max(axis=0)
G  = np.array((bfl, tbr)).T
bound box coords ie the 8 combinations of bfl tbr.
bbc = [i for i in itertools.product(*G)]
print(np.array(bbc))