Open3Dで点群のAABBとOBBを可視化する

たまに必要になるものの、Cloud CompareやMesh labで簡単に値をゲットする方法がなさそうなのでメモ書き。
plyの部分は適当に読み替えてください。

import sys
import numpy as np
import open3d as o3d
import sys

ply = o3d.io.read_point_cloud("xxx.ply")
point_array = np.array(ply.points)

lines = [
   [0, 1],
   [0, 2],
   [0, 3],
   [1, 7],
   [1, 6],
   [2, 7],
   [2, 5],
   [3, 6],
   [3, 5],
   [4, 5],
   [4, 6],
   [4, 7],
]

aabb = ply.get_axis_aligned_bounding_box()
vta = np.asarray(aabb.get_box_points())
print("aabb\n", np.asarray(vta))

colors = [[1, 0, 0] for i in range(len(lines))]
line_set = o3d.geometry.LineSet(
   points=o3d.utility.Vector3dVector(vta),
   lines=o3d.utility.Vector2iVector(lines),
)
line_set.colors = o3d.utility.Vector3dVector(colors)

obb = ply.get_oriented_bounding_box()
vtobb = np.asarray(obb.get_box_points())
print("obb\n", np.asarray(vtobb))


colors_obb = [[0, 0, 1] for i in range(len(lines))]
line_set_obb = o3d.geometry.LineSet(
   points=o3d.utility.Vector3dVector(vtobb),
   lines=o3d.utility.Vector2iVector(lines),
)
line_set_obb.colors = o3d.utility.Vector3dVector(colors_obb)

# red = AABB line color
# blue = OBB line color
o3d.visualization.draw_geometries([ply, line_set, line_set_obb])