diff --git a/lib/mpl_toolkits/mplot3d/art3d.py b/lib/mpl_toolkits/mplot3d/art3d.py
index b175bc5fc901..34b616eac767 100644
--- a/lib/mpl_toolkits/mplot3d/art3d.py
+++ b/lib/mpl_toolkits/mplot3d/art3d.py
@@ -12,7 +12,7 @@
 import numpy as np
 
 from matplotlib import (
-    artist, colors as mcolors, lines, text as mtext, path as mpath)
+    artist, cbook, colors as mcolors, lines, text as mtext, path as mpath)
 from matplotlib.collections import (
     LineCollection, PolyCollection, PatchCollection, PathCollection)
 from matplotlib.colors import Normalize