title: Python Scipy get sides of a 3D convex hull
body: <p>I used <code>Scipy Delaunay</code> to compute the 3D convex hull of a set of points, and I'd like to get <strong>a list of all its external sides</strong> (triangles defined by 3 points), anybody knows how to get that information?
  Thanks</p>
  
  <p>code:</p>
  
  <pre><code>import scipy.spatial
  import numpy as np
  import csv
  """loading colors"""
  
  colors = np.array([(XYZRGB(rank, name, X, Y, Z))
                    for rank, name, X, Y, Z in csv.reader(open('colorshort.csv'))])
  
  """doing geometry"""
  
  tri = scipy.spatial.Delaunay(colors[:,[2,3,4]], furthest_site=False)
  # Delaunay triangulation
  indices = tri.simplices
  # indices of vertices
  vertices = colors[indices]
  # the vertices for each tetrahedron
  </code></pre>