title: Matplotlib -- mplot3d: triplot projected on z=0 axis in 3d plot?
body: <p>I'm trying to plot a function in two variables, piecewise defined on a set of known triangles, more or less like so:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  from mpl_toolkits.mplot3d import Axes3D
  import random
  
  def f( x, y):
    if x + y &lt; 1: return 0
    else: return 1
  
  x = [0, 1, 1, 0]
  y = [0, 0, 1, 1]
  tris = [[0, 1, 3], [1, 2,3]]
  
  fig = plt.figure()
  ax = fig.add_subplot( 121)
  ax.triplot( x, y, tris)
  
  xs = [random.random() for _ in range( 100)]
  ys = [random.random() for _ in range( 100)]
  zs = [f(xs[i], ys[i]) for i in range( 100)]
  ax2 = fig.add_subplot( 122, projection='3d')
  ax2.scatter( xs, ys, zs)
  plt.show()
  </code></pre>
  
  <p>Ideally, I'd combine both subplots into one by projecting the triangles onto the axis z=0. I know this is possible with other variants of 2d plots, but not with triplot. Is it possible to get what I want?</p>
  
  <p>PS. this is a heavily simplified version of the actual implementation I am using right now, therefore the random scattering might seem a bit weird.</p>