title: Set size of matplotlib figure with 3d subplots
body: <p>I have a figure where I want to plot a 3d scatter and a normal plot in 2 subplots.
  I use this code</p>
  
  <pre><code>fig = plt.figure(1)
  ax = fig.add_subplot(211, projection='3d')
  ax2 = fig.add_subplot(212)
  </code></pre>
  
  <p>then I use ax and ax2 to plot my data in the right place. But The figure I get is too small, how can I make it bigger?, adding <code>figsize=(w, h)</code> to the first line doesn't have any effect and results in an error if I add it to the second or third line.:</p>
  
  <blockquote>
    <p>AttributeError: 'Axes3DSubplot' object has no attribute 'set_figsize'</p>
  </blockquote>