title: Rendering multiple scenes, with only 1 using SSAO [Three.js]
body: <p>In my continued experimentation with Three.js, I've hit another wall that I can't seem to climb over.</p>
  
  <p>I'm trying to have a background scene (that has a floor in it) rendered below a foreground scene which has an SSAO post-process effect. The background scene should not have any post-processing applied.</p>
  
  <p>I've tried multiple approaches (using masks, etc) and I just can't seem to crack this. The main problem I'm seeing is that the background of the SSAO scene is non-transparent so the background scene isn't showing. I'm still not convinced that even if that transparency issue is solved that things will work as expected. </p>
  
  <p>This is how things should look without <code>SSAO</code> post-processing: <a href="http://jsfiddle.net/uJbPe/1/" rel="nofollow">http://jsfiddle.net/uJbPe/1/</a></p>
  
  <p>And this is how things currently look with the SSAO post-processing enabled: <a href="http://jsfiddle.net/7hfdC/6/" rel="nofollow">http://jsfiddle.net/7hfdC/6/</a></p>
  
  <p>Any idea what I'm doing wrong?</p>