title: Three.js Child of camera isn't visible
body: <p>I'm trying to attach an object to the camera so that it can be used more more or less as a GUI element.</p>
  
  <p>My camera is defined as follows:</p>
  
  <pre><code>camera = new THREE.PerspectiveCamera( 45, windowWidth / windowHeight, 1, 2000 );
  camera.position.z = 100;
  </code></pre>
  
  <p>In my init(), I define the object to be added:</p>
  
  <pre><code>    obj = new THREE.Mesh(new THREE.CubeGeometry(5, 5, 5, 1, 1, 1),
  new THREE.MeshBasicMaterial({ color: 0xFFFFFF } ));
      obj.position.set( 0, 0, -50);
      camera.add(obj);
  </code></pre>
  
  <p>But, the block does not show up. I have tried adding this object to scene, and it is visible. I added a loop to animate() that will slide the object's z position between (-50, 50), but I can't see it.</p>
  
  <p>I tried using <code>camera.lookAt(obj)</code> and logging the world position of obj (obj position + camera position), and they behave as expected. World position seems to be what I'd expect, and camera.lookAt flips the camera when the z position crosses 0.</p>
  
  <p>I apologize for not providing more clear example code, but I will do my best to cooperate with anyone trying to help me. Thanks!</p>