title: How to get the mouse clicking position on an obj file loaded from OBJLoader?
body: <p>I loaded the model using OBJLoader, here is the code for loading the obj file:</p>
  
  <pre><code>        var loader = new THREE.OBJLoader();
          loader.load('obj/teeth/teeth4_5.obj', function(object) {
              model = object;
              scene.add( model );
              objects.push( model );
          });
  </code></pre>
  
  <p>And I'm trying to use raycaster to find the intersection. I implemented my code from the canvas_interactive_cubes example (<a href="http://mrdoob.github.io/three.js/examples/canvas_interactive_cubes.html" rel="noreferrer">http://mrdoob.github.io/three.js/examples/canvas_interactive_cubes.html</a>) in three.js. Here is the code to find the intersection:</p>
  
  <pre><code>    function onDocumentMouseDown( event ){
          event.preventDefault();
          var mouseX = (event.clientX / window.innerWidth)*2-1;
          var mouseY = -(event.clientY /window.innerHeight)*2+1;
          var vector = new THREE.Vector3( mouseX, mouseY, 0.5 );
          projector.unprojectVector( vector, camera );
          var raycaster = new THREE.Raycaster( camera.position, vector.sub( camera.position ).normalize() );
          var intersects = raycaster.intersectObjects( scene.children );
          console.log( intersects[0].point);
      }
  </code></pre>
  
  <p>Unfortunately I'm not able to get the x,y,z coordinates of the intersection, no matter where I clicked, it always showed "TypeError: intersects[0] is undefined".</p>
  
  <p>I'm getting stuck here for several days. Can someone tell me a way to get the intersection on a loaded obj file? I appreciate your help.</p>