title: Clickable particles in three.js PointCloud
body: <p>I am visualizing 3d data points (which I read in via a csv-file) with the help of three.js. 
  I want to click on points in that PointCloud to show other measurement data for those specific points. 
  According to examples I found this is possible apparently but I don't get it working. 
  I have the following code (basically from those examples):</p>
  
  <pre><code>function onDocumentMouseMove(e) {       
      mouseVector.x = 2 * (e.clientX / containerWidth) - 1;
      mouseVector.y = 1 - 2 * (e.clientY / containerHeight);
      var vector = new THREE.Vector3(mouseVector.x, mouseVector.y, 0.5).unproject(camera);
      raycaster.ray.set(camera.position, vector.sub(camera.position).normalize());
      scene.updateMatrixWorld();
      intersects = raycaster.intersectObject(particles);
      console.log(intersects);
  }
  </code></pre>
  
  <p>But intersects always is an empty array no matter which point I move over. </p>
  
  <p>Regarding the particles Object I wrote the following:</p>
  
  <pre><code>geometry = new THREE.Geometry();        
  
  for (var i = 0; i &lt; howmany; i++) {
      var vector = new THREE.Vector3(data[i][0], data[i][2], data[i][1] );
      geometry.vertices.push(vector);
  }
  
  attributes = {
       size: { type: 'f', value: [] },
       customColor: { type: 'c', value: [] }
  };
  
  uniforms = {
      color: { type: "c", value: new THREE.Color( 0xFFFFFF ) },
      texture: { type: "t", value: THREE.ImageUtils.loadTexture( "js/threejs/examples/textures/sprites/disc.png" ) }
  };
  
  var shaderMaterial = new THREE.ShaderMaterial( {
      uniforms: uniforms,
      attributes: attributes,
      vertexShader: document.getElementById( 'vertexshader' ).textContent,
      fragmentShader: document.getElementById( 'fragmentshader' ).textContent,
      alphaTest: 0.9,
  } );
  
  particles = new THREE.PointCloud( geometry, shaderMaterial );
  
  for (var i = 0; i &lt; howmany; i++) {
      colors[i] = new THREE.Color(RainBowColor(data[i][3], 4));
      sizes[i] = PARTICLE_SIZE * 0.5;
  }
  scene.add(particles);
  </code></pre>
  
  <p>where all the the variables are initialized previously, PARTICLE_SIZE is 20 and particles are about 10.000 in number with values between (0,0,0) and (10000,10000,10000). For rotating and zooming I use THREE.OrbitControls.</p>
  
  <p>Does anyone see the mistake or is raycasting with particles not possible in this case?</p>
  
  <p>Many thanks,
  Mika.</p>