title: threeJS, OBJ's color not show up
body: <p>I have loaded the .obj file and set the color to its details, but it only shows up all black</p>
  <pre><code>const loader = new OBJLoader();
  loader.load( src, function ( obj ) {
    obj.traverse( function ( child ) {
      child.material.color.setHex(0xFF0000);
      console.log(&quot;child.material.color: &quot;, child.material.color);
    }
  }
  
  scene.add(obj);
  
  ...
  
  var hemiLight = new THREE.HemisphereLight( 0xffffff, 0x444444 );
  hemiLight.position.set( 0, 300, 0 );
  scene.add( hemiLight );
  
  var dirLight = new THREE.DirectionalLight( 0xffffff );
  dirLight.position.set( 75, 300, -75 );
  scene.add( dirLight );
  </code></pre>
  <p>the console.log print out the object Color: {r: 1, g: 0, b: 0, isColor: true}</p>
  <p>So, is there anything I have missed?</p>