title: Error in three.js :- Materials[json.type] is not a constructor
body: <p>I am working on a web app which will render 3D animated models. These models made by 'Maya 2016'. I am exporting these models using three.js (r81) 'maya exporter plugin' (You can check maya exporter plugin here).
  <a href="https://github.com/mrdoob/three.js/tree/dev/utils/exporters/maya" rel="nofollow">link</a>, When i am loading this exported json model using below code:</p>
  
  <pre><code>var objectLoader = new THREE.ObjectLoader(manager);
  objectLoader.load( 'assets/New-Heart/full_heart.json', function (object) {            
      scene.add(object);
  }, onProgress, onError );
  </code></pre>
  
  <p>Then it is giving following error: <strong>Uncaught TypeError: Materials[json.type] is not a constructor</strong> in three.js library file (<strong>var material = new Materials json.type ;</strong>) on line no : 31381</p>
  
  <p>Please help me to fix this issue. any suggestion would be appreciable.</p>