title: Create wireframe of model in threes.js GLTFloader
body: <p>I want to load a 3D model and create the wireframe in threejs. How may I achieve this effect? Thank you very much.</p>
  
  <p>This is the code I have for now, but it doesn't work.</p>
  
  <pre><code>var loader = new THREE.GLTFLoader();
  loader.load('name.gltf', function(geometry, materials) {
      var material = new THREE.MeshLambertMaterial();
      var mesh = new THREE.Mesh(geometry, material);
      group = new THREE.Object3D();
      group.add(mesh); 
      scene.add(group); 
  });
  </code></pre>