title: How to modify UV coordinates with three.js
body: <p>I want to modify a JSON model's unwrap (UV coordinates) during runtime in order to move the texture over the surface of the geometry. I found <code>faceVertexUvs</code> in the <a href="http://threejs.org/docs/#Reference/Core/Geometry" rel="nofollow noreferrer">Geometry class documentation</a>. It contains one array, which is correct. That array contains a lot of elements, which I assume to be the UV coordinates for each vertex. Example code:</p>
  
  <pre><code>var uvs = mesh.geometry.faceVertexUvs[0];
  console.log(uvs.length);
  </code></pre>
  
  <p>Gives me <code>4232</code> as output. So far so good. Now I would like to alter the <code>u</code> and <code>v</code> values, but the 4000+ elements of the array are strings (<code>"1"</code> through <code>"4234"</code>). I only found examples showing how to create an unwrap from scratch, in which case people push Vector2 data up into <code>faceVertexUvs</code>. So why am I not seeing Vector2 data in there?</p>