title: Add vertices to an object that's being rendered
body: <p>Being new to three.js I've dived into editing lines and vertices to see what's possible. Right now I'm creating my own empty geometry (<code>vertObj</code>), and adding a few vertices to it initially.</p>
  
  <p>When it's rendered, I can see the vertices.</p>
  
  <p>I would like to keep adding vertices over time (via <code>vertObj.vertices.push</code>) and to make the modification possible in render loop, I've set</p>
  
  <pre><code>vertObj.dynamic = true;
  vertObj.verticesNeedUpdate = true;
  </code></pre>
  
  <p>however this does not change anything, I do not see the newly added points being rendered.</p>
  
  <p>Any ideas?</p>