title: Aframe.js, shadow="receive: false", don't display occlusion map on the second uvset
body: <p><strong>Description:</strong></p>
  <ul>
  <li>A-Frame Version: 1.1.0</li>
  <li>Platform / Device: PC</li>
  </ul>
  <p>Hello,</p>
  <p>if a glb model have <code>shadow=&quot;receive: false&quot;</code>, Aframe don't display occlusion map on the second uvset. Work with <code>shadow=&quot;receive: true&quot;</code>.<br/>
  why? it's a bug?<br />
  I would like use occlusion map to bake my lightmap, so don't use realtime shadow for this model.<br/>
  edit : but I want keep my light for other models with realtime shadow, like character, just want some models don't receive light if I  use a occlusionmap/lightmap.</p>
  <p>How Can I do?</p>
  <p>Thanks</p>