title: AR.js aframe object show also without pointing marker
body: <p>In my AR project I use arjs with aframe to make my gltf object visibe when I point with my phone camera on my hiro pattern:</p>
  <pre><code>&lt;script src=&quot;https://aframe.io/releases/1.0.4/aframe.min.js&quot;&gt;&lt;/script&gt;
  &lt;!-- include ar.js for A-Frame --&gt;
  &lt;script src=&quot;https://jeromeetienne.github.io/AR.js/aframe/build/aframe-ar.js&quot;&gt;&lt;/script&gt;
  &lt;script src=&quot;https://unpkg.com/aframe-orbit-controls@1.2.0/dist/aframe-orbit-controls.min.js&quot;&gt;&lt;/script&gt; 
  
  &lt;body style='margin : 0px; overflow: hidden;'&gt;
    &lt;a-scene embedded arjs&gt;
      &lt;!-- define your gltf asset --&gt;
      &lt;!--This is for add a text--&gt;
      &lt;!--&lt;a-text value=&quot;Hello, World!&quot;&gt;&lt;/a-text&gt;--&gt;
      &lt;!--This is for add an image--&gt;
      &lt;!--&lt;a-image src=&quot;another-image.png&quot;&gt;&lt;/a-image&gt;--&gt;
      &lt;a-assets&gt;
        &lt;a-asset-item id=&quot;tree&quot; src=&quot;models/gltf/manovella.gltf&quot;&gt;&lt;/a-asset-item&gt;
      &lt;/a-assets&gt;
      &lt;a-entity gltf-model=&quot;#tree&quot; position=&quot;0 0 0&quot; rotation=&quot;0 90 0&quot; scale=&quot;10 10 10&quot;&gt;&lt;/a-entity&gt;
  
      &lt;a-entity camera look-controls orbit-controls=&quot;target: 0 1.6 -0.5; minDistance: 0.5; maxDistance: 180; initialPosition: 0 5 15&quot;&gt;
        &lt;!-- define a camera which will move according to the marker position --&gt;
        &lt;a-marker-camera preset='hiro'&gt;&lt;/a-marker-camera&gt;
      &lt;/a-entity&gt;
    &lt;/a-scene&gt;
  &lt;/body&gt;
  </code></pre>
  <p>when I point to my marker all was done, the problem is then also when I start my app without pointing to any market the object appears and when I no longer see the marker in the frame, the object remains on the screen.
  How can I manage my gltf show/hide only related to my marker?</p>
  <p>So many thanks in advance</p>