title: How do I despawn a rendered model in SceneForm?
body: <p>I am new to SceneForm. I have created a code that renders a model when user taps on a point on screen. How do I remove this model on say, when user taps a clear all button. 
  Here is my spawn function</p>
  
  <pre><code> private void addModeltoScene(ModelRenderable modelRenderable) {
  
  
      TransformableNode transformableNode = new TransformableNode(arFragment.getTransformationSystem());
      transformableNode.setParent(anchorNode);
      transformableNode.setRenderable(modelRenderable);
      //now add to scene
      arFragment.getArSceneView().getScene().addChild(anchorNode);
      transformableNode.select();
  
  
  
  }
  </code></pre>