title: Irrlicht collision with an invisible mesh
body: <p>I'm writing a Final Fantasy-like game engine, with 2D backgrounds and 3D models with Irrlicht.
  To calculate collisions with the objects in the background I use a invisible mesh like this:</p>
  
  <p><img src="https://i.stack.imgur.com/wSaaa.png" alt="enter image description here"></p>
  
  <p>I have tried with this code but when the player reaches the edge of the mesh it falls down:</p>
  
  <pre><code>TriangleSelector sel = device.SceneManager.CreateTriangleSelector(Program.field.currentScene.walkmeshLoaded, null);
  CollisionResponseSceneNodeAnimator coll = device.SceneManager.CreateCollisionResponseAnimator(sel, playerNode);
  playerNode.AddAnimator(coll);
  coll.Drop();
  sel.Drop();
  </code></pre>