title: How to enable collision in babylon.js mesh
body: <p>I've been making a game in <strong>Babylon.js</strong>. In my game, there is a place where I have put a height map, it shows up when I run the scene, but when I try walking on it (or just standing on it) I fall through. I have searched almost everywhere and I haven't been able to find out why. This is my code: </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
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  <pre class="snippet-code-js lang-js prettyprint-override"><code>var ground = BABYLON.Mesh.CreateGroundFromHeightMap("ground", "Assets/Heightmap.png", 1000, 1000, 100, 0, 100, scene, false);
  var groundMaterial = new BABYLON.StandardMaterial("ground", scene);
  groundMaterial.diffuseTexture = new BABYLON.Texture("Assets/Sand.png", scene);
  groundMaterial.diffuseTexture.uScale = 50.0;
  groundMaterial.diffuseTexture.vScale = 50.0;
  ground.position.y = -2.0;
  ground.material = groundMaterial;</code></pre>
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  <p>Then I run this:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var gravityVector = new BABYLON.Vector3(0,-9.81, 0);
  var physicsPlugin = new BABYLON.CannonJSPlugin();
  scene.enablePhysics(gravityVector, physicsPlugin);</code></pre>
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  <p>After all of that, I try to run a BABYLON.PhysicsImposter for the ground but it doesn't work. So far I have tried the BoxImposter, MeshImposter, and HeightMapImposter. None of them worked for me.</p>
  
  <p>I am eager to get an answer, thanks in advance.</p>