title: OnCollisionEnter not firing in Unity3D
body: <p>I know this has been asked many times but I have checked as many forums as I can. Here is everything I'm doing:</p>
  
  <p>I have a cube (that in this case is serving as the floor) with the following properties</p>
  
  <p><img src="https://i.stack.imgur.com/w7qLW.png" alt="Cube Properties"></p>
  
  <p>and I have a "Runner" that is just a cube with the following properties</p>
  
  <p><img src="https://i.stack.imgur.com/45ITw.png" alt="Runner Properties"></p>
  
  <p>I froze the z position and rotations because this is a side-scroller.</p>
  
  <p>The <code>onCollisionEnter</code> method for the "Runner" that you can see is attached to the "Runner" object is as follows:</p>
  
  <pre><code>    void onCollisionEnter(){
      print("Collision Detected");
  }
  </code></pre>
  
  <p>And when I run it, I get bupkis. So. Help please? It seems so simple but I am clearly messing something up.</p>