title: Can't get collision or trigger to work with 2 2D objects
body: <p>I have 2 sprites, both with "Box Collider 2D" component attached. I put the same detection functions in scripts attached to both objects:</p>
  
  <pre><code>void OnTriggerEnter2D(Collider2D coll) {
      Debug.Log ("Something triggered with me!!!");
  }
  
  
  void OnCollisionEnter2D( Collision2D coll ) { 
      Debug.Log ("Something collided with me!!!");
  }
  </code></pre>
  
  <ul>
  <li>This is Unity 5.2.1f1</li>
  <li>I've tried both trigger checked and trigger unchecked. I would prefer to use trigger because I don't need the objects to physically affect each other. </li>
  <li>I've verified the spelling of the function names and parameters. I've also tried removing both parameters.</li>
  <li>There is NO 2D rigid body on either object (I don't need one, do I?)</li>
  <li>Movement is currently being handled by a Translate() in the Update() loop of the objects.</li>
  <li>I've verified using "Edit Collider" that there is a decent box around each. </li>
  <li>I've RTFM'ed and read through most of the issues everyone else has seen here but I can't see what I am missing. 
  I've placed all collidable objects on the same layer called "Character" and it appears in the 2D collision matrix in the project settings and is checked.</li>
  </ul>
  
  <p><a href="https://i.stack.imgur.com/gne08.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/gne08.png" alt="enter image description here"></a></p>
  
  <p>Any suggestions?</p>