title: Three.js object3d.translateZ causes NaN in all position values
body: <p>It seems that when I use <code>translate[X|Y|Z]</code> on my object, its position gets mangled and only contains <code>NaN</code> values.</p>
  
  <p><img src="https://i.stack.imgur.com/HS826.png" alt="weird"></p>
  
  <p>Three.js r70</p>
  
  <p>The position is relative, the absolute is different:
  <img src="https://i.stack.imgur.com/eGBZL.png" alt="comparison"></p>
  
  <p>My code</p>
  
  <pre><code>if (!this.following) return false;
  
  var mesh = this.get(); //One mesh
  this.mesh.lookAt(this.mesh.worldToLocal((new THREE.Vector3(0, 0, 0)).setFromMatrixPosition(this.following.whom.matrixWorld))); //this.following.whom is another mesh
  
  var followerPosition = mesh.localToWorld(new THREE.Vector3(0, 0, 0));
  var followeePosition = this.following.whom.localToWorld(new THREE.Vector3(0, 0, 0));
  var distance = followerPosition.distanceTo(followeePosition);
  
  if (distance &gt; this.following.distance) { //this.following.distance is scalar value
      mesh.translateZ(distance * 0.02);
  }
  
  return true;
  </code></pre>
  
  <p>What am I doing wrong? Can I not use transformZ when dealing with relative values?</p>