title: CALayer perspective reset
body: <p>I've got the following trouble.
  In my app i'm implementing flip-clock. I've got 3  CATransformLayers and can swipe them up-down and down-up. I always have two layers on top with indexes 1 at top and 0 at bottom and one layer down  with index 2. So, when i flip down-up, i quickly rotate layer 0 down and transform layer 2 up, so layer 0 could already be visible.</p>
  
  <p>i'm using the following code to do this :</p>
  
  <pre><code>    auto CATransform3D t3d = CATransform3DIdentity;
      t3d.m34 = 1.0/-500.0;
      layer2.sublayerTransform =  CATransform3DRotate(t3d,  -angle  , 1.0, 0.0, 0.0) ;
  </code></pre>
  
  <p>to flip layer at index 2 ( bottom layer ) up.
  After this, i immedeately do the following with the layer at index 0 :</p>
  
  <pre><code>    auto CATransform3D t3d = CATransform3DIdentity;
      t3d.m34 = 0.0; // for make sure m34 is zero - excess code
      layer0.sublayerTransform = CATransform3DRotate(t3d,  M_PI  , 1.0, 0.0, 0.0) ;
  </code></pre>
  
  <p>After all animation completed - of up-down direction - i rearrange transform sublayers to make this action more and more times :</p>
  
  <pre><code>               [container.layer insertSublayer:layer0 above:(CALayer*)[container.layer.sublayers  objectAtIndex:2]] ;
  </code></pre>
  
  <p>Container is flip-clock's holder base view. The problem is, that when i flip one time - zero layer falls down on the back view normally. After second flip - it's all right too. But after third flip - the layer, that was flipped the very first time ( former layer 2) falls in the back scene with perspective, not looking at the fact, that i reset transformation to m34 = 0.0. What can be the reason for this? 
  As always, any help would be appreciated. </p>