• Adobe After Effects Expressions

  Auto-orient without Auto-Orient Along Path

  Posted by Lord Scales on June 24, 2007 at 7:35 pm

  Hi there! I have noticed Auto-Orient Along Path does not changes the rotation value of the layer, and sometimes I miss it. So, to fix this, i created this expression for the rotation of a 2D Layer:

  var t = position.valueAtTime (time + thisComp.frameDuration); vec = position – t;

  radiansToDegrees (Math.atan2 (vec[1], vec[0]))

  The problem is that it only works when the layer is moving. I used a lot of if/else trying to correct but I just wasted time. So I need some help to solve this problem.

  Thanks!

  Dan Ebberts replied 18 years, 10 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Dan Ebberts

  June 24, 2007 at 8:05 pm

  If you want to calculate the world rotation of a 2D auto oriented layer (“Layer 1”), you can do it this way:

  L = this_comp.layer(“Layer 1”);
  V = L.toWorldVec([1,0]);
  radiansToDegrees(Math.atan2(V[1],V[0]));

  Dan
• 

  Lord Scales

  June 24, 2007 at 9:13 pm

  That’s perfect!
  Just one thing:
  toWorldVec([1, 0])
  means that only X axis will be converted?
• 

  Dan Ebberts

  June 24, 2007 at 9:29 pm

  Yes. Converting the x axis gives you everything you need to calculate the rotation.

  Dan

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