• Adobe After Effects Expressions

  If Then Statement Help

  Posted by Dan Seibert on October 14, 2009 at 3:30 am

  Hey everyone.

  I’m looking to make something where layers get closer to the middle of the comp, the closer to a virtual camera in z space. I’m looking an expression to do that. I’ve been playing with the if then statement, but I need a little help understanding how to make it do what I want. Thanks.

  -Dan Seibert

  Xinlai Ni replied 16 years, 7 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Xinlai Ni

  October 14, 2009 at 4:51 am

  You don’t need if statement to do this, the thing you need is this expression of the position of the layer:

  xyPos = toComp(thisLayer.position); // project this layer to comp plane
  distToCompCenter = length(xyPos – [thisComp.width / 2, thisComp.height / 2]; // how far this layer is to the comp center
  distToCameraZ = 10 * distTocompCenter; // how far this layer to the camera in Z direction is 10 times of how far it is to the comp center
  [thisLayer.position[0], thisLayer.position[1], thisComp.layer(“Camera”).position[2] + distToCameraZ] // modify this layer’s Z position relative to the camera.

  This is assuming camera is looking at the Z+ direction, if not, you may want to offset the layer along the “look at” direction of the camera.

  Xinlai Ni
  Software Engineer, Google Inc.

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