• Adobe After Effects Expressions

  Only show an object when the camera is within 45 degrees of it?

  Posted by Unit_9 on September 15, 2007 at 12:44 am

  Hi all, 🙂

  I want to fade in a series of images when the camera is within 45 degrees of facing them. I’d also like it to fade-in the image the closer you are to facing them – so 45 degrees away or more would be 0% alpha and 0 degrees (directly facing the image) would be 100% alpha.

  Can anyone help me with this??

  Dan Ebberts replied 18 years, 8 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Dan Ebberts

  September 15, 2007 at 4:10 am

  This should do the trick:

  C = thisComp.activeCamera;
  v1 = toWorldVec([0,0,-1]);
  v2 = normalize(C.toWorld([0,0,0]) – toWorld(anchorPoint));
  angle = radiansToDegrees(Math.acos(dot(v1,v2)));
  linear(angle,0,45,100,0)

  Dan

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