• Adobe After Effects Expressions

  Inertial Bounce on y axis scale only

  Posted by Brad Pickford on October 14, 2011 at 12:33 am

  Hi Everyone,
  I was wondering if anyone can help. I am trying to scale an object up from 0 – 100% and have inertial bounce applied to it. The thing is I only want the bounce to effect the “y” axis. Can’t figure out how to get this done.
  Cheers

  a = .03; f = 4.0; d = 10.0;
n = 0;if (numKeys > 0){n = nearestKey(time).index;if (key(n).time > time){n--;}}if (n == 0){t = 0;}else{t = time - key(n).time;}if (n > 0){v = velocityAtTime(key(n).time - thisComp.frameDuration/10);amp = a;freq = f;decay = d;
value+ v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);}else{value;}

  Justin Alexander replied 14 years, 6 months ago 3 Members · 3 Replies
• 3 Replies

• 

  Dan Ebberts

  October 14, 2011 at 3:04 am

  I haven’t test this, but I think you would just need to change one line:

  value + [0,v[1]*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t)];

  Dan
• 

  Brad Pickford

  October 14, 2011 at 3:10 am

  As always Dan, Spot on. Thanks a million!
• 

  Justin Alexander

  October 20, 2011 at 10:27 pm

  Hi I have posted a question similar to this but as I am new it is awaiting moderation.

  Is there a way to get this to work without the need for keyframes?

  Would love to be able to apply this to dozens of layers and get it to start at the inPoint, also would be awesome to slightly change the variables with sliders to get a nice randomness about it.

  Would also love to have it do the same in reverse at the outPoint with a quick little ‘bounce’ and then out she goes.

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