• Adobe After Effects Expressions

  simple position expression!

  Posted by Eric Braff on July 17, 2008 at 5:05 pm

  Hi..

  Thank you for having a look at this…
  what I am looking for is an expression like some flash sites can do. When you move something it seems to have its own velocity, like it might keep moving and slow down on its own..

  kind of like the bounce expression… how you can adjust the amp, freq, and decay…. but just for the position of lets say X!

  Well thank you so much, always grateful!

  Eric

  Eric Braff replied 17 years, 9 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  July 17, 2008 at 9:01 pm

  I’m not sure what you’re after exactly, but this expression will oscillate at the last keyframe. It won’t do anything unless you have at least two keyframes.

  n = numKeys;
  if (n >= 2){
  v = velocityAtTime(key(n).time – .001);
  freq = 1.0; //oscillations per second
  elasticity = .6;
  decay = 2.0;
  t = time – inPoint;
  value + v*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t)
  }else{
  value
  }

  You might have to play with the frequency, elasticity, and decay parameters.

  Dan
• 

  Eric Braff

  July 17, 2008 at 10:43 pm

  Thank you Mr. Ebberts!
  so grateful!

  e

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