• Adobe After Effects

  QUESTION: how to affect shape layer skew value based on the velocity & direction of position property

  Posted by John Gardner on April 11, 2017 at 2:33 pm

  Hi,

  Long-time lurker. I have looked around for a solution to this question but I have not found anything, hence this post.

  Anybody know of a good expression that will take the position property info of a shape layer and have those values affect its skew property values?
  Basically looking for a simple squash & stretch effect, but using the skew property. So when a shape layer moves from A to B, the skew value will increase so that it appears to stretch a little, then once at location B, the skew will resolve back to 0.

  I researched Dan’s scripts, but I only found his squash/stretch script for the scale property.

  Any advice would be appreciated!

  Thanks,
  John

  John Gardner replied 9 years, 1 month ago 2 Members · 3 Replies
• 3 Replies

• 

  John Cuevas

  April 12, 2017 at 1:39 pm

  You would want to use one of the ease expressions applied to the “Skew” property of Distort Transform effect. Something like this:

  myVel = transform.position.velocity[0];
linear(myVel,0,500, 0, -18)

  Here’s a simple little project I made demonstrating the technique.
  11234_skew.aep.zip

  Johnny Cuevas, Editor
  ThinkCK

  “I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
  —THOMAS EDISON on inventing the light bulb.
• 

  John Gardner

  April 12, 2017 at 3:55 pm

  Thanks, John!
• 

  John Gardner

  April 13, 2017 at 9:43 pm

  Hi John,

  In case you need additional reference… I hacked together this solution as well… My apologies for not providing credits, as I pulled info from many people, so its a bit like making Frankenstein…

  Anyway, I would like to figure out how to add in some anticipation to the Skew value, just before the 1st key frame, so the shape layer sort of flexes before it moves.

  Place the following expression at: Shape layer > Content > Transform > Skew

  freq = 5;
  decay = 5;
  p=transform.position;
  x=transform.position[0];
  n = 0;

  if (p.numKeys > 0){
  n =p.nearestKey(time).index;
  if (p.key(n).time > time) n–;
  }
  if (n > 0){
  t = time – p.key(n).time;
  amp = p.velocityAtTime(p.key(n).time – .001);
  w = freq*Math.PI*2;
  result = amp*(Math.sin(t*w)/Math.exp(decay*t)/w);
  x=result[0];
  }else
  n;

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