• Adobe After Effects Expressions

  Scale in relation to position in comp

  Posted by Chris Gosling on May 27, 2014 at 11:51 am

  I have found the following expression that adjusts the scale of a layer based on it’s x-position in a comp

  But what I need to do is base it’s x-position of a parent comp.

  Example:
  I have a comp containing a static timeline with icons. As the comp moves along the x-axis in a parent comp then the icons need to scale up and then down as they approach and pass the centre of the parent comp.

  I am pretty sure that I need to change the layer positioning space somehow but I am really confused in that regard.

  Any help would be appreciated.

  Chris

  offset = 100; //amount to scale up
min = 0; //distance in pixels from the center where the layer is at full scale
max = 300; //distance in pixels from the center where the layer is at 'normal' scale
c = [thisComp.width / 2, thisComp.height / 2]; //center of the composition
p = toComp(anchorPoint); //location of the current layer in the composition
d = Math.abs((p - c)[0]); //distance from the center along the x-axis
x = ease(d, min, max, offset, 0);
value + [x,x,0]

  Dan Ebberts replied 7 years, 3 months ago 3 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  May 27, 2014 at 4:51 pm

  Try this (change the name of the parent comp to match yours):

  offset = 100;
  min = 0
  max = 300;

  C = comp(“Parent Comp”);
  L = C.layer(thisComp.name);
  center = [C.width, C.height]/2;
  p = L.toComp(toComp(anchorPoint));
  d = Math.abs((p – center)[0]);
  x = ease(d, min, max, offset, 0);
  value + [x,x,0]

  Dan
• 

  Chris Gosling

  May 27, 2014 at 4:56 pm

  Thanx a million Dan – just the trick. Know I just have try and understand it 😉

  C
• 

  Alexandre Maye

  February 5, 2019 at 10:39 am

  Hi there,

  Great expression ! thanks a lot !
  How can I apply this method but not to the scale but to the opacity ?

  Thanks a lot ! 🙂
• 

  Dan Ebberts

  February 5, 2019 at 6:24 pm

  Try changing the last line to:

  value + x

  or maybe just:

  x

  (depending on how you want the opacity to respond)

  Dan

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