• Adobe After Effects Expressions

  how to get the opposite?

  Posted by Marten Kopp on March 25, 2009 at 2:59 pm

  Hi,

  I got a question. Propeply very simple but I just dont understand a thing. How do you get some layer property to get the opposite value of another? e.g:

  the scale of my solid is 100% and the 2nd solid is -100%. how do I get the scale of my 1st solid to get to -100% if I keyframe the other to 100%??

  Sounds easy. Sorry for my poor english but I hope you guys understand my question.

  cheers.

  Pedro De jesus replied 9 years, 11 months ago 4 Members · 12 Replies
• 12 Replies

• 

  Dan Ebberts

  March 25, 2009 at 4:07 pm

  Just apply a Scale expression like this to the 2nd solid:

  -thisComp.layer(“1st solid name”).transform.scale

  Dan
• 

  Marten Kopp

  March 25, 2009 at 4:57 pm

  Thnx for your reply. But that wasnt exactly what i ment.

  What I’d like to know is this:

  What expression is needed to let one layer shrink the size the other layer grow?
• 

  Dan Ebberts

  March 25, 2009 at 5:06 pm

  More like this then, maybe:

  s = thisComp.layer(“1st solid name”).transform.scale;
  [100-s[0],100-s[1]]

  Dan
• 

  Marten Kopp

  March 25, 2009 at 5:33 pm

  Hi dan,

  Thnx for the help. But it still doesnt do what Im looking for. Solid 2 scale’s along with Solid 1 but it needs to go the oposit direction, like this:

  s1 = 100
  s2 = 100

  s1 = 150
  s2 = 50

  s1 = 200
  s2 = 0

  etc..
• 

  Dan Ebberts

  March 25, 2009 at 5:42 pm

  Try this:

  s = 200 – thisComp.layer(“1st solid”).transform.scale[0];
  [s,s]

  Dan
• 

  Marten Kopp

  March 25, 2009 at 7:47 pm

  Thnx man. That worked out great!
• 

  Gustavo Saliola

  December 27, 2012 at 4:28 pm

  Hi Dan, i’m just looking for something similar, but in this case, with “y” position, to animate two eye lids in a bug, in opposite positions with an Expression Control.

  Thanks in advance.

  Gustavo.
• 

  Dan Ebberts

  December 27, 2012 at 4:56 pm

  Assuming you have a Slider Control on a layer named “controls”, it would look like this for the upper eyelid:

  s = thisComp.layer(“controls”).effect(“Slider Control”)(“Slider”);
  value – [0,s]

  and this for the lower:

  s = thisComp.layer(“controls”).effect(“Slider Control”)(“Slider”);
  value + [0,s]

  Dan
• 

  Gustavo Saliola

  December 27, 2012 at 5:33 pm

  Thanks Dan! You Math Monster!
• 

  Pedro De jesus

  June 7, 2016 at 8:47 pm

  Hey Dan,

  Is there a command name we can use in expressions to tell it to do the opposite of what the original layer its pick-whipped to? Meaning, if LAYER 1 is moving up, and I want LAYER 2 to do the direct opposite (go down at the same speed while being connected to LAYER 1 via an expression), what command name should I use for that?

  This is just one example, but essentially I’m looking to be able to apply the opposite/inverse expression command to many other situations. Thanks!

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