• Adobe After Effects Expressions

  Combinig expressions with keyframes

  Posted by Yair Neumann on January 23, 2009 at 1:48 pm

  I have a question that’s been puzzling me, how can I combine keyframes with expressions?
  Basically what I need is to make a photo’s opacity wiggle, but I only want this to begin at at a certain frame in the composition.
  Any help would be much obliged

  Filip Vandueren replied 17 years, 3 months ago 4 Members · 3 Replies
• 3 Replies

• 

  Paul Hennell

  January 23, 2009 at 3:26 pm

  Might be other better ways to do this but I’ve used this in the past –

  [Add Checkbox expression control]

  if (effect("Checkbox Control")("Checkbox") == 1){
  wiggle(10,100);
  }else{
  100
  }

  —
  Only in after effects do children get to pick and whip their parents.
  https://hennell-online.co.uk
• 

  Chris Arnold

  January 23, 2009 at 3:41 pm

  timeToStart = 2; 
    timeToStop = 4; 
      
    if ((time > timeToStart) && (time < timeToStop)){ 
        wiggle(3,25); 
    }else{ 
        value; 
    }

  Also, you can tell expressions when to start or stop via time or frame numbers.

  Here’s a link to adobe docs where they have info on how to stop and start a wiggle by just typing in the time you want it to stop and start. Same as code I placed in here.

  https://livedocs.adobe.com/en_US/AfterEffects/8.0/help.html?content=WS22BD9B45-A813-4b13-996D-A4561D108A8C.html
• 

  Filip Vandueren

  January 24, 2009 at 12:51 am

  In the case of Wiggle, you could also add a Slider Expression Control, and use that value as the wiggle amount.

  So you can keyframe from 0 (= no wiggle) to 100, instead of suddenly switching off the wiggle which will most likely cause the layer to jump from one position to another in 1 frame.

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