• Adobe After Effects Expressions

  If (true) set value for next 4 frames

  Posted by Jeremy Wick on November 10, 2021 at 11:50 pm

  Is it possible to make an expression that, when triggered, changes the value for a set amount of frames? For example:

  if (statement == true) {

  // set opacity to 100 for next 4 frames, then 0

  } else {

  0

  }

  Andrei Popa replied 4 years, 6 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Andrei Popa

  November 12, 2021 at 6:45 am

  Hi Jeremy. Expressions can’t modify values in other places than the property on which they are applied, for the current frame. But for your case there is a workaround. You can evaluate the statement for the previous 3 frames, and if it’s true, make opacity 100. I imagine your statement checks the value of a property in the project, so you can use .valueAtTime() .

  Something like:

  durationCheck = 4;
  st = false;
  for(i = 0; i<durationCheck; i++){
  if( statement.valueAtTime(time-framesToTime(durationCheck)) == true ) st = true;
  }
  st == true ? 100 : 0;

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