• Adobe After Effects Expressions

  Random Characters with Multiple Lines

  Posted by Michael James on April 30, 2017 at 9:18 pm

  I’m trying to add a source text expression to a multi-line text layer where it’ll change every character randomly (limited to A-Z, 0-9) at a specific speed. For instance, if the text layer has two lines with 10 characters each, the expression would keep that exact format but change each character to a different random character, over and over again, at a specific speed.

  This expression sort of does what I need, however it doesn’t seem to dynamically preserve the original text format like number of characters and number of lines.

  c = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9'];
s = "";
for(x=0; x < value.length; x++){
r = Math.floor(random(0, c.length));
s += c[r];
}
s

  It also cycles through random characters every frame, which I’d like to control how often the characters change. (ie every 4 frames) How would I go about this expression?

  Thanks!
  -MJ

  Michael James replied 9 years, 4 months ago 2 Members · 4 Replies
• 4 Replies

• 

  Dan Ebberts

  April 30, 2017 at 10:40 pm

  This should work:

  
c = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9'];
s = "";
spl = value.split("\r");
for (i = 0; i < spl.length; i++){
for (j = 0; j < spl[i].length; j++){
r = Math.floor(random(0, c.length));
s += c[r];
}
if (i != spl.length-1) s += "\r";
}
s


  Dan
• 

  Michael James

  April 30, 2017 at 10:56 pm

  Hey Dan,

  Thanks! This works almost perfectly. Is there a variable I can add to the expression to customize the speed in which the characters change? Right now they cycle once every frame. Would there a variable to change the cycle to once every 4 frames or once every 2 frames?

  -MJ
• 

  Dan Ebberts

  April 30, 2017 at 11:08 pm

  Try this:

  
c = ['A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','0','1','2','3','4','5','6','7','8','9'];
framesPerChange = 4;
seed = Math.floor(timeToFrames(time)/framesPerChange);
seedRandom(seed,true);
s = "";
spl = value.split("\r");
for (i = 0; i < spl.length; i++){
for (j = 0; j < spl[i].length; j++){
r = Math.floor(random(0, c.length));
s += c[r];
}
if (i != spl.length-1) s += "\r";
}
s


  Dan
• 

  Michael James

  April 30, 2017 at 11:11 pm

  Works perfectly! Thank you so much for your help! Really appreciate it.

  -MJ

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