• Adobe After Effects Expressions

  Typewriter forward then reverse

  Posted by Jonathan McAllister on October 22, 2022 at 10:16 pm

  Hi All,

  I have an expression which creates a typewriter effect from the “inPoint” of the layer which is perfect for my needs.

  What I am trying to do is reverse the effect so the text has reversed before the outPoint.

  I am usless at expressions and this one I have is butchered from one or two tutorials.

  I dont want to keyframe the layer as I am going to have quite a few of them and for workflow will be easier to shorten the layer length.

  Any help would be great.

  Here is my current expression:

  Speed = 20
  StartAt = inPoint

  X = text.sourceText;
  T = time * Speed - StartAt * Speed;

  if (T>0) X.substr(0,T)

  Jonathan McAllister replied 3 years, 10 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  October 22, 2022 at 11:42 pm

  Assuming you’re applying this to a text layer’s source text, I think this does what you want:

  Speed = 20;
  t = time < (inPoint+outPoint)/2 ? time - inPoint : outPoint - time;
  value.substr(0,t*Speed)
• 

  Jonathan McAllister

  October 24, 2022 at 1:16 am

  Thank you.

  I will give this a try.

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