• Adobe After Effects Expressions

  Multiple layers randomly appearing

  Posted by Johan Tornlund on January 6, 2008 at 1:01 pm

  Hello! Here’s a problem I’ve been trying to solve for quite some time now.

  I am trying to create a matrix of layers that goes from 0-100% opacity from left to right.
  I think it’s difficult to describe this effect with simple words so I have manually keyframed the effect and rendered it out as a short example video.
  It happens very fast but if you go frame-by-frame you can see what kind of effect I’m trying to achieve.

  shapes video

  Basically I want the layers to “pop up” from left to right, but at the same time be influenced by a little bit of random delay.
  Is there an expression that would do this for me?

  Johan Tornlund replied 18 years, 4 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  January 6, 2008 at 8:54 pm

  If you have your layers sequenced (In Points set to where you want the layers to appear), this should work:

  rampTime = .5;
  ease(time,inPoint,inPoint + rampTime, 0, 100)

  If they all start at time zero, something like this should do it:

  sequenceTime = .4;
  rampTime = .5;
  beginTime = (index – 1)*sequenceTime;
  ease(time,beginTime,beginTime + rampTime, 0, 100)

  Adjust rampTime and sequenceTime as needed.

  Dan
• 

  Johan Tornlund

  January 7, 2008 at 12:11 am

  Dan, thank you for trying to help me with this.
  I realize now however that I forgot to mention a crucial part of my problem.
  What I really need is an expression that will duplicate a layer so I won’t have to do it manually.
  To be more precise, it is exactly what was mentioned in this thread:
  https://forums.creativecow.net/readpost/227/9041

  Your answer to that thead was that it isn’t possible unless one were to use the shape repeater. Luckily in my case all of the layers I want to duplicate are in fact shapes. The only problem left is to make them randomly appear across the screen.
  I can think of it as several shapes swooping by sideways that leave duplicates as a trail. And on top of that, each one of those shapes have a wiggle applied which affects their velocity.

  Wow that sounds really confusing, and I’m starting to question if the amount of work required is worth such a small effect. I might just resort to using your first expression instead, since it basically did the trick only without the random velocity. But either way, thank you for your time.

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