• Adobe After Effects Expressions

  marker trigger 3d rotation

  Posted by Guillaume Charron on August 25, 2009 at 2:58 pm

  Hi,
  I was using this expression to animate in a text layer on the X rotation (3D):

  veloc = 7;
  amplitude = 80;
  decay = .7;

  amplitude*Math.sin(veloc*time)/Math.exp(decay*time)

  To make it start when I wanted, I had to precomp it (because it uses the time of the comp). So I found another expression to trigger the expression with a marker:

  if (marker.numKeys > 0 && time >= marker.key(1).time){
  t = time – marker.key(1).time;
  freq = 2.0; //oscillations per second
  amplitude = 90;
  decay = 1.5;

  rotCos = Math.abs(Math.cos(freq*t*2*Math.PI));
  x = amplitude*rotCos/Math.exp(decay*t);
  value – [x]
  }else{
  value
  }

  It works but it is not swinging in both directions. It bounced on the 0 value and swing back up.

  Can you help me make it swing correctly using a marker as a trigger?

  thanks.

  Guillaume Charron replied 16 years, 8 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Dan Ebberts

  August 25, 2009 at 6:35 pm

  Try this:

  if (marker.numKeys > 0 && time >= marker.key(1).time){
  veloc = 7;
  amplitude = 80;
  decay = .7;
  t = time – marker.key(1).time;
  amplitude*Math.sin(veloc*t)/Math.exp(decay*t)
  }else{
  value
  }

  Dan
• 

  Guillaume Charron

  August 25, 2009 at 8:34 pm

  I knew it was something like that. I tried to find it myself but it didn’t work. THANK YOU very much. 🙂

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