• Adobe After Effects Expressions

  Starting an Expression at a Specific Time

  Posted by George Costakis on April 5, 2009 at 1:10 am

  Hi All,
  So I’m trying to get an expression to start at a specific time, but I’ve not been able to get it to work. Here is the one I’m trying to do:

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

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

  It’s a pendulum motion that I’m applying to the X axis on a layer. Should I maybe be using a different expression for this that would allow me to stop and start it ? Thanks.
  -George Costakis

  Dan Ebberts replied 17 years, 4 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Dan Ebberts

  April 5, 2009 at 7:33 am

  Something like this, probably:

  timeToStart = 4; // start at 4 seconds

  if (time < timeToStart){ deltaX = 0; }else{ t = time - timeToStart; veloc = 7; amplitude = 80; decay = .7; deltaX = amplitude*Math.sin(veloc*t)/Math.exp(decay*t); } value + [deltaX,0] Dan

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