• Adobe After Effects Expressions

  Link effects to marker on adjustment layer

  Posted by David Biederbeck on March 15, 2012 at 11:01 pm

  I downloaded a preset from I believe aaron rabinowitz called Film_Flash

  It creates a flash of light where there is a marker on the adjustment layer.

  How does this work? I am trying to create the same effect with twitch and hue/saturation

  Dan Ebberts replied 14 years, 4 months ago 2 Members · 1 Reply
• 1 Reply

• 

  Dan Ebberts

  March 15, 2012 at 11:56 pm

  There are a bunch of expressions that do different things to different properties, but they’re all driven by how long it has been since the most recent, previous marker. You get that with this code:

  
n = 0;
if (marker.numKeys > 0){
n = marker.nearestKey(time).index;
if (marker.key(n).time > time){
n--;
}
}


  When this code is finished, n has the index of the most recent previous marker (or 0 if no marker has been reached yet). Then you can do something like:

  t = time – marker.key(n);

  to calculate how long it has been since that marker and then use variable t in some calculation to generate the current value of the property hosting the expression.

  Dan

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