• Adobe After Effects Expressions

  Animating the Beam Effect with Layer Marker

  Posted by Aharon Rabinowitz on October 30, 2008 at 8:22 pm

  Hi folks-

  How might I animate the Time property of the Beam effect to go from 0% to 100% over X amount of time, every time it saw a layer marker on a null object?

  Precomping as a video and Time remapping won’t work because the effects End Point needs to change many times over the course of the animation.

  Thanks.

  Aharon

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web

  Aharon Rabinowitz replied 17 years, 9 months ago 2 Members · 10 Replies
• 10 Replies

• 

  Dan Ebberts

  October 30, 2008 at 8:35 pm

  Like this:

  x = 1; // transition time (seconds)

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

  if (n > 0){
  t = time – marker.key(n).time;
  linear(t,0,x,0,100)
  }else{
  0
  }

  Dan
• 

  Aharon Rabinowitz

  October 30, 2008 at 8:45 pm

  Thanks Dan! Is there a way I can have it delay in time. I want 4 beams to fire in succession. So beam one starts and then the next one starts and then the next one.

  Is there a parameter I could add into this that would say delay playing the animation by X amount of time?

  Best,

  Aharon

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web
• 

  Dan Ebberts

  October 30, 2008 at 8:55 pm

  You could have a delay based on the layer index, like this:

  x = 1; // transition time (seconds)
  delay = .1;

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

  if (n > 0){
  t = time – marker.key(n).time – delay*(index-1);
  linear(t,0,x,0,100)
  }else{
  0
  }

  Dan
• 

  Aharon Rabinowitz

  October 30, 2008 at 9:03 pm

  Thanks. Trying this out, I see it’s looking for the marker on this layer. Can I put the marker on a null?

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web
• 

  Dan Ebberts

  October 30, 2008 at 9:11 pm

  x = 1; // transition time (seconds)
  delay = .1;
  N = thisComp.layer(“Null 1”);

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

  if (n > 0){
  t = time – N.marker.key(n).time – delay*(index-1);
  linear(t,0,x,0,100)
  }else{
  0
  }

  Dan
• 

  Aharon Rabinowitz

  October 30, 2008 at 9:15 pm

  Thanks!

  Ah… OK. I see. My keyframes are not actually doing anything. The expression animates the value entirely.

  Problem. At 100% some of the beam is still visible. My keyframes set it back to 0%. But now that doesn’t happen. Is there a way to make it “rewind” or rather to jump back to 0% right after it gets to 100%?

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web
• 

  Dan Ebberts

  October 30, 2008 at 9:25 pm

  x = 1; // transition time (seconds)
  delay = .1;
  N = thisComp.layer(“Null 1”);

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

  if (n > 0){
  t = time – N.marker.key(n).time – delay*(index-1);
  if (t <= x) linear(t,0,x,0,100) else 0 }else{ 0 } 🙂
• 

  Aharon Rabinowitz

  October 30, 2008 at 9:28 pm

  Getting there – thank you. Very much appreciated.

  However, now that I have 4 beams firing, if the marker comes before they have all finished firing, they all jump back to 0%. So even though it delays playing, it’s holding them at 0 until their time to fire comes. Is there a way around this?

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web
• 

  Dan Ebberts

  October 30, 2008 at 10:05 pm

  try this one:

  x = 1; // transition time (seconds)
  delay = .1;
  N = thisComp.layer(“Null 1”);

  myDelay = delay*(index-1);
  n = 0;
  if (N.marker.numKeys > 0){
  n = N.marker.nearestKey(time – myDelay).index;
  if (N.marker.key(n).time > time – myDelay){
  n–;
  }
  }

  if (n > 0){
  t = time – N.marker.key(n).time – myDelay;
  if (t <= x) linear(t,0,x,0,100) else 0 }else{ 0 } Dan
• 

  Aharon Rabinowitz

  October 30, 2008 at 10:26 pm

  Phenomenal. Thank you!

  Aharon Rabinowitz
  Email: arabinowitz (AT) yahoo (DOT) com
  All Bets Are Off Productions, Inc.
  Creative Cow After Effect Podcast
  Internet Killed the Video Star: A Guide to Creating Video for the Web

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