• Adobe After Effects

  Creating dust with objects (words) hitting a ground

  Posted by Gschlueter on August 24, 2007 at 12:54 am

  Any help here greatly appreciated!
  I have words falling from the sky and hitting the “ground”– want “dust” to rise as if, well, a heavy object fell from the sky and hit dusty ground… it should rise and gradually dissipate. Any suggestions appreciated! THANKS!

  Mike Clasby replied 19 years, 1 month ago 3 Members · 3 Replies
• 3 Replies

• 

  Mike Clasby

  August 24, 2007 at 5:23 am

  I like this.

  Overview: CC Ball Action and Scatter on a Duplicate layer of your text, with an Scale expression for Impact shake if desired.

  Details:

  Make your text and animate it’s fall.
  Duplicate it (Ctrl D). Name it Dust.
  To Dust add CC Ball Action and Scatter

  CC Ball Action
  Scatter: Keyframe 0 at Impact… and 3 to 5 frames later make it 40.
  Grid Spacing: Zero

  Scatter
  Scatter Amount: 0 at Impact… 50 a few frames later
  Uncheck “Randomize Every Frame

  Tweak all these to taste.

  Now to Dust’s Position, add a keyframe 4 to 5 frames after Impact by checking the add keyframe box, then about a second or two later (however long you want the dust to settle, set a keyframe to drop the Dust layer completely below the original text layer.

  I then added a New Black Solid with a rectangular mask to make a floor for the dust, so that when it dropped below the text it disappears… settles out.

  If you want to add a little Jell-O to the original text upon Impact, add this expression to the original text layers Scale (Copy the expression, Alt Click the Scale Stopwatch, Paste):

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

  if (n == 0){
  value;
  }else{
  maxDev = 10; // max deviation in pixels
  spd = 40; //speed of oscillation
  decay = 4.0; //how fast it slows down

  t = time – marker.key(n).time ;
  y = scale[0] + maxDev*Math.sin(spd*t)/Math.exp(decay*t);
  x = scale[0];
  [x,y]

  }
  Now add a marker to the original text layer at the point of Impact, by pressing the * (asterisk) key on the Numeric keypad. The Marker triggers the Jell-O effect. Move the Text layers anchorPoint to the bottom center with the Pan Behind Tool, so the scaling looks right. The expression above is all on the text layers Y, so if you want a true Squish and Squash, change the lines 17,18 from:

  y = scale[0] + maxDev*Math.sin(spd*t)/Math.exp(decay*t);
  x = scale[0];

  to

  x = scale[0] + maxDev*Math.sin(spd*t)/Math.exp(decay*t);
  y = scale[0]*scale[1]/x;

  These are Dan Ebbert’s expressions. Thanks Dan.
• 

  David Bogie

  August 24, 2007 at 7:08 pm

  Interesting and I bow to anyone who can write Expressions in their sleep like this, Yikes.

  There are also some PUFF presets in several particle plugins and in Apple Motion. Might even be one in in AE visible via Bridge.

  But I’m still an old fashioned guy; I say, got out out shoot some heavily sidelit talcum or gypsum dust against a black curtain.

  bogiesan

  This is my standard sigfile so do not take it personally: “For crying out loud, read the freakin’ manual.”
• 

  Mike Clasby

  August 24, 2007 at 9:57 pm

  I just hack Dan and others expressions. Sort of the Dr Frankenstein of expressions world.

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