• Adobe After Effects Expressions

  3d objects undulating as if floating in the ocean

  Posted by Robert Paynter on May 6, 2010 at 6:46 pm

  I have 15+ “postcards” in a comp. I would like them to undulate up and down as well as rotate As if they were floating in the ocean on the same body of wavy water.

  Any help would be appreciated.

  I found this
  https://www.motionscript.com/expressions-lab-ae65/undulations.html
  but it doesn’t seem to take into account X,Y and Z

  Robert Paynter replied 16 years ago 2 Members · 3 Replies
• 3 Replies

• 

  Robert Paynter

  May 6, 2010 at 8:59 pm

  ok I think I got it. so I changed the position expression to move on the z and hooked up the values to sliders. I then used the roatation expression and hooked them up to the same sliders and added a damping slider.. it’s looking pretty good

  position:
  xAmp = thisComp.layer(“Null 10”).effect(“Amp”)(“Slider”); //height of undulations (pixels)
  xFreq = thisComp.layer(“Null 10”).effect(“Freq”)(“Slider”); //undulations per second
  xSpeed = thisComp.layer(“Null 10”).effect(“Speed”)(“Slider”); //speed of wave (pixels per second)

  wl = xSpeed/xFreq; //wavelength (pixels)
  phaseOffset = ((position[0]%wl)/wl)*2*Math.PI;
  z = xAmp*Math.sin(2*Math.PI*xFreq*time + phaseOffset);
  value + [0,1,z]

  rotation:
  xFreq = thisComp.layer(“Null 10”).effect(“Freq”)(“Slider”); //undulations per second
  xSpeed = thisComp.layer(“Null 10”).effect(“Speed”)(“Slider”); //speed of wave (pixels per second)
  damping = thisComp.layer(“Null 10”).effect(“Damp”)(“Slider”); //undulation damping factor

  wl = xSpeed/xFreq; //wavelength (pixels)
  phaseOffset = ((position[0]%wl)/wl)*2*Math.PI;
  theta = Math.atan(Math.cos(2*Math.PI*xFreq*time + phaseOffset));
  radiansToDegrees(theta)/damping;
• 

  Dan Ebberts

  May 6, 2010 at 10:23 pm

  I think I’d try the noise() function for this. If you have your layers laid out in x and y, this should give you the undulation in z and otation in x and y:

  // position

  xyCompress = 500;
  speedCompress = 1;
  amplitude = 50;
  x = value[0];
  y = value[1];
  z = amplitude*noise([x/xyCompress,y/xyCompress,time/speedCompress]);
  [x,y,z]

  // x rotation

  xyCompress = 500;
  speedCompress = 1;
  amplitude = 50;
  x = transform.position[0];
  y = transform.position[0];
  z0 = amplitude*noise([x/xyCompress,(y-.1)/xyCompress,time/speedCompress]);
  z1 = amplitude*noise([x/xyCompress,(y+.1)/xyCompress,time/speedCompress]);
  radiansToDegrees(Math.atan2(z0-z1,.2))

  // y rotation

  xyCompress = 500;
  speedCompress = 1;
  amplitude = 50;
  x = transform.position[0];
  y = transform.position[0];
  z0 = amplitude*noise([(x-.1)/xyCompress,y/xyCompress,time/speedCompress]);
  z1 = amplitude*noise([(x+.1)/xyCompress,y/xyCompress,time/speedCompress]);
  radiansToDegrees(Math.atan2(z1-z0,.2))

  You’ll want to adjust the first three parameters to suit your needs (actually you should probably tie them to controls).

  Dan
• 

  Robert Paynter

  May 12, 2010 at 7:58 pm

  I’ll give it a try
  Thanks Dan.

Reply to this Discussion! Login or Sign Up