• Adobe After Effects Expressions

  Video clips flip onto the screen

  Posted by Joe Smoe on July 21, 2010 at 2:44 am

  I was wondering if there is an expression I could use to get the Fifth effect on the video on this site.
  https://finalcutprotemplates.com/templates/

  I basically want my video clip to flip onto the screen, and I know after effects can easily do this. I hope there could be an expression of some sort to solve this.

  Basically I’m hoping to flip a videoclip onto the screen by having it rotate on it’s X axis. I could easily do that with keyframes, but there must be an expression out there that give it more variables that I can even think of to make it more lively.

  Thanks.

  Chris Wright replied 16 years ago 2 Members · 1 Reply
• 1 Reply

• 

  Chris Wright

  July 21, 2010 at 7:24 pm

  I can think of 2 ways off the top of my head.

  you can use Math.exp() to generate exponential curves. Say you have a slider (“Slider Control 2” in this example) with two keyframes, then you could calculate an exponential curve between the two values with something like this:

  slider = effect(“Slider Control 2”)(“Slider”) ;
  decay = 5.0;
  if (slider.numKeys < 2){
  slider.value
  }else{
  t = slider.key(1).time;
  v1 = slider.key(1).value;
  v2 = slider.key(2).value;
  if (time < t){
  slider.valueAtTime(time);
  }else{
  v2 + (v1-v2)/Math.exp(decay*(time-t));
  }
  }

  You would set the steepness of the curve with the variable “decay” (or tie it to a slider).

  //Or…
  //

  Inertial Bounce is like making your moves “rubbery.” Layers will overextend, then settle into place on position and rotation keyframes.

  // Inertial Bounce (moves settle into place after bouncing around a little)
  n = 0;
  if (numKeys > 0){
  n = nearestKey(time).index;
  if (key(n).time > time){
  n–;
  }
  }
  if (n == 0){
  t = 0;
  }else{
  t = time – key(n).time;
  }

  if (n > 0){
  v = velocityAtTime(key(n).time – thisComp.frameDuration/10);
  amp = .05;
  freq = 4.0;
  decay = 2.0;
  value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
  }else{
  value;
  }

  https://technicolorsoftware.hostzi.com/

Reply to this Discussion! Login or Sign Up