图4表达式：

freq = 6;

decay = 10;

n = 0;

if (numKeys > 0){

  n = nearestKey(time).index;

  if (key(n).time > time) n--;

}

if (n > 0){

  t = time - key(n).time;

  amp = velocityAtTime(key(n).time - .001);

  w = freq*Math.PI*2;

  value + amp*(Math.sin(t*w)/Math.exp(decay*t)/w);

}else

  value

图5表达式:

amp = .1;

freq = 2.0;

decay = 2.0;

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);

value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);

}

else{value}