Goodness! Your so right, how could I had forgoten!
Well I did do that and I was able to make several layers work, howeverw I got an error.

Here’s my script
Vy0 = thisComp.layer(“Null 1”).effect(“y Velocity”)(“Slider”); //initial y velocity (pixels/second)
Vx0 = thisComp.layer(“Null 1”).effect(“x Velocity”)(“Slider”); // initial x velocity (pixels/second)
g = thisComp.layer(“Null 1”).effect(“Gravity”)(“Slider”); // gravity (pixels/second/second)
floor = thisComp.layer(“Null 1”).effect(“Floor”)(“Slider”);
e = thisComp.layer(“Null 1”).effect(“Elasticity”)(“Slider”); //elasticity
b = floor – position[1];
h = b + Vy0*Vy0/(2*g);
T = Vy0/g + Math.sqrt(2*h/g);
if ((time-inPoint) < T){
y = Vy0*(time-inPoint) – g*(time-inPoint)*(time-inPoint)/2 + b;
}else{
Vy = -(Vy0 – g*T);
while (true){
Vy *= e;
t = T;
T += 2*Vy/g;
if ((time-inPoint) < T){
t = (time-inPoint) – t;
y = Vy*t – g*t*t/2;
break;
}else if (T – t < thisComp.frameDuration){
y = 0;
break;
}
}
}
I have the expression working on layers and comps. It also isn’t applied to certain Layers or Comps. Any light for this error?
Cool very cool! I’m excited… Just cause