JAVASCRIPT

javaScript Bezier Curve After Effects expression

N1 = thisComp.layer("Null 1");
N2 = thisComp.layer("Null 2");
N3 = thisComp.layer("Null 3");
N4 = thisComp.layer("Null 4");

p0 = N1.position;
p1 = N2.toWorld(N2.anchorPoint);
p2 = N3.toWorld(N3.anchorPoint);
p3 = N4.position;

c = 3*(p1 - p0);
b = 3*(p2 - p1) - c;
a = p3 - p0 - c - b;

t = index/(thisComp.numLayers - 3);
((a*t +b )*t + c)*t + p0