[Dan Ebberts]

Sorry, I’m completely lost. I wish I could help, but I still don’t understand what it is you’re trying to do. Maybe someone else will chime in with the solution.

[Dan Ebberts]

I don’t understand your formula. Why does having the checkbox on flip the effect of null1 and null2? It seems like it should just remove the effect of null2.

[Dan Ebberts]

Ah, OK. I don’t think you’ll ever be able to set it up so that the position doesn’t change instantly when you toggle the checkbox to bring the influence of Null 2 in or out. There’s no way for the expression to know the history of the checkbox (unless it’s keyframed or controlled by an expression).

[Dan Ebberts]

>as if it were a regular null.

I have to confess, that I have no idea what that means. Are you talking about parenting?

[Dan Ebberts]

If you want Null 1 to move based on the relative movement of the other nulls, the other nulls need reference points. One way to do it is to keyframe their movement and Null 1 can take on movement of the other nulls that has occurred since time = 0. That would look something like this:

n2 = thisComp.layer("Null 2");
n3 = thisComp.layer("Null 3");
n4 = thisComp.layer("Null 4");
includeN2 = effect("Checkbox Control")("Checkbox") == 1;
d2 = n2.position - n2.position.valueAtTime(0);
d3 = n3.position - n3.position.valueAtTime(0);
d4 = n4.position - n4.position.valueAtTime(0);
val = value + d3 + d4;
if (includeN2) val += d2;
val

Null 2’s movement only gets included if the checkbox is on. If you want to animate the checkbox, that’s a much more complicated proposition…

[Dan Ebberts]

In what way to the other nulls “influence” Null 1’s position? What does that mean, exactly?

[Dan Ebberts]

You could use an expression for Audio Levels where the amplitude falls off as the inverse square of the distance from the camera increases. You’d need to define a nominal distance where at that distance or closer the falloff is 0 db. Something like this:

nominalDist = 2800;
C = thisComp.layer("Camera 1");
T = thisComp.layer("Target");
d = length(C.position - T.position);
if (d > nominalDist){
  n = Math.log2(d/nominalDist);
  value - ((value instanceof Array) ? [n,n]*6 : n*6);
}else{
  value;
}

[Dan Ebberts]

Assuming you’re controlling the slider with keyframes, you probably need something like the linear keyframe integrator described here:

https://motionscript.com/articles/speed-control.html

motionscript.com

Expression Speed and Frequency Control

Dan Ebberts's resource for After Effects scripting and expressions

[Dan Ebberts]

From what I can decipher from your screen shots, you should be able to use something like this:

gap = 100;
L = thisComp.layer(index + 1);
r = L.sourceRectAtTime(time,false);
x = fromComp(L.toComp([r.left + r.width, r.top]))[0];
[x + gap, value[1]]

[Dan Ebberts]

If you’ve never developed a plugin, the first one will be a bit of work, just getting familiar with the SDK and the whole process. Not messing with the pixels makes it considerably simpler and would be something I’d consider if you plan on doing this often, where you need complex controls where the state of one control needs to enable/disable other controls. Personally, I try to get by with Pseudo Effects whenever possible and only rarely feel the need crank out a controls-only plugin.