[Dan Ebberts]

I don’t really understand what you’re trying to do with the random stuff, but this example might be helpful:

E = thisComp.layer("Effector");
radius = E("Contents")("Ellipse Path 1")("Size")[0]/2;
minFactor = .1;
f = thisComp.frameDuration;
p1 = E.position;
p2 = position;
tAccum = 0;
for (t = inPoint; t <= time; t += f){
  d = length(p1.valueAtTime(inPoint+tAccum),p2.valueAtTime(inPoint+tAccum));
  if (d < radius){
    factor = linear(d,0,radius,minFactor,1);
    tAccum += f*factor;
  }else{
    tAccum += f;
  }
}
position.valueAtTime(tAccum);

[Dan Ebberts]

Hmm… that looks like scripting. I thought you were asking about expressions.

[Dan Ebberts]

No way to do that, I’m afraid. If you can’t keyframe it, you can’t control it with an expression.

[Dan Ebberts]

Yes, so your idea of using a slider for all but the main dropdown is probably best.

[Dan Ebberts]

This might be overkill, but it might give you some ideas:

http://www.motionscript.com/design-guide/marker-sync.html

[Dan Ebberts]

Sorry, I posted in the wrong thread. I’ll be back…

[Dan Ebberts]

I’m not sure this is what you mean, but couldn’t you just apply an expression like this to the Menu properties in the subcomps:

comp("Main").layer("Controls").effect("Dropdown Menu Control")("Menu")

[Dan Ebberts]

To get you started, create a Shape Layer (Layer > New > Shape Layer). Add a Rectangle and a Fill.

Add this expression to the Rectangle’s Size property:

minWidth = 5;
maxWidth = 25;
seedRandom(index,true);
[random(minWidth,maxWidth),thisComp.height]

Add this expression to the Fill Color:

minVal = [.5,.5,.5,1];
maxVal = [1,1,1,1];
seedRandom(index,true);
random(minVal,maxVal)

Add this expression to the Layer’s Position:

minFreq = .25;
maxFreq = .75;
seedRandom(index,true);
freq = random(minFreq,maxFreq);
amp = thisComp.width/2;
w = wiggle(freq,amp);
[w[0],value[1]]

Add this expression to the Layer’s Opacity:

minVal = 25;
maxVal = 100;
seedRandom(index,true);
random(minVal,maxVal)

Duplicate the layer a bunch of times.

[Dan Ebberts]

Actually, this version should work from -41 to +41 degrees:

a = degreesToRadians(rotation);
offset = (value[0]/2)*Math.tan(a);
len = (thisComp.height/2)/Math.cos(a) + (a < 0 ? -offset : offset);
[value[0],len*2]

[Dan Ebberts]

I think I read the question wrong. I think it would be like this (and would only be good up to about 40 degrees):

a = degreesToRadians(rotation);
len = (thisComp.height/2)/Math.cos(a) + (value[0]/2)*Math.tan(a);
[value[0],len*2]