[Dan Ebberts]

Your question is somewhat confusing, because first you say:

>I would like to make the Blur Amount slider on the Master Control layer the control for the Blur Radius which is located on the Square layer

But then you say:

>…and the necessary expression would be written to the Blur Amount slider on the Master Control layer.

So I’m not sure what you’re after. To be clear though, an expression can only affect the property hosting the expression, so if you want the expression to control the Blur Radius on the Square layer, that’s where the expression would have to be applied.

[Dan Ebberts]

In line 3, you’ve got conflicting quotes. Try it this way:

var myExpr = 'thisComp.layer("Master Null").effect("Drive")("Output 01")';

[Dan Ebberts]

When I took your your code, removed the print() statements, and made the changes I suggested, it worked for me (copied the markers). I’m not sure why it doesn’t work for you.

[Dan Ebberts]

This would be the basics:

var myComp = app.project.activeItem;
var myProps = myComp.selectedProperties;
var myExpr = "value";
for (var i = 0; i < myProps.length; i++){
	if (myProps[i].canSetExpression) myProps[i].expression = myExpr;
}

[Dan Ebberts]

<div>Try changing this section:</div>

    win.ui.button01.onClick = function(){
        print("button 01 pressed"); //debug
        layersInToCompMarkers();
	}    
    win.ui.button02.onClick = function(){
        print("button 02 pressed"); //debug
        layerMarkersToComp();
	}    

to this:

    win.ui.button01.onClick = layersInToCompMarkers;
    win.ui.button02.onClick = layerMarkersToComp;

[Dan Ebberts]

Try it like this:

x = thisComp.layer("text").effect("Slider Control")("Slider");
if (x<=30){effect("low")("Color")}
else if (x>30&&x<70){effect("middle")("Color")}
else{effect("high")("Color")}

[Dan Ebberts]

Assuming that the scale of the parent is animated (via keyframes or expression), something like this could work:

s = thisComp.layer("parent").scale;
s.valueAtTime(0) + (s - s.valueAtTime(0))*0.75;

[Dan Ebberts]

Unless I’m missing something, I think it would just be:

thisComp.layer("parent").scale*0.75

[Dan Ebberts]

This should help:

http://www.motionscript.com/articles/speed-control.html#wiggle

[Dan Ebberts]

Something like this should work:

(thisComp.layer("% P&L").effect("Slider Control")("Slider")+2).toFixed(2)