[Dan Ebberts]

I suppose you could create a shape layer (with a single click of the pen tool) and link its path to the mask with an expression. You could then get the dimensions with sourceRectAtTime(), and even turn the eyeball off for the shape layer so it doesn’t show up in the comp.

[Dan Ebberts]

It looks like you pasted it in twice, but in any case, the expression looks for the most recent, previous keyframe, calculates the velocity coming into that keyframe, and uses that velocity to calculate a decaying sine wave oscillation that gets added to the current value. The oscillation gets get off abruptly after 1 second.

[Dan Ebberts]

Try replacing the first line with this:

stopFrame = timeToFrames(inPoint) + 100;

[Dan Ebberts]

Something like this maybe:

L = thisComp.layer("Null 1");
p = L.transform.position;
d = p.valueAtTime(time-inPoint) - p.valueAtTime(L.inPoint);
value + d

[Dan Ebberts]

a = sets a to a value

a == compares a to something, returning true if they’re the same

[Dan Ebberts]

It could, but that would require a UI for the script, which is a bit of work. Here’s how the basic functionality might look though:

function setKF(){
	var myComp = app.project.activeItem;
	if (! (myComp && (myComp instanceof CompItem))){
		alert("No comp active.");
		return;
	}
	var myProps = myComp.selectedProperties;
	if (myProps.length == 0){
		alert("No property selected.");
		return;
	}
	var myProp = null;
	for (var i = 0; i < myProps.length; i++){
		if (myProps[i].numKeys >= 2){
			myProp = myProps[i];
			break;
		}
	}
	if (myProp == null){
		alert ("No property with 2 or more keyframes selected.");
		return;
	}
	var tStart = myComp.workAreaStart;
	var tEnd = tStart + myComp.workAreaDuration;
	var myExpr = "t = linear(time," + tStart + "," + tEnd + ",key(1).time,key(numKeys).time);\rvalueAtTime(t)";
	myProp.expression = myExpr;	
}
setKF();

[Dan Ebberts]

Do you mean the work area? Expressions don’t have access to the work area start and end times. Scripting does, so you could do it with a script, but it wouldn’t adjust automatically when you change the work area.

[Dan Ebberts]

Try this:

Math.floor(timeToFrames(time-inPoint)/90) + 1

[Dan Ebberts]

Maybe:

p = thisComp.layer("Layer A").position;
c = thisComp.activeCamera.position;
v = normalize(p - c);
c + v*((value[2]-c[2])/v[2])

[Dan Ebberts]

Something like this maybe:

L = thisComp.layer("3D Layer");
upperLeft = L.toComp([0,0,0]);
lowerRight = L.toComp([L.width,L.height,0]);
w = lowerRight[0] - upperLeft[0];
h = lowerRight[1] - upperLeft[1];