[Filip Vandueren]

Hmm. I’m stumped,

the expression is correct, but there’s an error in how After effects sometimes does the calculations inside of the expression selector. The sourceRectAtTime is definitely not changing randomly, you can visualize those values via another textlayer, and the numbers stay consistent.

I would perhaps do the calculations of the ratios once in a different textlayer, and get those values in the expression selector using split() or JSON.parse() of that result

[Filip Vandueren]

Yes, in the project settings make sure your JavaScript expressions engine is set to “JavaScript” and not to “legacy extendscript”

[Filip Vandueren]

Hey Detlef,

can you check if this way works out for you:

https://www.youtube.com/watch?v=b52jyEFPnYQ

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[Filip Vandueren]

Hey Tavo,

do you want to count how many layers are hitting the target at the same time ?

So if C1 and C3 would overlap in the square it would be resulting in 2 ?

Do you want the position to be very precise, or is it more of a collision check: when the squares touch, they count ?

[Filip Vandueren]

(Pseudo code)

On a textLayer, use an expression that starts with posterizeTime(0), and that ends with JSON.stringify(theArray);

You can now JSON.parse(arrayTextLayerSourceText) in a different expression to read in the array which only got calculated once.

There are workarounds to use actual global variables via properties of the $-object, (they will stay the same until you re-assign or restart the app) but it is unsupported and can be buggy.

[Filip Vandueren]

No, you would have to do the Math yourself, which with rounded shapes can become complex fast.

You could use a dotted stroke with 1 minuscule dash and a huge gap (or trim paths) to get exactly 1 dot, which can move around with the stroke’s or trim’s offset, and then do sourcRect or SampleImage voodoo to find the position of those pixels.

Depends on what you want to do with the pointOnPath result.

[Filip Vandueren]

Here is one way to do it:

rate = 5; //value in px/sec.
if (marker.numKeys){
	t = timeToFrames(time - marker.key(1).time);
	if (t>0){
		if (marker.numKeys>1) {
			// more than 1 marker, stop scrolling at marker 2
			value - [0,rate]*clamp(t,0,timeToFrames(marker.key(2).time - marker.key(1).time));
		} else {
			// keep scrolling
		value - [0,rate*t];
		}
	}else{
		value;
	}
}else{
	value - [0,rate*timeToFrames(time-inPoint)];
}

[Filip Vandueren]

Could you share your project ? If I replicate what you describe I get the correct results.

[Filip Vandueren]

It should never go down, unless there are negative values in your slider ?

[Filip Vandueren]

Maybe your after effects is set up with legacy extendscript as the JavaScript engine ?

Remove the “const” keyword and it should be fine