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Making Current Speed and Maximum Speed
Hello,
I’m very new to AE Expressions. I have two text layers one is currentSpeed and second one is maxSpeed. currentSpeed is always changing rangin from 0 to 135. I want the maxSpeed to check currentSpeed. If currentSpeed is higher, then change to higher value. Else, stay at it’s current value.
I tested a lot but it doesn’t work.
Can someone help me with this?
Tnx.
max = text.sourceText
crSpeed = thisComp.layer("speed").text.sourceText
if (crSpeed > max) {max = crSpeed} -
4 Replies
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>I’m very new to AE Expressions
That makes me wonder if you know that expressions have no memory (expression results can not be passed from one frame to the next). I’m guessing that you want one text layer to present the maximum value of the other, up to the current time, is that correct? If so, at each frame, your expression will have to examine the value at all previous frames to find the maximum. Since it will be doing more and more work at each successive frame, things can slow down if your comp is long. Here’s an expression that does what I’ve described:
max = 0;
fCur = timeToFrames(time);
fStart = timeToFrames(inPoint);
for (f = fStart; f <= fCur; f++){
t = framesToTime(f);
temp = parseFloat(thisComp.layer("speed").text.sourceText.valueAtTime(t));
max = Math.max(max,temp);
}
max
Dan
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Tnx. Yea I didn’t know expressions don’t have memory. And yes the comp got so much slower. The max time it can handle is about 3mins and the scene is not that complex at all.
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After Effects does not have persistent memory for expressions. The entire expression is evaluated on each frame without regard for previous or next frames.
You can do this but it requires that you not only check the current frame but every previous frame as well. Also I believe you need to force the string objects into numbers:
t = timeToFrames(time);
max = 0;
for(x = 0; x <= t; x++){
crSpeed = thisComp.layer("speed").text.sourceText.valueAtTime(framesToTime(x)) * 1;
if (crSpeed > max) max = crSpeed;
}
max;
Darby Edelen
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Dan’s solution is, of course, more elegant 🙂
Darby Edelen
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