simple scale expression

[Dan Ebberts]

Something like this should work:

rampStart = 0;
rampEnd = 30;
startVal = [100,100];
maxVal = [105,105];

rampMid = rampStart + (rampEnd – rampStart)/2;
if (time < rampStart || time > rampEnd){
value
}else if (time < rampMid){ ease(time,rampStart,rampMid,startVal, maxVal) }else{ ease(time,rampMid,rampEnd,maxVal,startVal) } Dan

[Robert Mutchler]

Thanks Dan,

It didn’t work for whatever reason. I copy and pasted the formula just how you wrote it.

Robert Mutchler
Wave Action Video

[Dan Ebberts]

Did it generate an error, or did it just not do anything? Scaling from 100% to 105% and back over 30 seconds is going to be barely perceptible.

Dan

[Robert Mutchler]

no error but I guess I wrote my question wrong. I want the layer to scale back and fourth from 100-105 over time. say every 15 frames it bounces back and forth from 100-105. sorry about the confusion.

Robert Mutchler
Wave Action Video

[Dan Ebberts]

Something like this then, maybe:

period = 15;
maxVal = 105;
minVal = 100;

f = 1/(period*thisComp.frameDuration);
amp = (maxVal – minVal);
s = amp*(Math.sin(f*time*Math.PI*2 – Math.PI/2) + 1)/2;

value + [s,s]

Dan

[Robert Mutchler]

That work! I change the period to 30 from 15. It was a bit quick. One more question if it’s easy to answer. I got the first 3 lines of code but the rest is confusing. I’m not great at math so I don’t know if even breaking it down will help. Thanks again.

Robert Mutchler
Wave Action Video

[Dan Ebberts]

First I convert the period to a frequency to use with the sine wave. The rest is just setting the sin wave up to start at 0, oscillate between 0 and 5, and ride on top of the static value (presumably 100 in this case).

Dan

[Caleb Minear]

Hey! I found this and the first expression,
rampStart = 0;
rampEnd = 30;
startVal = [100,100];
maxVal = [105,105];

rampMid = rampStart + (rampEnd – rampStart)/2;
if (time < rampStart || time > rampEnd){
value
}else if (time < rampMid){
ease(time,rampStart,rampMid,startVal, maxVal)
}else{
ease(time,rampMid,rampEnd,maxVal,startVal)
}

Works for what I need, i just need to make it happen faster. How do I do this?

[Dan Ebberts]

Change rampEnd to something smaller?

Dan

[Caleb Minear]

Ok. Changed what I was doing but thanks for the help!