Scale expression start at specific time

[Dan Ebberts]

Like this, probably:

timeToStart = 4;
if (time >= timeToStart){
t = time – timeToStart;
k=16;
a=5;
b=20;
x=k*(1-Math.exp(-a*t)*Math.cos(b*t));
[x,x]
}else{
[0,0]
}

Dan

[James Ireland]

Excellent thank you Dan.

I managed to find another of your expressions that triggers on layer start, very useful.

[James Ireland]

Hello again. Another question if I may.

I’ve ended up using the following expression for scale bounce which as you can see starts the movement on the layer in point. How can I make this happen in reverse and with a time trigger? So going from a 100% scale object that ‘bounces’ to 0% at a set time (or layer end?)

Scale up on layer in…

k=100;
a=5;
b=25;
t = time – inPoint;
x=k*(1-Math.exp(-a*t)*Math.cos(b*t));
[x,x]

Scale up at set time…

timeToStart = 4;
if (time >= timeToStart){
t = time – timeToStart;
k=16;
a=5;
b=20;
x=k*(1-Math.exp(-a*t)*Math.cos(b*t));
[x,x]
}else{
[0,0]
}

Thanks in advance for the help…

[Dan Ebberts]

You can make the first expression run in reverse like this:

k=100;
a=5;
b=25;
t = outPoint – time;
x=k*(1-Math.exp(-a*t)*Math.cos(b*t));
[x,x]

Dan

[James Ireland]

Brilliant that’s great Dan. I did however need the scale expression to occur after the first scale in and I’m unsure how to join the 2 expression together.

So either with time in then time out or as a layer that scales in on layer start and out on layer end.

I need it to happen on several layers throughout the comp at different times. Basically objects bouncing in and around then out as other layers mask in from behind.

Again apologies for my complete lack or expression knowledge. I thought I would dip my toe into expressions on this project, it’s all very interesting, some amazing time savers out there. Paul Tuersley’s PSD to 3D is incredible!…and of course thanks for all your help so far.

J

[Dan Ebberts]

Try this:

k=100;
a=5;
b=25;
if ( time < (inPoint+outPoint)/2){ t = time - inPoint; }else{ t = outPoint - time; } x=k*(1-Math.exp(-a*t)*Math.cos(b*t)); [x,x] Dan

[James Ireland]

Excellent. Works a dream, thanks Dan.

[Edy Brown]

Hi,

Does anyone have an idea how to use this expression in and out? (actually it works for IN, but i don’t know how to re-use it to make scale up at the end…)

Thanks

startScale = 300; // percent of Scale at start

endScale = 100; // percent of Scale at end

scaleUpTime = 1; // time to scale up from inPoint in seconds

s = ease(time,inPoint,inPoint+scaleUpTime,startScale,endScale);

[s,s]

[Dan Ebberts]

If you want it to do both, it would be something like this:

startScale = 300; // percent of Scale at start
endScale = 100; // percent of Scale at end
scaleUpTime = 1; // time to scale up from inPoint in seconds
if (time < (inPoint+outPoint)/2)
s = ease(time,inPoint,inPoint+scaleUpTime,startScale,endScale)
else
s = ease(time,outPoint-scaleUpTime,outPoint,endScale,startScale);
[s,s]

Dan

[Edy Brown]

Thank you Dan!
That works perfectly.

I am following creative cow for many years now, and found there most of the solution to the issues i got, (and it is the first time that i am taking part in a forum, what a shame!).
Thanks you for all.

Edgar