Exponential Functions in AE Expressions
by Roman Alvarado
on
Jun 30, 2008 at 1:00:32 pm
Hello. I am completely new to AE and recently began working with Expressions from scratch. I want a 2D object to scale from 10% to 100% over a modifiable length of time. However, I do not want the transformation to be linear and I don't want to create keyframes since this effect will later be triggered by another layer's properties.
begS=10;//initial and minimum scale
dK=.95//decay rate, must be < 1
xScale=begS+90-(90*(dK^time));// initial time + 90- a value that decreases with time from 90, never reaching 0.
yScale=xScale
[xScale,yScale]
I suspect it's a noob's syntax or language issue because the formula looks right in a graphing calculator. Basically, when I use this expression the animation jumps around and begins at 100% scale.
Anything to the 0 power is 1, so the scale value at time=0 should be: 10+90-(90*1)=10%.
At time=1, the scale should be: 10+90-(90*.95)=14.5%... and so on.
Thanks you for any help.
I searched the forums and found no explicit discussion about exponential notation within After Effects Expressions.
Re: Exponential Functions in AE Expressions by Roman Alvarado on Jun 30, 2008 at 7:26:30 pm
Ha! I knew it was a simple mistake. That's what I was looking for, thank you. I did manage to figure out a very roundabout solution to create a similar effect, but not as adjustable:
