After Effects expressions

[Smurry1982]

Hi all,

I'm animating a blood pressure gauge in After Effects. I'm hoping to figure out what expression or process to use that will enable the needle to move in a ticking motion as it follows a broader circular trajectory from a center position. Any tips or videos are appreciated!

[Mylenium]

I'm not clear what you are asking. What would an expression do that a simple rotation animation couldn't? If there is anything specific that would necessitate an expression, you have to explain way better. Otherwise, and no offense, this sounds to me like you are severely lacking in understanding some basics. Perhaps read the online help and watch some tutorials?

Mylenium

[ShiveringCactus]

Sounds to me like you should add a Wiggle expression.  You can keyframe your needle for the animation, then hold ALT and click on the stopwatch and type:

wiggle(1,10

The 1 in the expression is the frequency.  After Effects will make a change to the existing value once per second (so you can change this number to whatever you want).  The 10 is the amplitude range.  After Effects will alter the current value by up to 10 degrees (in this case if you're using rotation.  With the expression running, AE will change the current value once per second by up to 10 degrees, then the next second alter it again.

I made a tutorial a little while back which explains how to use the wiggle expression with keyframes:

https://www.youtube.com/watch?v=SqVZcGEZVp4&

[Smurry1982]

Thank you ShiveringCactus, I believe wiggle is very close, though I want to control the ticking more precisely. I have the blood pressure needle rotating around a gauge, and when I want to add a ticking—this would be for a controlled heart beat rhythm. This video shows the subtle back and forth  I'm aiming to create: https://youtu.be/Gmic13mvsgo?t=156

Your help is much appreciated!

[ShiveringCactus · Accepted solution]

Ah right, so more of a bounce/overshoot.  Check out this tutorial from Dan Ebberts: https://www.motionscript.com/articles/bounce-and-overshoot.html 

[Smurry1982]

I couldn't find the right words for that, so your help is appreciated! Have a great weekend.