🔧 Mastering After Effects Expressions with MATH! | Motion Design Tutorial + ThinkPad P16 Review

I love Blender…

…but did you know I also have a soft spot for After Effects? 🎬 It’s literally the only Adobe app I still use — and here’s why:

With just a little math, After Effects can do some seriously powerful automation to save you hours of animation time.

In this tutorial, you’ll learn how to:

✅ Use sin() and cos() expressions for looping motion
✅ Animate with the built-in time variable
✅ Build custom piston-style mechanics using trigonometry
✅ Replace constant values with expression controls for flexibility
✅ Understand and build your own lookAt-style rig with real math!

Even if math isn't your strong suit, don’t worry — I break it all down clearly (with a little humour and a lot of visuals). By the end, you’ll accidentally understand trigonometry. No stress, no fuss, just smooth, mathematical motion.

🖥 BONUS: I also got to test out the Lenovo ThinkPad P16 Gen 2 (Storm Grey, ooh la la), and it’s a beast for motion graphics and VFX work. Quick review included before the tutorial starts.

Speak soon

00:00 - Intro
00:13 - Welcome
01:13 - Lenovo ThinkPad p16 Quick review
06:53 - start of tutorial
09:23 - First Math Lesson - sin curves
12:52 - Creating your First Expression
14:03 - Using "time" as an animation value
16:28 - multiplying your expression result to make it bigger
17:52 - adding cosine maths to add an animating offset
18:42 - It's a circle!
19:17 - adding extra variables to control the radius size
20:02 - applying these maths to our piston arm
21:00 - adding a new variable to speed up time
21:36 - using our expression to help drive the motion of the piston head
22:47 - adding the positional "value" to our expression motion
23:27 - It's time to put on your big Math pants!
24:43 - the lookAt expression and why not to use it
25:07 - arctangent math explained - ish...
26:10 - Writing a pointing at expression that works all the time
26:36 - finding out target position
27:10 - finding the x and y offset between our target and our arm position
27:41 - Quick Maffs! - getting the inverse radian angle between our points
28:21 - converting our radians to degrees and adding it to our original rotation value
28:57 - offsetting our result to make it point correctly
30:04 - replacing the constant value of time, with your own values
30:19 - adding an expression control slider to your layer
30:36 - adding your slider into your expression with the expression whip
31:04 - replacing time with your new variable pointing at your slider
31:33 - By the way, you've been learning trigonometry, you fabulous dude!
32:19 - If I could turn back time...oh, I can now, well, all righty then...
33:18 - outro - thank the gods, coz that was sooo long!!

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Bye and stay safe.
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📌 Links & Resources:
🌐 Website: www.gen-vfx.com
🐦 X: @genoden

🎵 Music Credit:
"Kind of a Party" by Mini Vandals
Promoted by YouTube Audio Library

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