Extras: Creating Cogs and Gears in AE
Extras: Creating Cogs and Gears in AE 5.5
CreativeCOW Adobe After Effects Tutorial

Creating cogs in After Effects (bought to you by the letter “V”)
Chris Zwar Chris Zwar
Entertainment Media
South Melbourne, AUSTRALIA

©2003 Chris Zwar and CreativeCOW.net. All rights reserved.

Article Focus:
This tutorial from Chris Zwar is a bit of a one trick pony, but it's a trick that's worth knowing. Cogs and gears are nice looking design elements and are popular in all sorts of backgrounds. If you do a search on the internet, it's easy to find a range of techniques for creating cogs in Photoshop and Illustrator, and Illustrator even comes with a few included. This is the "Extras" part -- If you haven't looked at parts 1-4, you probably should go back.

Download Movie Project files .sit Project files: .zip

While Part 4 of this series set the groundwork for our animated composition, there was a lot more to be done at the end of the tutorial.

The accompanying project file – Part 4 – Extras – shows how the project ended up. (Download the files from the green bar above.

Here are the main differences:

For a start, there are a lot more cogs. All of them are animated using expressions. Some of them have had their colour altered just to add some variety.

The two Drive Rods were pre-composed and have had textures added. If you do this, you will need to alter the expressions to match the name of your pre-compositions. The Drive Rods were also made thicker, but not longer.

The original “Drive Rod 1” expression featured the number “30”, to make the Drive Rod 30 pixels out from the centre of the cog. I added a “Slider” – which is an “expression controls” effect – and linked it to the expression, so we can change this value without altering the expression. Using the slider, we can move the Drive Rod in or out from the centre of the Cog. Note how the second Drive Rod and the round metal joint still appear in the correct position.

The Movement of the Drive Rods has been linked to a “steam” effect. The steam is just a simple Fractal Noise animation, but by linking the Opacity of the steam to the position of the Drive Rod, we can make it look like a piston is pushing out steam.

All of the cogs have had static axles added, by using a simple texture matte and using the “basic text” effect with bullet points to make the circles.

And using the “Bevel Alpha” and “Drop Shadow” commands, we can give our cogs depth.

The biggest and most dramatic change is in the speed of the animation. Originally, our Worm Gear turned once per second. But if we want we can play the Worm Gear movie faster, and because the entire composition is driven by expressions, we only have to change one number and all our animations will fit.

I looped the “Worm Gear” animation 240 times, and changed its speed to play 4 times faster, so it still runs for 1 minute.

The only thing I had to alter was our very first expression, which was originally “time*10” and is now “time*40”. Everything else still animates perfectly.

Hopefully you’ll have some fun playing around with this project, it’s really very easy to build up your own complicated gear boxes and drive trains.

---Finished here? Go back?---

In part one, we look at the basic concept behind making cogs in After Effects, using the Path Text effect. This will demonstrate our “trick” in detail.

In part two, we look at how we can extend this basic technique to produce more interesting looking cogs, using textures easily found on the internet.

In part three, we extend the same techniques to construct a worm gear.

And part four demonstrates how we can use simple expressions to create amazing animations using the parts we created in parts 1, 2 & 3.

Part 4 – Extras: From this basic overview, I created a more complete project with more cogs, and a few finishing touches. The project is called “Part 4 – Extras”, and although it isn’t a tutorial, there are a few notes about various refinements in it.

--- Chris Zwar

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