Create a seamless repeat animation in After Effects

This simple After Effects CC animation needed to visualise the concept of sharing, so Iain Acton ran with the idea of a conga line of shapes moving between two tunnels. Here's how he did it…

01. Get started

Create a seamless repeat animation in After Effects - Get started — Iain uses a null to handle all the rotations in this animation

I began by creating two ellipses on shape layers with strokes. Next, I rotated the tunnels – I used a null to handle all the rotations in this animation. It takes nine seconds to do one complete cycle. Then I needed to parent those tunnels to the null.

02. Add a square

Create a seamless repeat animation in After Effects - Add a square — Iain animates the position property of the square to move it across the screen

Next I created a square on a shape layer, and animated the position property, moving it from one side of the screen to the other. I also needed this layer to rotate with the tunnels, so I parented that to the rotation null.

03. Orientation

Create a seamless repeat animation in After Effects - Orientation — Here's how to keep the shape's orientation

I wanted to keep the orientation of the shape throughout, so to do that I took the expression of the shape's rotation, turned it into a negative and then set it to rotate.

04. Matte effect

Create a seamless repeat animation in After Effects - Matte effect — Use a matte effect to make the shape look like it's emerging from the tunnel

I also wanted the shape to look as though it was coming out of one tunnel and into the other, rather than overlapping. To do this, I set a matte effect, and used a follow layer as the matte.

05. Make it loop

Create a seamless repeat animation in After Effects - Make it loop — Finally, make the whole thing loop and Bob's your uncle

I then duplicated that layer, changed the shape, changed the colour, offset all of these duplicates on the timeline, ensuring the first and last frames were exactly the same, and the animation looped perfectly.

This article originally appeared in Computer Arts issue 254; buy it now!