7 Replies Latest reply on Aug 28, 2014 10:06 PM by Audray_Black

# Orbit One Shape Around Another

Hello,

I'm rather new to After Effects, and what I'm trying to do is make a smaller circle orbit around a bigger circle, like a moon orbiting around a planet, without making either of the shapes 3D. I have looked everywhere, but the only method I can find is making both shapes 3D images, and I don't want that. Is there a way to do this?

• ###### 1. Re: Orbit One Shape Around Another

Two choices here. Parent the orbiting layer to the  center layer and animate the rotation of the center layer.

Second choice, use the anchor point tool to move the anchor point of the orbiting layer to the center of the center layer, then rotate the orbiting layer.

• ###### 2. Re: Orbit One Shape Around Another

My AE motto is, "If you don't HAVE to use 3D, use 2D"... but this is one of these instances where 3D is a lot easier than 2D.

The good news --  nothing says you have to maintain 3D throughout the project.  Precomp the big circle and the orbiting circle, and as long as you don't hit the 3D switch, the precomp is just another 2D layer.

• ###### 3. Re: Orbit One Shape Around Another

Thanks Rick, but it's not what I'm looking for. I'm looking to set the orbiting layer on a horizontal path, rotating in front of the center layer, and then going behind it as well.

• ###### 4. Re: Orbit One Shape Around Another

What Dave said...

To do this in 2D you need to animate the position and scale of the orbiting layer and then add a track matte of the stationary layer that varies in opacity as the layer moves behind the stationary layer. Something like this:

The key is the entrance and exit speed for the position property to make it seem like the orbit is somewhat elliptical.

Here's a CS6 version of the project for you to play with. When you have a bunch of repeating keyframes a simple loopOut("cycle") or loopOut("pingpong") expression will save you a lot of time. The timing of the keyframes is also critical.

• ###### 5. Re: Orbit One Shape Around Another

I figured it out, it was less complicated than I thought. I had to make the orbiting circle move once in front of the orbited circle, split the layer, move it back to its original position, and then move the last part of the animation behind the orbited circle to make it seem like it is moving in front and behind. Thank you guys for trying to help me I appreciate it.

• ###### 6. Re: Orbit One Shape Around Another

Did you take a look at the CS6 project I made for you?

• ###### 7. Re: Orbit One Shape Around Another

Yes I did, and let me tell you I was extremely impressed. I must have spent hours studying it and how it was done. You did a great job, thank you for making it. It helped me understand more of what I was trying to do, and I got a little experience with expressions.