After Effects: How to make 3D path I am trying to make a 3D path that will be used as motion path for a object as well as base for Trim Paths. 

In other words, I would like to create something like Nyan Cat. I am going to use a path to animate movement of a 'cat' and to use same path to animate 'rainbow' by using Trim Paths. A 'cat' must move through 3D space eventually. Not sure if I chosen right direction so I would appreciate any tips about best practices for that kind of tasks. 

However I would really love to learn how to create 3D paths to use them as trajectory for a camera, for example. 

What I tried:

To create a circle -> make it 3D ->change its orientation -> convert to Bezier Path-ctrl+c. And then if I try to paste the copied path into an object position it get inserted as a 2D path. I could create 3D motion path for a camera manually using a Pen tool, however I would like a path to be a right circle.

Sorry if my question seems to be stupid, I am a really new. Thank you in advance!
Create a path with the Pen Tool first, copy the property path under:


  Contents > Shape 1 > Path > Path


Create a NULL object and paste the value you just copied to its position property.

You now have a NULL that follows your 2D path.



To enable the Z-axis of the NULL position, toggle the 3D Layer setting.

Click on the NULL position property and then get into the Graph Editor, in the bottom bar click the icon Separate Dimensions, this way you now have the 3 axis as separate properties.



You can see the Z Position is set at 0 without keyframes, despite the other 2 axis, play now with the Z Position and add keyframes as wished to give a 3rd dimension to your previously created 2D path.