Moving an object in 2D is not the same as moving it in 3D. Having a third dimension in After Effects works to explore depths in space as well, but also for handling the body and volume of any element on a Composition to create engaging animations.
However, you don't necessarily need 3D objects to create 3D motion in After Effects. By following several steps, it is possible to make the software also apply these effects even to your 2D objects.
You should keep in mind the process will be much easier if you have the 2021 or more recent versions of the software, since it has three new tools that simplify 3D work, such as the Orbit Around Cursor, Pan Under Cursor, and the Dolly Towards Cursor Tool.
Open a New Composition and import the files you will use in your project. After dragging them from the Project Panel to the Timeline, hover over the layer you want to animate with 3D motion and edit its properties:
Once you have the list of your layer properties open, take a look at the 3D transformation options that appear thanks to the previous steps. These are the values related to the rotation of the x, y, and z axes within the 3D space.
To animate a basic 3D rotation, make sure you see a stopwatch next to each of your layer's properties. This button is essential because when you turn it on (and depending on the feature), it will help you perform an animation:
Note two dots have been created on the Timeline. They are called keyframes and serve to indicate to After Effects the start and end of an animation.
Repeat the previous steps with the properties related to the x, y, and z axes so that your object moves correctly in 3D space.
Learning the above principle is essential when manipulating 3D objects because you must apply it when adding each effect to this type of space. Understanding it will help you to create high-quality animations in After Effects.