An AET file serves as a reusable After Effects template, intended for repeated use so you open it, save a new project, and customize that copy, while the template stores the construction plan of the animation including comps, timelines, layers, keyframes, effects, expressions, camera/light settings, render configurations, and all the folder/interpretation organization that holds the project together.
An AET typically doesn’t embed the raw media; instead it references external clips, graphics, and audio, which is why these templates are usually distributed as a ZIP with a Footage/assets directory and why After Effects may prompt for missing files if anything was renamed, and because AETs may rely on specific fonts or third-party plugins, opening one on a new computer can lead to font substitutions until the required items are added, while remembering that file extensions aren’t exclusive, so the safest way to confirm the correct app is checking “Opens with” or considering where the file originated.
If you are you looking for more info regarding AET file structure look into the web site. An AEP file is your ongoing After Effects project, while an AET is a reusable template, so in practice the difference lies in purpose: you open an AEP to continue that same project, but you open an AET to begin a new project instance so the original stays clean.
That’s why AET formats are commonly packaged in motion-graphics template sets like intros, lower-thirds, and slideshows: the AET remains the creator’s master, and for each new video you open it, Save As a new AEP, then swap in your own text, media, logos, and colors, and even though both formats store the same project components—comps, layers, keyframes, effects, expressions, cameras/lights, and settings—and both usually reference external files, the AET safeguards the layout while the AEP becomes the editable end-user project.
An AET file usually contains everything needed to preserve the structure and behavior of a motion-graphics setup but not the raw media itself, keeping all compositions with their resolution, frame rate, duration, nesting, plus the full timeline of layers—text, shapes, solids, adjustments, precomps, and footage placeholders—along with each layer’s properties like position, scale, rotation, opacity, masks, mattes, blending modes, and parenting, as well as animation data such as keyframes, easing, markers, and any expressions that automate motion.
The template also saves effects and their specific settings—color correction, blurs, glows, distortions, transitions—and any 3D layout using cameras, lights, and 3D properties, plus the project’s render/preview options and organizational details like bins, labels, interpretation settings, and proxies, yet it typically doesn’t embed real footage, audio, fonts, or plugins, which means opening it elsewhere can prompt missing-file or missing-effect notices until you relink or install the required resources.
