Quick Start

Let's create your first composition with Compdown. By the end of this guide, you'll understand the basic structure and how to build animated layers.

Your first composition

Open the Compdown panel in After Effects and paste this:

compositions:
  - name: Hello World
    layers:
      - name: greeting
        type: text
        text: Hello World
        fontSize: 72
        transform:
          position: [960, 540]
      - name: background
        type: solid
        color: 1a1a2e

Click the Create button. Compdown will:

1. Create a composition named "Hello World" (1920x1080, 30fps, 10s — the defaults)
2. Add a text layer with "Hello World" centered in the frame
3. Add a dark solid layer called "background" behind it

That's it. You've created your first composition from text syntax.

Understanding the structure

A Compdown document has five optional top-level keys:

_timeline:  # Layers added to the active comp timeline (optional)
_selected:  # Actions for currently selected layers (optional)
folders:    # Project folders (optional)
files:      # Imported footage (optional)
compositions:  # Compositions with layers

At least one must be present. For most workflows, you'll use compositions, _timeline, or _selected.

Add layers to the active timeline

When you want to add layers to the currently active composition without creating a new comp:

_timeline:
  layers:
    - name: greeting
      type: text
      text: Hello World
      transform:
        position: [960, 540]
    - name: background
      type: solid
      color: 1a1a2e

Update or remove existing layers

Use explicit action words when you want to modify or delete:

_timeline:
  set:
    layers:
      - name: greeting
        transform:
          position: [960, 500]
  remove:
    layers:
      - name: background

For currently selected layers:

_selected:
  set:
    transform:
      opacity: 50
  remove: true

Composition properties

Compositions have sensible defaults:

Property	Default
width	1920
height	1080
duration	10 seconds
framerate	30 fps
color	000000 (black)

Override any of them:

compositions:
  - name: Square Comp
    width: 1080
    height: 1080
    duration: 5
    framerate: 60

Layer types

Each layer needs exactly one of:

• type: — Built-in types: solid, null, adjustment, text, camera, light, shape
• file: — Reference to an imported file
• composition: — Reference to another composition

layers:
  - name: my solid
    type: solid
    color: FF0000

  - name: my footage
    file: bg  # References a file with id: bg

  - name: nested comp
    composition: Lower Third  # References another composition by name

Adding animation

Transform properties can be static values or keyframe arrays:

layers:
  - name: animated box
    type: solid
    color: 3498db
    width: 200
    height: 200
    transform:
      position:
        - time: 0
          value: [200, 540]
        - time: 2
          value: [1720, 540]
      opacity:
        - time: 0
          value: 0
        - time: 1
          value: 100

This creates a blue box that:

• Moves from left to right over 2 seconds
• Fades in over 1 second

Keyframe syntax

Each keyframe needs time (in seconds) and value. Optionally add easing:

position:
  - time: 0
    value: [0, 0]
    easing: easeOut
  - time: 2
    value: [1920, 1080]
    easing: easeIn

Available easing types: linear (default), easeIn, easeOut, easeInOut, hold

Exporting compositions

Compdown works both ways. To export an existing composition:

1. Select a composition in After Effects
2. Click the Export button in Compdown
3. The composition appears as text syntax in the editor

This is useful for:

• Understanding what properties a comp has
• Creating a template from an existing design
• Version controlling your motion design

Next steps

You now know the basics. Explore further:

• Reference — Complete syntax documentation
• Examples — Real-world recipes and patterns