User Guide Cancel

Using the Expressions editor

Search
After Effects

After Effects

Open app
  1. After Effects User Guide
  2. Beta releases
    1. Beta Program Overview
    2. After Effects Beta Home
  3. Getting started
    1. Get started with After Effects
    2. What's new in After Effects 
    3. Release Notes | After Effects
    4. After Effects system requirements
    5. Keyboard shortcuts in After Effects
    6. Supported File formats | After Effects
    7. Hardware recommendations
    8. After Effects for Apple silicon
    9. Planning and setup
  4. Workspaces
    1. General user interface items
    2. Get to know After Effects interface
    3. Workflows
    4. Workspaces, panels, and viewers
  5. Projects and compositions
    1. Projects
    2. Composition basics
    3. Precomposing, nesting, and pre-rendering
    4. View detailed performance information with the Composition Profiler
    5. CINEMA 4D Composition Renderer
  6. Importing footage
    1. Preparing and importing still images
    2. Importing from After Effects and Adobe Premiere Pro
    3. Importing and interpreting video and audio
    4. Preparing and importing 3D image files
    5. Importing and interpreting footage items
    6. Working with footage items
    7. Detect edit points using Scene Edit Detection
    8. XMP metadata
  7. Text and Graphics
    1. Text
      1. Formatting characters and the Character panel
      2. Text effects
      3. Creating and editing text layers
      4. Formatting paragraphs and the Paragraph panel
      5. Extruding text and shape layers
      6. Animating text
      7. Examples and resources for text animation
      8. Live Text Templates
    2. Motion Graphics
      1. Work with Motion Graphics templates in After Effects
      2. Use expressions to create drop-down lists in Motion Graphics templates
      3. Work with Essential Properties to create Motion Graphics templates
      4. Replace images and videos in Motion Graphics templates and Essential Properties
      5. Animate faster and easier using the Properties panel
  8. Drawing, Painting, and Paths
    1. Overview of shape layers, paths, and vector graphics
    2. Paint tools: Brush, Clone Stamp, and Eraser
    3. Taper shape strokes
    4. Shape attributes, paint operations, and path operations for shape layers
    5. Use Offset Paths shape effect to alter shapes
    6. Creating shapes
    7. Create masks
    8. Remove objects from your videos with the Content-Aware Fill panel
    9. Roto Brush and Refine Matte
  9. Layers, Markers, and Camera
    1. Selecting and arranging layers
    2. Blending modes and layer styles
    3. 3D layers
    4. Layer properties
    5. Creating layers
    6. Managing layers
    7. Layer markers and composition markers
    8. Cameras, lights, and points of interest
  10. Animation, Keyframes, Motion Tracking, and Keying
    1. Animation
      1. Animation basics
      2. Animating with Puppet tools
      3. Managing and animating shape paths and masks
      4. Animating Sketch and Capture shapes using After Effects
      5. Assorted animation tools
      6. Work with Data-driven animation
    2. Keyframe
      1. Keyframe interpolation
      2. Setting, selecting, and deleting keyframes
      3. Editing, moving, and copying keyframes
    3. Motion tracking
      1. Tracking and stabilizing motion
      2. Face Tracking
      3. Mask Tracking
      4. Mask Reference
      5. Speed
      6. Time-stretching and time-remapping
      7. Timecode and time display units
    4. Keying
      1. Keying
      2. Keying effects
  11. Transparency and Compositing
    1. Compositing and transparency overview and resources
    2. Alpha channels and masks
    3. Track Mattes and Traveling Mattes
  12. Adjusting color
    1. Color basics
    2. Color management
    3. Color Correction effects
    4. OpenColorIO and ACES color management
  13. Effects and Animation Presets
    1. Effects and animation presets overview
    2. Effect list
    3. Effect Manager
    4. Simulation effects
    5. Stylize effects
    6. Audio effects
    7. Distort effects
    8. Perspective effects
    9. Channel effects
    10. Generate effects
    11. Time effects
    12. Transition effects
    13. The Rolling Shutter Repair effect
    14. Blur and Sharpen effects
    15. 3D Channel effects
    16. Utility effects
    17. Matte effects
    18. Noise and Grain effects
    19. Detail-preserving Upscale effect
    20. Obsolete effects
  14. Expressions and Automation
    1. Expressions
      1. Expression basics
      2. Understanding the expression language
      3. Using expression controls
      4. Syntax differences between the JavaScript and Legacy ExtendScript expression engines
      5. Editing expressions
      6. Expression errors
      7. Using the Expressions editor
      8. Use expressions to edit and access text properties
      9. Expression language reference
      10. Expression examples
    2. Automation
      1. Automation
      2. Scripts
  15. Immersive video, VR, and 3D
    1. Construct VR environments in After Effects
    2. Apply immersive video effects
    3. Compositing tools for VR/360 videos
    4. Advanced 3D Renderer
    5. Import and add 3D models to your composition
    6. Import 3D models from Creative Cloud Libraries
    7. Image-Based Lighting
    8. Extract and animate lights and cameras from 3D models
    9. Tracking 3D camera movement
    10. Cast and accept shadows
    11. Embedded 3D model animations
    12. Shadow Catcher
    13. 3D depth data extraction
    14. Modify materials properties of a 3D layer
    15. Work in 3D Design Space
    16. 3D Transform Gizmos
    17. Do more with 3D animation
    18. Preview changes to 3D designs real time with the Mercury 3D engine
    19. Add responsive design to your graphics 
  16. Views and Previews
    1. Previewing
    2. Video preview with Mercury Transmit
    3. Modifying and using views
  17. Rendering and Exporting
    1. Basics of rendering and exporting
    2. H.264 Encoding in After Effects
    3. Export an After Effects project as an Adobe Premiere Pro project
    4. Converting movies
    5. Multi-frame rendering
    6. Automated rendering and network rendering
    7. Rendering and exporting still images and still-image sequences
    8. Using the GoPro CineForm codec in After Effects
  18. Working with other applications
    1. Dynamic Link and After Effects
    2. Working with After Effects and other applications
      1. Export After Effects project as Premiere Pro project
    3. Sync Settings in After Effects
    4. Creative Cloud Libraries in After Effects
    5. Plug-ins
    6. Cinema 4D and Cineware
  19. Collaboration: Frame.io, and Team Projects
    1. Collaboration in Premiere Pro and After Effects
    2. Frame.io
      1. Install and activate Frame.io
      2. Use Frame.io with Premiere Pro and After Effects
      3. Frequently asked questions
    3. Team Projects
      1. Get Started with Team Projects
      2. Create a Team Project
      3. Collaborate with Team Projects
  20. Memory, storage, performance
    1. Memory and storage
    2. How After Effects handles low memory issues while previewing    
    3. Improve performance
    4. Preferences
    5. GPU and GPU driver requirements for After Effects
  21. Knowledge Base
    1. Known issues
    2. Fixed issues
    3. Frequently asked questions
    4. After Effects and macOS Ventura
    5. How After Effects handles low memory issues while previewing

Use the different options in the expression editor to customize your expressions.

You can customize the code editor interface of the expression editor, including highlighting JavaScript syntax with custom colors, line numbers, code folding, and auto-complete. To customize these options, select After Effects > Settings > Scripting & Expressions.

Scripting and Expressions dialog
Scripting & Expressions pane in the Preferences dialog box.

Expression editor code interface

Customize syntax highlighting of JavaScript syntax and After Effects methods and properties

Customize syntax highlighting
Customize syntax highlighting

  • You can assign custom colors to different types of syntax, the background, and the text selection, as well as adjust the alpha ( opacity ) of the text selection. Select the dropper icon to select a color from the color wheel.
  • You can customize how the expression editor looks based on the different themes available. Select the Theme drop-down list and select from the themes. You may also save custom themes.

Edit preferences

Edit preferences
Edit preferences

You can control how the expression snippets and the text editor look in the UI. Use these preferences to edit font size, syntax highlighting, adjust indents, and so on.

Code Preview box

Code Preview box
Code Preview box

All changes to the syntax colors and other editor preferences can be previewed live in this code preview box.

Tip:

Use throw to debug expressions inline. This is useful when you want to see the code error within the expression editor field to save time and ensure efficient debugging.

Throw to debug expressions inline
Throw to debug expressions inline

Example 1: Display error in your code snippet

  1. Open a comp in After Effects that has expression snippets.

  2. In the Timeline panel, select a layer and use Alt+Click to display the expression in the Expression Editor field.

    Expression Editor field
    Expression Editor field

  3. Select the editor field to enter the edit mode.

    Click in the editor to enable editing in the Expression Editor
    Click in the editor to enable editing in the Expression Editor

  4. In this example, select MILE in the first line and change it to mile in lowercase. This triggers an error in the code, and After Effects displays an error message within the code snippet.

    Error message displayed in the code snippet
    Error message displayed in the code snippet

    After Effects also displays an error banner with details about the line number where the error occurs.

    Error banner
    Error banner

Example 2: Auto-suggestions based on the commonly used components

  1. In the same expression, change the layer name from mile to MILE.

  2. As you type, After Effects displays a drop-down list with a set of suggestions that After Effects pulls from the layer names of the project.

    Layer name auto-suggestions
    Layer name auto-suggestions

Composition names, layer names, footage names, and effect names are all pulled into the autoComplete and shown in the correct context with their respective comp(), layer(), footage(), and effect() methods. This allows you to keep your expression active while referencing items in the project. You don't need to scroll the timeline or open other panels to refer to properties or items using the pick whip.

More Expression resources

Now that you have understood some of the concepts behind expressions, come to the community for some real-life examples, and to share your work.

The AE Enhancers forum also provides many examples and much information about expressions, as well as scripts and animation presets.

 Adobe

Get help faster and easier

New user?

Quick links

View all your plans Manage your plans
View quick links
Hide quick links

Legal Notices    |    Online Privacy Policy