After Effects Loop Expressions Explained

In After Effects, loop expressions are used to create repetitive and cyclical animations. They allow you to seamlessly repeat or cycle through keyframes, creating continuous motion without the need for manual duplication. Here are explanations for some common loop expressions in After Effects:

1. Loop Out:
   • loopOut(type = "cycle", numKeyframes = 0) or simply loopOut()
   • This expression repeats the animation values from the last keyframe to the first keyframe. The type parameter specifies the type of loop (e.g., “cycle” for continuous cycling).
2. Loop In:
   • loopIn(type = "cycle", numKeyframes = 0) or simply loopIn()
   • Similar to loopOut, this expression repeats values but cycles from the first keyframe to the last keyframe.
3. PingPong Loop:
   • loopOut(type = "pingpong", numKeyframes = 0) or loopOut("pingpong")
   • This expression creates a ping-pong effect, smoothly transitioning between the last and first keyframes, then back again.
4. Loop Expression for Time Remapping:
   • loopOut(type = "cycle") for time remapping
   • When applied to time remapping property, this expression repeats the playback of a layer.
5. Infinite Loop:
   • value + (time - inPoint) * velocity
   • This expression creates a continuous, infinite loop by continually incrementing the value over time based on velocity.
6. Loop with Offset:
   • loopOut(type = "cycle", numKeyframes = 0).offset(duration)
   • This expression combines loopOut with an offset, allowing you to stagger the repetitions.

Example usage:

// LoopOut example 
loopOut(); 

// PingPong Loop example 
loopOut("pingpong"); 

// Infinite Loop example 
value + (time - inPoint) * velocity;

These loop expressions provide flexibility for creating various repetitive animations, and by adjusting parameters like type and numKeyframes, you can customize the behavior of the loop to suit your specific animation needs.