Looping a Composition - After Effects

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This will loop your selected composition.

Looping a Composition

  1. Set your work area start and end points to the section of the composition you wish to loop. Then from the Menu bar, select Composition > Trim Composition to Work Area.
  2. Create a new composition (Command N) and keep your settings the same as the original composition. Then place the newly trimmed composition that you wish to loop (from the project panel) into your newly created composition by dragging it to the new composition panel (See note *).
  3. Now, in the new composition, go to the Menu bar and select Layer > Time > Enable Time Remapping. Time Remapping will create two key frames: one at the beginning of your composition and one at the end.
  4. Move to the very last key frame, step backwards one frame, and create a new keyframe.
  5. On the very last keyframe, double click on it and change the time to 0. Then double click on the last keyframe and delete it from your composition.
  6. Select the Time Remapping effect from the layer's composition panel to activate it, and from the Menu bar, select Animation > Add Expression.
  7. Time Remapping will now have an expressions box in the composition. Click on the Expressions Language menu icon in the composition panel; it will look like this: Expression icon ae.jpg, and then Property > LoopOut(Type="Cycle", numKeyframes = 0) will show up in the expressions box. Leave this as it is.
  8. Now you may extend the looping composition (by clicking and dragging it longer) and it will loop as many times as you want, repeatedly.
  • NOTE: This is different from pre-composing or nesting your compositions. For more information about what pre-composing or nesting does, click on this link: Precomposing/ Nesting Compositions. If you pre-compose when trying to loop, however, any effects or changes made to the pre-composition will not directly affect changes on the master composition. In other words, any looping changes made to the pre-composition won't be added to the master composition. This can cause problems if you are rotobrushing, for example.

Editing Master Composition

  • Now, if you want to add this looped composition back to your master composition, you can edit this together manually (as stated earlier, pre-composing won't do this automatically for you). To do this:
  1. Select the new composition that has your looped changes made to it.
  2. Then add a new layer to this composition by dragging the original master composition from the project panel to the composition panel.
  3. Select the new layer and move your playhead to the point where you want to break up the new layer (to add in the looped section). Then go to the Menu bar and select Edit > Split Layer (or press Shift, Command, D).
  4. Now you can move the layers around as needed to edit these changes back together.