The Looper is actually a preset for the Interpolator available in the Automation panel to replace the Looper from the previous version of Duik.

Optical Toy, Phenakistiscope Disc with Cats and Donkey,
ca 1830
Public domain.

  1. Select the properties.
  2. Click the Looper button

All interpolations are deactivated to keep only the extrapolation, set to a Cycle loop foor the in and out extrapolation.

▷ Read the Animation / Tools / Interpolator for more information.