asdg>> technotes>> timeline masks and duplicateMovieClip()

Version: Flash 4+
Date Added: Feb 4, 2001
Last Updated: December 31, 2002

A timeline layer mask on a movie clip does not apply to any duplicates of the clip. To mask a duplicated clip with a timeline layer mask:
  1. Place the clip to be masked into a clip called container.
  2. Place container on stage.
  3. Apply the timeline layer mask to container.
  4. Duplicate the clip inside container as desired.
The mask will apply to any children of container, including those attached or duplicated at runtime.