Sometimes when editing videos in After Effects, you will want to enclose part of your videos inside some custom shape and leave the rest invisible. However
Problem with mask selection - Adobe Community - 11127195
After Effects Basics #7 - How to Make Smooth Keyframes
COMPLETE Beginners Guide to MASKING (After Effects)
After Effects CS6 Tutorial - 56 - Mask Properties
How to Make Mask Path Transformations Smoother!
Maya Creative Help, Smooth Options
Solved: How to animate expanding circle mask from the cent
Create and customize shapes and masks in After Effects
After Effects Tutorial - Cool Masking Trick
How To FEATHER SHAPES in After Effects