This I'm guessing is just been broken with an update or have Adobe changed the way this works? I use this all the time and now it doesn't work anymore.
Same for everyone?
Select a layer, pick the Rectangle, Ellipse, or any of the other shape tools and double click the tool and you should get a mask.
If that does not work then reboot. If that does not fix the problem try deleting your preferences.
No problems on the latest two AE builds for me. What is your AE version, OS and workflow?
Already have an account? Login
Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
AdChoices