multiple bezier\masks

[T.P.]

hey guys , ok another basic question , i am trying to roto a movement in nuke , so i did myself a simple excersize , so i went and built a couple of bezier\masks which reveal the image like add in AE
like i learned , did them in a new channel and gave it a name ok fine , now how can i build a couple that subtract them , how can u do a subtract bezier in nuke ? plz help :confused:

[Aruna]

Use a ChannelMerge node.

[Diogo Girondi]

Or if they are in a single pipe just change the color on the beziers you want to subtract to black. You can also select the existent alpha channel on the mask drop down to do basic combinations if you want to.

[Gentle Fury]

or you can just do a merge and change the operator to out to cut away at the channel (i always used outside nodes in shake)