Mask from Selection

Where to find them:

NodeGraph / Right Mouse Click / Edit /

Main Window / Extension Pack / Nodegraph / Edit

Shortcut (Nodegraph Only): ALT+M

Mask from Selection will generate a black and white mask from you current object, udim or face selection.

The Dialog that will open allows you to set the bitdepth and resolution of the mask that will be created, however the colors chosen there will have no effect on the created mask, which will always be black (not selected) and white (selected)