This property is used to define what key(s) open a door.
The MasterBit checkbox is not used by this property, only by Engine Features→KeySrc
RegionMask specifies more data on the lock. It works in a similar way as the lockpicks. Each character can be a ‘0’ (False) or ‘1’ (True), and can only be opened by a key with that character also set to ‘1’ (True). So, for example, ‘110’ will open doors with RegionMasks of ‘100’ or ‘10’ (so long as they have correct LockID), but not ‘1’, as the third character on the key’s RegionMask is ‘0’, or false. You do not have to add (nor can you) add zeros before the number.
The number entered into LockID is the type of lock this door has. A key must have the same LockID to open the door.
Property Name: KeyDst