Within the Leap Service Provider Script are three different modes which set the initial hand pose.
This setting determines what the Leap Motion controller is expecting to see when a users hands enter the field of view.
Selecting the most suitable mode will help to reduce the initialisation time for hand tracking and improve the overall experience for the user.
There are two slightly different modes designed for a VR perspective and another for desktop use, below is an description of each mode:
DesktopModeA: This mode assumes that your hands are parallel to the ground, palm down, as the camera is looking straight up. In this instance the camera is expecting to see palms as this is typically the position that hands are held in this situation.
HeadMountedA: This mode rotates that position 180 degrees so that the camera's point of view changes. The camera now expects to see backs of your hands.
HeadMountedB: This mode is a slight variation on HeadMountedA. The hand rotation also angles the hand downwards on another axis. The reason for this is that in VR you might have your hands up in front of your face or down away from you, which rotates the hand a bit in relation to the camera)
The difference between HeadMounted A/B is minimal and the software will quickly correct the hand orientation by itself in HeadMounted mode. The main consideration to make is if you will be using the Leap Motion Controller on a desktop or in a head mounted configuration.