A user interface system includes one or more controllers configured to move freely in three dimensions, where the one or more controllers include an inertial sensor coupled to measure movement of the one or more controllers, and output movement data including information about the movement. The user interface system further includes a processor coupled to receive the movement data, where the processor includes logic that, when executed by the processor, causes the user interface system to perform operations, including receiving the movement data with the processor, identifying an unintentional movement in the movement data with the processor, and outputting unintentional movement data that identifies the unintentional movement.
