Recent advances of markerless motion capture techniques make it possible for HCI practitioners to design freehand gestures in various domains.However,most research focus on designer-defined gesture sets,and not much work has been done so far to study the user-defined ones.This paper investigates the intuitive freehand gestures that users naturally perform for 3D object control from afar on a large display.We report on the user choices of gesture types,users’ mental model,and derive critical aspects for the design space for freehand gesture.