A hand gestural interaction system for handling a desktop haptic strip for shape rendering

This paper presents a hand gestural interaction system that is used to handle a Desktop Haptic Strip for Shape Rendering (DHSSR). The strip is a physical display of virtual curves intersecting 3D virtual objects, and aims at allowing designers to evaluate the quality of shapes during the conceptual design phase of new products. The DHSSR consists of a servo-actuated developable metallic strip, which reproduces cross-sectional curves of 3D virtual objects. In order to generate the virtual curve intersecting the virtual object it has been implemented a hand gestural interaction system, which allows moving the curve or the 3D object. Specifically, through an interaction approach based on a magnetic pinch the user can move the virtual strip until reaching the desired position. Instead, an interaction modality based on index finger recognition allows moving the 3D object while the virtual curve is floating in space. The virtual curve generated by the interaction is used for deforming the physical strip. The hand gestural interaction system has been implemented by using low cost and open technologies, and combines an engine for interactive 3D content generation (Unity 3D), a motion capture sensor (LeapMotion) and the Arduino Leonardo board. In particular, the user's hands are tracked by means of the Leap Motion sensor. The Unity 3D environment is used to virtually render the virtual objects (curve and shape) and the virtual avatar of the users' hands. The virtual environment is connected with the Arduino Leonardo board in order to control the six servo-actuators of the DHSSR. The paper also presents some studies performed to evaluate the performances of the DHSSR system and the usability of the hand gestural interaction modalities.