This paper presents a new interaction system designed for hands-on 3D shape modeling and deformation through natural hand gestures. Our system is made of a Phantom haptic device coupled with a deformable foam ball that supports pressure sensors. These sensors detect forces exerted by the user's fingertips, and are used to control the configuration of a compliant virtual hand that is modeling soft virtual clay. During interaction, the user is provided both passive tactile feedback through the foam ball, and realistic visual feedback since the virtual hand deforms due to its interaction in the virtual environment. The combination of all these feedbacks provides the artist with a good immersion allowing for effective sculpting in a virtual world.

Figure 1: Left, a conceptual sketch of the HandNavigator device; center and right, examples of hands-on interaction with rigid and deformable virtual environment. AbstractThis paper presents a novel interaction system, aimed at hands-on manipulation of digital models through natural hand gestures. Our system is composed of a new physical interaction device coupled with a simulated compliant virtual hand model. The physical interface consists of a SpaceNavigator, augmented with pressure sensors to detect directional forces applied by the user's fingertips. This information controls the position, orientation, and posture of the virtual hand in the same way that the SpaceNavigator uses measured forces to animate a virtual frame. In this manner, user control does not involve fatigue due to reaching gestures or holding a desired hand shape. During contact, the user has a realistic visual feedback in the form of plausible interactions between the virtual hand and its environment. Our device is well suited to any situation where hand gesture, contact, or manipulation tasks need to be performed in virtual. We demonstrate the device in several simple virtual worlds and evaluate it through a series of user studies.

Sketching is an intuitive way to explain spatial relationships between complex objects. The French community of Anatomists are used to teaching didactic lectures on a blackboard with their colored chalks. The increasing complexity of the sketches affords to the students an opportunity to work out a mental representation of anatomical structures in 3D. To help students perform this labored step, we present a new interactive blackboard which constructs plausible 3D models of branching vessels from a single sketch. We exploit the sketching conventions used in anatomical drawings to infer depth and curvature. We then model the set of branching vessels as a convolution surface generated by a graph of skeleton curves. Classic situations, focused on arteries, have been analyzed to manage vessels' curvatures, subdivisions and overlaps. Original sketches and 3D models are presented for each case. No specific training is required to use the interface. The anatomists have begun to embrace a new generation of 3D digital modeling applications as tools for anatomical teaching. We discuss the future use of this system as a step towards the interactive teaching of anatomy.