JIHAD EL SANA

Conventional free-form surface design usually require tedious control-point manipulation and/or painstaking constraint specifica-tion via unnatural mouse-based interfaces. This paper presents a novel haptic approach for the direct manipulation of physics-based B-spline surfaces. Our method permits users to interactively sculpt virtual yet real material with a standard haptic device, and feel the physically realistic presence of virtual B-spline objects with force feedback throughout the design process. We aim to develop var-ious haptic sculpting tools to expedite the direct manipulation of B-spline surfaces with haptic feedback and constraints. One signif-icant contribution of this paper is that point, normal, and curvature constraints can be specified interactively and modified naturally us-ing forces. We propose and formulate a dual representation for B-spline surfaces in both physical and mathematical space. This mass-spring model is mathematically constrained by the B-spline surface throughout the sculpting session. The equations of motion control-ling the physical behavior of the B-spline surface are solved using a tractable numerical solver in real-time. The integration of haptics with traditional geometric modeling will increase the bandwidth of human-computer interaction, and thus shorten the time-consuming design cycle. We envision that this integrated approach promises a much greater potential in computer-integrated design and manufac-turing, haptic interface, interactive graphics, medical applications, and virtual environments.