Haptic sculpting of dynamic surfaces

Conventional free-form surface design usually require tedious control-point manipulation and/or painstaking constraint specification 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 various haptic sculpting tools to expedite the direct manipulation of B-spline surfaces with haptic feedback and constraints. One significant contribution of this paper is that point, normal, and curvature constraints can be specified interactively and modified naturally using 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 controlling 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 manufacturing, haptic interface, interactive graphics, medical applications, and virtual environments.