ABSTRACT
Quasistatic deformation models have been well known in haptic forcefeedback rendering for at least a decade since their introduction by Cotin and others. They provide computationally efficient models of smalldeformation response that reach equilibrium at time scales faster than graphics rates or user interactions. In this chapter, we revisit [James and Pai 01] and show how global deformation of linear elastostatic objects can be solved efficiently using precomputed Green’s functions and fast low-rank updates based on Capacitance matrix algorithms. Capacitance matrices provide exact contact response models, allowing contact forces to be computed for haptics much faster than global deformation behavior. Vertex pressure masks are introduced to support the convenient abstraction of localized scale-specific point-like contact with an elastic and/or rigid surface approximated by a polyhedral mesh. Examples are presented for the CyberGloveTM and PHANTOMTM haptic interfaces. Updated timings are provided, exhibiting approximately an order-of-magnitude improvement over [James and Pai 01].
