H Haptic Rendering—beyond Visual Computing High-fidelity Haptic Synthesis of Contact with Deformable Bodies 48

cially created tactile sensations. One important use of these displays is to recreate the experience caused by contact between a tool and an object. This capability can be useful in several applications, such as surgical simulators, because users experience an enhanced sense of realism when a haptic simulation is combined with a graphic simulation. Haptic displays require two essential subsystems: a haptic device, which typically has a handle connected to sensors and actuators, and a computational system that interfaces with the device. As shown in Figure 1, the haptic simulator’s function is to reproduce what is felt. Because the physics of light differs from the physics of mechanical interactions, we must recognize that although graphic and haptic simulations can share the encoding of certain properties, such as shape, they must differ in many other aspects, such as models, mathematical techniques, and implementation. One key difference is the need to synthesize a force vector for haptics, as opposed to an illumination field for graphics. If all the components of the simulator are sufficiently accurate, the system can generate a vivid experience of interacting with real objects. The process of computing and generating forces in response to the interaction with virtual objects is sometimes called haptic rendering. For many applications, high fidelity is important. This article proposes a definition for high-fidelity haptic synthesis in terms of four requirements: