Area-Contact Haptic Simulation Sang-Youn Kim 1 , Jinah Park 2 , Dong-Soo Kwon 1 1 Teloperation & Control Laboratory, Dept. of Mechanical Engineering, KAIST, Guseong-Dong 373-1, Yuseung-gu, Daejeon, 305-701, Korea {sykim@robot, kwonds@mail }.kaist.ac.kr 2 Computer Graphics & Visualization Laboratory, School of Engineering, ICU, Hwaam-Dong 58-4, Yugeong-gu, Daejeon,305-732,Korea jinah@icu.ac.kr Abstract. This paper presents the haptic interaction method when the interaction occurs at several points simultaneously. In many virtual training systems that interact with a virtual object, the haptic interface is modeled as a point. However, in the real world, the portion interacting with real material is not a point but rather multiple points, i.e., an area. In this paper, we address an area- based haptic rendering technique that enables the user to distinguish hard regions from softer ones by providing the distributed reflected force and the sensation of rotation at the boundary. We have used a shape retaining chain linked model that is suitable for real-time applications in order to develop a fast area-based volume haptic rendering method for volumetric objects. We experimented with homogeneous and non-homogeneous virtual objects consisting of 421,875 (75x75x75) volume elements. 1. Introduction In most virtual environments, a deformable object is modeled as a mesh, and the probe of the haptic interface is modeled as a point, which is known as the haptic interface point (HIP). Haptic rendering is a process that generates an interaction force between a virtual object and the haptic interface point [1,2,3]. Until now, most haptic rendering methods have focused on point-based haptic rendering. In point-based haptic rendering, since the probe of the haptic interface is modeled as a point, interaction forces can be calculated easily and quickly. One of the important factors in haptic rendering is to give a realistic feeling to the user as the user touches a real object. In most cases, when the user interacts with a real object (for example, in palpation) the interaction occurs at several points simultaneously, i.e., area contact. Consider the case when we touch an object with a finger. We have many touch sensors at the fingertip. By integrating the stimulating forces at those sensors, we may perceive the hard portion and soft portion of a non- homogeneous object, simultaneously. Consider that we construct the palpation simulator system. Since the stiffness coefficient of the hard portion is larger than that of the soft portion, the reflected force in the hard portion is larger than that of the soft portion. Therefore, we can also perceive the hard portion and soft portion of a non- homogeneous object by using a tactile display.