Adaptive mass-spring model for soft body simulation

Abstract

Traditional computer simulation uses only a mouse, keyboard, and monitor as the input and output devices. With the recent emergence of haptic techniques, which can give users kinetic and tactile feedback, the field of computer simulation is diversifying. In particular, the need for virtual-reality-based surgical simulation has become great, stimulating new research the practical virtual simulation of surgery. In this thesis, we present a framework for a hybrid model of simulation that can realistically simulate the behavior of the soft, pliable human body, along with haptic feedback from the user’s interaction with it. A soft body simulation algorithm, which we refer to as the adaptive mass-spring model algorithm, is the core technique of the framework we present. Our framework has both a behavior model and a haptic model to support both the deformation of an object and the haptic feedback. The behavior model uses the adaptive mass-spring algorithm to calculate the realistic deformation of a virtual object in real time. Since our purpose is to provide a virtual environment for simulated surgery, virtual organs should reflect the properties of their corresponding real organs. Each virtual organ should be based on volumetric data because each real organ contains other tissues or vessels. The traditional soft body simulation algorithm uses surface data to represent the virtual object because this data is simpler than volumetric data. Since volumetric data includes other information internal to the organ, there is great computational complexity in the volume-data-based algorithm, which presents an obstacle to the execution of soft body simulation in real time. Our framework uses the adaptive mass-spring algorithm to reduce this computational complexity. The adaptive algorithm is an efficient algorithm that distributes the resources of the framework to the various elements according to their individual amounts of energy. First, the virtual object is divided into...