Block Manipulation with Hand in Virtual Space

1 . I n t r oduc t i on In recent years, high performance graphic work stations (GWS) have been developed which can generate high quality images of computer defined objects in real time. In addition, several input devices are easily implemented on such GWSs. Using these new technologies, we can not only see the motion of the objects in a sequence of CG images, but also manipulate objects defined in computer. If we can manipulate virtual objects with a hand in the similar way as real ones, we are able to have many experiences in various virtual worlds. Over the past few years, researchers have expended much effort to develop fundamental technologies[1]. One of the most important elements is simulating dynamic force of grasping object[2]. Another is considering multi-sensors for hand joints[3]. However, they cannot manipulate many objects intuitively at the same time, since it is difficult to calculate the objects interaction exactly[4]. Therefore, we developed a new geometric model for block manipulation with a hand in virtual space[5]. In this model, three basic hand actions are concerned such as grasping, moving and releasing. Since simplified gravity, inertia, and the motion on a floor are introduced in this model, blocks are naturally moved with interactive rate. This model has also a simplified interference check function among objects. Using this model, we realize a virtual block manipulation system with a hand based on a simplified physical rule, which responds in interactive rate.