3, 4, and 5. In this chapter, we focus on the computer technology for the generation of VEs.

One possible organization of the computer technology for VEs is to decompose it into functional blocks. In Figure 8-1, three distinct classes of blocks are shown: (1) rendering hardware and software for driving modality-specific display devices; (2) hardware and software for modality-specific aspects of models and the generation of corresponding display representations; (3) the core hardware and software in which modality-independent aspects of models as well as consistency and registration among multimodal models are taken into consideration. Beginning from left to right, human sensorimotor systems, such as eyes, ears, touch, and speech, are connected to the computer through human-machine interface devices. These devices generate output to, or receive input from, the human as a function of sensory modal drivers or renderers. The auditory display driver, for example, generates an appropriate waveform based on an acoustic simulation of the VE. To generate the sensory output, a computer must simulate the VE for that particular sensory mode. For example, a haptic display may require a physical simulation that includes

FIGURE 8-1 Organization of the computer technology for virtual reality.