3D User Interfaces: Theory and Practice

Part II: Hardware Technologies for 3D User Interfaces

One way to describe human–computer interfaces is as a means of communication between a user (or users) and a system. The user must communicate commands, requests, questions, intent, and goals to the system. The system in turn must provide feedback, requests for input, information about the system state, and so on. We can think of this communication process as a series of translations. The user and the system do not speak the same language, so the interface must serve as a translator or intermediary between them. In fact, there are multiple translation steps involved: the user first translates her goals into actions; next, the input device translates those physical actions into an electronic form for the system; finally, the system deciphers those signals based on the current system state. Typically, the system responds in some way to the input of the user, and so there must be some transformation of the input to produce the output—this is called a transfer function. To communicate this output to the user, the system translates the information into a digital display representation that is again translated by output devices into a form the user can perceive (e.g., light or sound), and finally, the user translates those perceptions into a meaningful semantic representation. The translations that occur between input devices and output devices are also known as control-display mappings.
In the end, though, all of this communication must use physical devices—hardware that serves as the medium of communication between the parties. This part of the book provides an overview of the hardware devices used to realize 3D UIs. Chapter 3 covers output devices, which present, or display, information to the user's perceptual system. Although visual displays are the most prominent type of output device for 3D UIs, we also cover auditory and haptic displays. In Chapter 4, we discuss input devices—the means by which the user gives information to the system. The goal of these chapters is to give you an idea of the types of technologies commonly used in 3D UIs, not to provide an exhaustive survey of current devices or to discuss the design of 3D input/output devices. Our focus in this book is on the software components of 3D UIs—components that include 3D interaction techniques (Part III) and that represent 3D UI metaphors (Part IV). Thus, if you are already familiar with 3D device technologies, you may wish to skim or skip this section and move on to Part III.

Chapter 3: 3D User Interface Output Hardware
Chapter 4: 3D User Interface Input Hardware


Devoted to the design and evaluation of three-dimensional user interfaces