Engineering Computational Technology
Chapter 2 W. Thabet+, M.F. Shiratuddin+ and D. Bowman*
+Department of Building Construction, *Department of Computer Science, Virginia Tech, Blacksburg, Virginia, USA Keywords: virtual reality, virtual environments, immersive, interactive, design, construction planning, visualization, CAVE, 3D modeling.
During the last two decades, the word virtual became one of the most exposed words in the English language [1]. The Webster dictionary defines it as ``being such practical or in effect, although not in actual fact or name." What we refer to as reality is based upon something we call the external physical world [2]. Therefore, a virtual reality seems to suggest a reality that is believable, and yet does not physically exist. Isdale [3] indicated that different people assign different meanings and interpretations to the term virtual reality (VR). To some people, VR is a specific collection of technologies, while others stretch the term to include conventional books, motion pictures, radio, etc. - any medium that can present an environment that draws the receiver into its world. In this paper, the term VR is restricted to real-time, three-dimensional (3D), computer-mediated systems. This involves the use of computers to create and display 3D scenes allowing user navigation and interaction. Navigation includes the ability to move around and explore features of the 3D scene, and interaction implies the ability to control the virtual environment in other ways as well, such as manipulating virtual objects. Interaction with the virtual world is a critical test for a virtual reality. Since the early 90's, VR has matured considerably, and has begun to offer many powerful solutions to very difficult problems. New visual display devices coupled with new complex graphics cards capable of generating high-end computer images have appeared. Other devices that provide auditory (sound) and haptic (touch) displays to complete the illusion of realism have been greatly improved. More flexible and powerful software systems geared towards generating real time virtual environments have also become available, with better features and capabilities. VR is no longer a technology looking for applications, but rather is a solution to many problems that involve real-time visualization of complex data. Simultaneous with these developments, the term `Virtual Reality' has been gradually ignored by some in preference for the term `Virtual Environments' (VE). The use of the VE term avoids any possible implication that there is any ambition to remodel the universe [2]. Other terms that have been used include visually coupled systems, synthetic environments, cyberspace, artificial reality, virtual presence, and simulator technologies. For the purpose of this paper, the terms virtual reality (VR) and virtual environments (VE) will be used interchangeably. Various industries are continuing to explore the best ways to use VR within their own sectors. VR has played a significant role in flight training over the past two decades, and will continue to do so in the future. Virtual modeling also continues to have an important role in various industries such as aerospace, architecture, education, medicine, manufacturing etc. VR models are used alongside with physical models for visualization, simulations and assessing new servicing and manufacturing strategies. What can construction project stakeholders do in a 3D virtual environment? They can actually ``climb inside" a building and visualize its elements and components from any visual perspective to evaluate the design and make modifications. They can virtually ``disassemble" the components and ``reassemble" them repeatedly to rehearse the construction process, develop a construction sequence, assess the constructability of the design and identify potential interference problems. They can take unlimited virtual walkthroughs of the facility and experience, in a realistic way, what to expect when construction is complete. Various efforts in industry and academia are underway to explore these possible benefits of VR in construction. As a result, the trend of utilizing computer models and real-time VR simulation in construction is growing. This paper provides a summary of the different categories of VR systems, and the current hardware and software technologies used for VR implementations. The paper also presents a detailed overview of some current applications and research projects of VR in construction. The intention is not to provide an exhaustive list or a complete review, but rather to provide some examples of what has been implemented to make the readers aware of current technology and applications of VR in construction, and point them in the direction of more detailed references. It should be noted, however, that there is much more work to be done in this field to explore its tremendous applications that can greatly benefit the construction industry as a whole.
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