返回Google圖書搜尋

Frames of Reference and Direct Manipulation Based Navigation

其他書名	Moving in Virtual Architectural Space
出版	Technische Universiteit Delft, 2005
ISBN	90901914889789090191485
URL	http://books.google.com.hk/books?id=ZmtQAAAAMAAJ&hl=&source=gbs_api

註釋"Although highly advanced in visual realism, current virtual reality systems used by designers do not provide the user with the ability to interact effortlessly and move in space as desired as one does in real space. As a result, these systems offer limited help to designers when they want to test or communicate the spatial quality of their projects. The aim of the research was to develop a design tool for navigation in virtual environments that can offer a sense of 'immersion' and vividness similar to that experienced when one moves in real space. The research examined a number of typical cases of CAD-VR navigation systems and analyzed their performance. All programs use direct manipulation: a virtual representation of reality is created, which can be manipulated by the user through physical actions like pointing, clicking, dragging, and sliding. The analysis showed that the lack of realism of these systems means that they do not offer a 'sense of reality' because of the user's inability to interact easily with the computer to navigate among represented objects. The user cannot: 1. Plan a course from a given location to a desired one; 2. Shift the direction of their gaze and focus attention to objects as they move across a path; 3. Move around an object keeping track of this change in relation to the surrounding objects; 4. Turn an object in front of the viewer in order to examine it. This lack of 'sense of reality' cannot be simply improved by adding attributed to the system that are more realistic - details, shadows, and reflections. Departing from pioneering rigorous studies developed in environmental design by Kevin Lynch and his followers about 'cognitive mapping', and drawing on recent research in cognitive science on spatial thinking, the study identified the cognitive processes through which people perceive their environment as they move through it. In contrast to Lynch's approach concerned with the visual quality of urban environments focusing on visual urban cues for recognition and orientation within a city, the present research, related to movement through the built environment, concentrated on the linguistic commands. The 'frames of reference' people use to plan their path among objects, shift their attention to them, move around them, and turn them. The frames of reference used are: 1. allocentric; 2. egocentric; 3. relative; 4. intrinsic, and 5. absolute. Following the criteria of realism and vividness in exploring the virtual world through movement, the system uses an agent/avatar which is an immersed character that allows the user to direct navigation and the view of objects. It permits both agent-based and object-based navigation. The user can refer to the movement of the avatar as a basis for movement or to the object as a reference point. To enhance the feeling of engagement, the user's input to the system requesting a change of viewing position, direction of view, object of view, or a path, or a view, is expressed in terms of natural language while the output remains visual. In other words, the user talks to the avatar and, at the same time sees on the sreen what the avatar views in the virtual world. The user-centered navigation tool produces 'on the fly' navigation most desirable for design professional applications as opposed to a tailored presentation. It can be applied in urban environments as well as in architectural interiors, both using the same types of axes and frames of reference. It is targeted to support testing of the quality of designed environments, both interior and exterior, by individual designers, but it can be most effective in architectural presentations and debates where the architect communicates with various parties, while examining the various aspects of the three-dimensional project"--Page i-ii.