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Visual Communication in Urban Planning and Urban Design
3. Photorealistic Media in the Process of Communicating Plans
3.1 Development of Photorealistic Media
In contrast to the solid or block modelling discussed, a number of software companies, have developed photospatial VR systems for use on a variety of operating systems. Apple's QuickTime Virtual Reality (QTVR) is characteristic of a range of WWW development tools utilising photo-realistic scenes to create navigable movies. QTVR has the largest user base, with over 3000 sites on the WWW. Realism is achieved by using photographic rendering, allowing a user to pan around the scene or node.
Whilst photographically rendered scenes are highly realistic, the user's view point is fixed to the original location of the camera. The user is not able to `walk' around the scenes in the same way as in VRML, but nodes can be linked allowing users to `jump' between scenes, creating a sense of movement. Typical file sizes for QTVR are 200 - 300Kb for each node, placing a restriction on movement as each new node is downloaded separately as the user moves around. The development of a WWW interface featuring panoramic scenes may be viewed in two distinct stages as illustrated in Figure 20.
Stage one consists of the development of the panoramic scene, such as Leicester Square, London. Each scene consists of approximately 14 photographs, depending on the camera lens used. The photographs are taken, in this case using a digital camera, allowing each to overlap by approximately five percent. The images are then `stitched' together to produce a full 360 panorama using specialist software such as PhotoVista which is produced by LivePicture (http://www.livepicture.com). Once the panorama have been produced, they can then be integrated into a WWW page, Stage two. There are currently two routes to integrating panoramas into the WWW, the `plug-in' and the Java route. The first route uses software specific `plug-ins' typically written for either the Netscape or Microsoft range of browsers. The use of `plug-ins' allow the integration of additional information into the panoramic scenes but often requires the end-user to install the `plug-in' on to the client machine. Furthermore, `plug-ins' are usually operating system specific and therefore implicitly restrictive.
The second route to placing photo-realistic VR panoramas on the WWW is by using JAVA applications or applets. JAVA applets capable of displaying panoramas are freely available on the WWW (http://www.livepicture.com) thus allowing scenes to be integrated into platform independent WWW pages. The level of interactivity within the JAVA based scenes is at present limited in comparison to the `plug-in' counterparts. For example, it is much more difficult to link scenes and gain `clickable' information within the Jutvision JAVA environment in comparison to the equivalent Windows 95/ NT `plug-in'.
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