VIRTUAL SITE : PHOTO-REALISM IN THE CLASSROOM

Transcription

1 VIRTUAL SITE : PHOTO-REALISM IN THE CLASSROOM I. Dickinson, R.C.T. Ellis, A. Riley, and J. Tenant School of the Built Environment, Leeds Metropolitan University, Leeds, LS1 3HE, UK ABSTRACT Virtual site is an on-line construction resource which enables users to interrogate photorealistic, three-dimensional, virtual construction objects and to explore linked panoramic scenes using a computer mouse or keyboard. The web-site (and hybrid CDROM) caters for children who are curious to know more about the construction process, for young people considering a career in the industry and for students in Higher Education reading for a construction-related award. Hence, Virtual site appeals to a wide variety of users, providing a vibrant and novel source of multi-media teaching and learning resources. Nodes embedded in panoramic scenes, via Realviz Stitcher, QuickTimeVR (QTVR) and VRWorx, allow learning resources e.g. construction details, careers information and URLs, to be accessed directly from the site. Moreover, QuickTime multi-row object movies give the illusion of being able to hold various items of equipment and construction materials. The case study illustrates the key stages in the development of QTVR movies and describes how directional sound can be added in order to create a stimulating and interactive environment. Whilst Virtual site is a HEFCE funded project, which can offer a range of teaching and learning opportunities in Higher Education Institutions, this case study concludes that the concept and technologies underpinning this project have widespread use beyond construction-related education. Examples of QTVR movies can be found in areas as diverse as property, design and experimental research. Accordingly, potential applications depend very much upon the client s needs and the skills of the system developer. Keywords: multimedia, panorama, object movies, construction.

2 INTRODUCTION Information and communications technology (ICT) offers exciting opportunities for educational development, whether this is for children working towards their SATs in primary school or for students reading for a degree in Higher Education. This case study outlines the development of one such computer-based learning resource, Virtual site, which finds application in a variety of educational settings 1. QuickTimeVR movies are linked together to create a photo-realistic construction site that users can wander through and explore. Moreover, drawing on the interactive approach adopted by many computer adventure games such as Myst and Riven, these scenes also provide an interface for accessing a variety of media, for example: photographs; sketches; movies; animation; detailed drawings; and quizzes. Hence Virtual site seeks not only to bring the construction site into the classroom, but also to encourage users to learn more about the people who are involved in construction and the processes necessary for the creation of the built environment. CREATING A WEB-BASED PHOTO-REALISTIC CONSTRUCTION SITE Development of the Virtual site interface is a three-stage process which comprises the assembly of panoramic scenes, the creation of linked QTVR movies and the establishment of a bespoke website. Panoramic scenes The principles used for the creation of digital panoramic scenes are similar to those that have been used by photographers for many years. With the aid of a camera and tripod, a series of overlapping images are stitched together in an appropriate software package. The field of view is improved simply by taking images in portrait mode and by the selection of an appropriate wide angle lens. The most time intensive method, although arguably the one which offers the greatest control over the final image, is to merge each image in a photo rendering package such as Adobe Photoshop (see Fig.1). A variety of tools enable the boundaries between individual images to be adjusted - correcting successive images for both exposure and perspective so that the final panorama appears seamless. 1

3 Figure 1: Individual images imported into Adobe Photoshop Alternatively, other applications are available which automate this process. For example, Realviz Stitcher, simulates the cylindrical nature of the image and, having assembled the images in the correct order, manipulates each image to provide the best possible overlap, before exporting the scene in jpeg format (see Fig.2). Adobe Elements performs similar operations. However Adobe s Photomerge command applies cylindrical mapping and advanced blending to adjust images for "bow tie" distortion, which occurs when perspective correction is applied, and to minimise colour inconsistencies resulting from blending images with exposure differences 2. Dependent on the precision with which the images are taken, the ragged edge of the panoramic scene is cropped to provide a regular image for exporting into VRWorx. Alternatively, Kaidan s 360 One VR optic 3 and PhotoWarp software offers a simpler, if more expensive, solution. 2 Adobe (2003) Adobe Elements User Guide 3

4 Figure 2: Images merged in Realviz Stitcher QTVR Movies Whichever photo-rendering package is used, VRWorx 4 creates a virtual panoramic movie by linking the left and right edges of the scene to form a cylindrical shape. The software allows the system developer to define the scale and window size of the finished movie together with the compression settings. A balance between file size and image quality must be achieved something that is particularly important when considering web or intranet delivery. VRWorx also enables multiple QTVR movies to be connected together, with multi-node scenes allowing the user to travel between various scenes to view the whole site. However, it was felt that the navigation in QTVR was not sufficiently clear for a first time user, therefore Virtual site uses a series of icons (developed in Adobe Photoshop) to aid this process. Hotspots are added over the icons and close-up images are linked back to the main movie, again with custom created icons (see Figs. 3 and 4). Figure 3: Icons created in Photoshop to aid navigation and content 4 VRWorx version 2, VR Toolbox

5 Figure 4: Icon to allow navigation back to main movie Web-site delivery Whilst it is possible to link panoramic scenes within a single QTVR movie, the issue of file size remains a key concern in the delivery of an internet resource. One means of reducing file size is to create hotspots in VRWorx, which function as HTML links to other scenes, before exporting each scene individually through VRWorx. Web pages are built using basic html which is edited within Dreamweaver. Embedding the panoramic movie within a web page allows a key for the icons and instructions regarding the use of Quicktime controls to be created. Virtual site has a virtual room interface, drawn from scratch in Photoshop, which enables users to become familiar with Quicktime controls and allows access to the construction site and other Virtual site facilities via a series of doors. A site plan on the webpage provides the user with an additional means of accessing the movies. Each movie is numbered and the scene that is currently being viewed is highlighted accordingly. Clicking on the number also takes the user immediately to the scene (see Fig. 5).

6 Figure 5: Virtual site website EMBEDDING MULTI-ROW OBJECT MOVIES WITHIN VIRTUAL SITE Inter-linked panoramic scenes characterise the development of Virtual site. However, object movies offer a valuable extension to this technology. Object movies give the user the illusion of holding some of the construction components that they have seen on site. Kaidan s object rigs, such as the Magellan M-2000, are custom built for photographing objects and, with the aid of VR Worx software, enable QTVR Object Movies to be created. Figure 6 shows an automatic optical level placed on the Kaidan rig. Figure 6: Kaidan s Magellan M-2000 Object Movie rig

7 A photograph is taken at every 10 degrees. The camera remains at 90 degrees on the same plane as the object. Each shot forms one part of a column within a complete row of 36 images. Care must be taken to ensure that the object is perfectly central on the turntable and that the camera is central to the object. A laser pen may be used to check correct alignment of the camera arm (see Fig. 7). Figure 7: Placing objects on the Kaidan rig Of course, single row object movies only allow the user to rotate an image in a horizontal plane. Therefore, to create a 360 degree (ten row) object movie, 360 photographs are needed. Photographs begin with the camera directly above the object pointing down and to eliminate camera wobble and thus blurry photographs, remote control is used (see Fig. 8). Figure 8: Half way through the shoot

8 Photographs are imported via iphoto (see Fig. 9) on a Macintosh G5 into VRWorx and compressed, before being exported as a QTVR object movie. Figure 9: Photographs stored in Apple s iphoto software Once complete (see Fig. 10) the viewer can interact with the object, revealing different views either by clicking and dragging the object with the mouse or by using the keyboard commands 5. Figure 10: Multi-row object movie 5 Proni, D. & Weisman, T.D. (1999) The VRWorx Integrated Authoring Environment for QuickTimeVR: User Manual, VR Toolbox Inc.

9 FUTURE DEVELOPMENT Ongoing developmental work is being undertaken to determine the most effective means of adding labels and hotspots onto multi-row object movies. The former will allow the user to view additional information about the object (see Fig. 11) whilst the latter, in the example given, might allow the user to take staff readings through the sight. Early attempts to insert labels, which fade in and out of the movie as the user rotates the object, have been both tedious and time consuming to produce, as they require labels at various perspectives and transparencies to be added to at least 15 stills. Figure 11: Labels created in Adobe Photoshop It is commonly acknowledged that the perceived quality of the visual image is increased by inclusion of sound. Moreover, sound can also be used to enhance the realism of an otherwise silent construction site. Experiments carried out using LiveStage Professional to determine whether sound can be added to QTVR movies have proved successful (see Fig. 12). As the user scrolls around the panoramic scene, directional sound e.g. a cement mixer, hammering or earthmoving plant, specific to the view is played. Many virtual learning environments in an educational setting are characterised by an array of icons which enable the student merely to download learning materials. Distance learning resources of this nature are often viewed as being sterile or cold 6. Interlinked QTVR movies offer an exciting opportunity to create dynamic interfaces that actively encourage users to interrogate the resources that are available. As such, these technologies are perceived to have widespread application in the educational sector. 6 Ellis, R.C.T., Thorpe, A. and Wood, G. (2003) Distance learning and postgraduate education in the Built Environment, CIB W89 International Conference on Building Education and Research, University of Salford

10 However, there are also an increasing number of websites in other disciplines that are making use of QTVR. For example: Keane Mahony Smith estate agents provide virtual tours of properties for sale ( Herman Miller Architects show QTVR movies of their National Design Centre in Chicago ( and LAB-VR uses panoramic pictures as an interface to gain access to scientific content developed in research institutions and laboratories ( A virtual tour of Beale Street in Memphis ( provides another interesting example, using both QTVR movies and directional sound to create a novel and immersive environment. Indeed examples such as these demonstrate the potential that this technology has to offer. Figure 12: QTVR movies amended in LiveStage Professional CONCLUSION Anecdotal feedback received during the Recent Advances in Built Environment Teaching (RABET) symposium suggests that this HEFCE funded project will complement other innovative FDTL funded construction-related education projects e.g. SITECAM, which seek to exploit the use of ICT. However, the nature and scope of Virtual site will be informed by the findings of RICS funded research 7, which seeks to capture children s views of careers in construction, and the views of students who have used Virtual site in the undergraduate curriculum. There seems little doubt that the technologies described in this case study have widespread use in an educational context. However, there is increasing evidence that interactive panoramic and object movies might have huge potential in the land, property and construction sectors. The authors of this case study would welcome suggestions and ideas on the future application of these technologies from academics, researchers and practitioners alike. 7 Keel, D., Hartley-Jones, S. & Ellis, R.C.T (2004) Careers in construction: what children have to say! COBRA Proceedings, Royal Institution of Chartered Surveyors, Leeds Metropolitan University.