Interactive Virtual Tour Technology - Assignment Example

RUNNING HEADER: Interactive Virtual Tour Technology Report PAGE RESEARCH REPORT ON INTERACTIVE VIRTUAL TOUR TECHNOLOGY Field of study Faculty 11 April 2006 ABSTRACT The report contains the research undertaken on Interactive Virtual Tour Technology, its current applications, the technologies that can be used by developers to create Virtual Tours, and the possible future applications it can be used for. Research was done using internet resources on tutorials, papers, articles and journals to compile a comprehensive overview of current development trends and methods, including a extensive reference list that can be used by future students and application designers to not only design and develop Interactive Virtual Tours but to expand on its current applications. CONTENTS TERMS OF REFERANCE 3 1.SUMMARY 3 VIRTUAL TOUR TECHNOLOGY 5 Overview 5 Virtual Tour Technologies 6 PRACTICAL APPLICATION ANALYSIS OF VIRTUAL TOUR TECHNOLOGY 7 VTT Practical Application Overview 7 Virtual Tour Resources 8 CRITICAL EVALUATION OF INTERACTIVE VIRTUAL TOUR TECHNOLOGY AND ITS APPLICATION 10 VT Technologies Overview 10 Photographic equipment 10 Table 1: Comparison of Types of Cameras used for Panoramic Images 12 Image 2: Comparison of different lenses used 14 Computer Hardware Requirements 14 EVALUATION OF SOFTWARE USED IN DEVELOPING VIRTUAL TOURS 16 Introduction to VT software 16 Image Touch-up and Stitching 16 VT Software Products and Reviews 17 Software and Applications to make VT Interactive and Install to Internet 20 CHALLENGES EXPERIANCED WITH VIRTUAL TOUR TECHNOLGIES BY DEVELOPERS 21 THE FUTURE OF VIRTUAL TOUR TECHNOLOGIES 22 CONCLUSION 22 REFERANCE PAGE 23 James Rigg. Choosing equipment. Last modified: 20 January 2006. Panoguide. Accessed 13 April 2006. 24 James Rigg. Product Review. Last modified: 20 January 2006. Panoguide. Accessed 13 April 2006. 24 TERMS OF REFERANCE GPS Global Positioning System IVT Interactive Virtual Tour VT Virtual Tour VTT Virtual Tour Technology IVRPA The International VR Photographic Association QVTR QuickTime VR Application Programmatic Interface 1. SUMMARY Interactive Virtual Tours is an application that was developed for promoting locations and products on the internet, or for individuals to share their experiences with others. With computers and high-speed network technology evolving faster, offering users the ability to download more data faster, quality high resolution Interactive Virtual Tours are fast becoming very popular with Internet users. IVT's offer internet users the ability to sample facilities, places and products before they spend money, it also give people the ability to visit places they may never be able to. IVT developers use several types of technologies in the development process of creating IVT's. This technologies range from cameras and computers to several VR software packages, depending on the requirements, quality and funds of the developer. The development process starts with taking several photographic images, to capture a 360 degree view of a location. These images are then digitized onto a computer, re-touched and colour graded with a photo editing software package. After which the images are stitched together to form a panorama of the location with a VT stitching software. Then the panorama is coded using a browser plug-in or a Java runtime engine to make it interactive, after which it is installed on the web for users to view. The developer of IVT's face many challenges during the development process that he needs to solve. The quality of the completed IVT application will depend on the developer's skills, abilities and on what type of technologies and software he utilised. Currently there is a wide range of VR software packages on the market. Some for beginners and hobbyists and others for professionals, the difference in complexity, ease of use and price. The cheaper the software the higher the learning curve and the more complex its applications. The VT technology is already used for a rage of applications is being further developed by software companies, students and programmers. This may expand the use of VTT into other fields, such as combining it with GPS or as a early information system for firemen. VIRTUAL TOUR TECHNOLOGY Overview Interactive Virtual Tour (IVT) for the purpose of this report describes a photo image, normally found on the internet, of a place such as a building, facility or park of which the view can be navigated via the movement of the mouse. This gives the participant or viewer the ability to explore a 360 degree view of the place and could include the ability to have an up or down view. Internet users can through IVT, explore and experience, by controlling and looking at the changing image, scenes from around the world. Web page owners use this technology to sell property, promote products, to advertise holiday resorts, or to give an impression to others of their individual experiences. By offering a Virtual Tour to visitors, Web page owners not only promote their pages and its contents, but also make it more interesting, ensuring visitors will return and tell others about the site. A simulation is an imitation of some real thing, state of affairs, or process. It is an artificial situation or environment. Simulation may refer to a VR world or a simulation of probabilities. Simulation creates the appearance of being real, giving the experience of a real situation," (Simulation 360, 2006). To develop an IVT the developer needs to use a range of different technologies, from digital cameras and tripods, to computers with the required software and interface's. The completed IVT can then be hosted on either the internet or on CD's, DVD's, and even mobile phones. The development of an IVT will give any person or student a wide range of skills and experience of different technologies, and could be used as a comprehensive educational tool by institutions. Virtual Tour Technologies To establish what types of technologies are required to develop an IVT it is necessary to break down the development process into separate tasks and processes, and then attach the technologies used in each. The processed used as a base case is the tutorial written by Matt Byrnes in his tutorial on creating a VT using Flash 4 software. Following is the process followed in the tutorial: Planning the VT - Writing down what location will be used to create a VT and what the objectives and processes are in a logical order and what equipment would be needed. Sourcing equipment - The task of acquiring and getting access to the necessary technologies. Taking the pictures - Using a camera and tripod and following the required format, capture picture images as per VT plan. Downloading pictures to computer - Connect camera to computer and download images onto hard drive, using unique numbering system categorizing and grouping them in relevant order. Stitching images together seamlessly using software - Using software build panoramic images aligning relevant images in such a way that no seam can be observed. Draw Panoramic images into Flash software - In this process the developer uses Flash software and codes to make the images interactive. Testing IVT - Developer draws IVT into a Web browser such as Internet Explorer and tests its functionality. Upload IVT to Web page - Developer uploads IVT to an internet host where the relevant Web page is located and create a link, Web users can click on to view the IVT. Following the above breakdown of the creation process it is obvious what technologies will be needed to create a VT, such as photographic equipment, to stitching and hosting software. It must be stressed that there are many types of technologies available that can be used to develop IVT's, from different kinds of photographic and video equipment and computers, to a range of software products. The internet offers a wide selection of software that can be used to create IVT's, some are free and others have to be paid for. The difference is in the complexity and the amount of functions each has, and also in how the IVT will look and function in the end. PRACTICAL APPLICATION ANALYSIS OF VIRTUAL TOUR TECHNOLOGY VTT Practical Application Overview IVT's has come a long way from just normal images on websites, to full interactive images, which can be navigated by the viewer through a controlling device such as a computer mouse. Many organizations, businesses and individuals have now incorporated IVT into their Web pages for a number of different reasons. Universities and Collages use it to give prospective students a view of their facilities, NASA use IVT to educate and inform visitors to their Web site on astronomy, space travel and planets. Resorts such as parks and wildlife sanctuaries incorporate IVT to give visitors a glimpse of what they offer and the sights people can see. Hotels use IVT to give travelers a view of their available facilities and services, which makes travelers feel comfortable in making a booking. Real Estate business use VT to give prospective buyers the change of touring houses on offer at their own leisure using the internet, reducing the time and expense of taking customers for location visits. Businesses use IVT to exhibit their products, such as automobiles giving the customer the option of changing the color, wheels or any other accessory in a virtual world to get an impression of how it will look in real life. Individuals develop VT's of their travels and conquests and host them on the relevant Websites so that others can share their experiences. Currently there are thousands of such VT's on the internet, developed using a wide range of technologies. Even towns and cities promote themselves to prospective investors and travelers through a combination of IVT's and Web cams. Virtual Tour Resources Annette Hall has created a list of some of the more exceptional VT sites on the internet, which are: Virtual Tour of Alcatraz Virtual Tour of Antarctica Antarctica Icebreaker Ship Virtual Tour Comcast Center Virtual Reality Tour Great Barrier Reef Interactive Site An Interactive Tour of Ellis Island Yerba Buena Gardens Virtual Tour Virtual Tour of Yosemite National Park Tour Old Faithful at Yellowstone National Park Virtual Tour of Hawaii Random Virtual Tours of Scenic Locations Virtual Tour of The Taj Mahal Explore St Paul's Cathedral Mars Project Virtual Reality Tour Air Force CF-18 VR Tour Virtual Tours of Southwestern U.S. Deserts Virtual Moon Atlas - Free software for Moon observation or survey Virtual Links - Virtual British Tours Virtual Links - Internet Sites that use VR Some VT sites from the open source directory of developers, organizations, businesses and places: American Home Tours A Birds Eye 0-360.com 360 Degree Virtual Real Estate 360-i Virtual Tours Europe NYM Virtual Tours RTVFLA - Real Tour Vision of Florida San Francisco Real Estate Virtual Tours 360 Spin Tour Now Network Virtual Audio Tours Virtual Tours of Virginia Vista Virtual Tours CRITICAL EVALUATION OF INTERACTIVE VIRTUAL TOUR TECHNOLOGY AND ITS APPLICATION VT Technologies Overview As deducted from the steps in creating an IVT, the technologies used range from cameras to computers with the required software. The software used for IVT will be covered in the next section. This section will critically evaluate the means and technologies used for capturing images and digitizing them onto a computer, ready for the developer to create the IVT. Photographic equipment To begin it is necessary to have access to a camera; any camera will suffice even a disposable one. But the more basic the camera the higher the effort will be to capture the images effectively and to digitize it to computer. In addition the quality of the images will be directly linked to the quality of camera used, and if pictures was taken from the hand or from a tripod. There are panoramic cameras on the market that is especially developed to capture panoramic images and can be seen as high end equipment, which is very expensive. This to evaluate available options a comparison of available equipment needs to be done. Advantages Disadvantages Film some people claim film cameras still produce better quality than even the best digital cameras film cameras are cheaper than digital overall cost is higher than digital because of the cost/time required to digitize the film Digital see the pictures immediately on-camera (re-shoot if you make a mistake) fast to process no scanning, colour correcting or dust marks to remove quick to learn how to get good results Rotating panoramic camera Shoot a panoramic picture in one shot, not several No stitching required for 360 degree panoramas Very expensive compared to 'standard' digital or film cameras Steep learning curve Processing of special large format film is more expensive Cannot be used for 'normal' photography as well as panoramic Parabolic mirror Shoot a perfect 360 degree shot in one go No stitching required. Ever. Moving subjects not a problem No other special equipment required Very easy Not compatible with all cameras Creates cylindrical not spherical panoramas (spherical is possible with multiple shots and special software) Picture has to be digitally processed to convert it into a panoramic image (software is supplied by the mirror manufacturer) Resolution of the final picture is limited to the maximum resolution of a single picture shot with that camera. Table 1: Comparison of Types of Cameras used for Panoramic Images It is also advisable to use a high quality tripod, as it is difficult to capture several images by hand, each at the correct level needed for seamless stitching. High quality tripods give a very smooth motion during panning, which will prevent wobbling images. The weight of the camera is also an important factor in determining what the best tripod would be. In conjunction with the tripod a spirit level will be invaluable in ensuring the camera is level, preventing a mismatch on completion of a 360 degree shoot of the first and last images. It is also advisable to use a remote shutter release device, which can be an infrared or wire remote control. This will prevent any shaking or slight movement of camera during shutter release. Then the photographer needs to keep the fault of parallax in mind. As the camera pans the centre point will be in the middle of the camera and not the lens. Although a small inaccuracy it may influence the final VT. To prevent this, a panoramic tripod head can be used which will ensure that the centre of the lens is above the point of rotation and that the camera is rotating about a point in the lens. Image 1: Demarcation Plates So how many images do the photographer needs to take to get a full 360 degree image If a normal 35 mm lens is used 24 equally spaced demarcations should be indicated on a plate attached to the tripod or panhead, and this 24 pictures needed to be taken by aligning the lens direction marker with each demarcation. This can be reduced to 16 or 12 depending on what types of lenses are used. Using wide angle lenses the amount of pictures for a 360 image are drastically reduced, and even more so when using a fisheye lens, as only 2 or 3 pictures will be needed. But when using wide angle or fisheye lenses it must be realized that available stitching software will support either rectilinear (normal) or fisheye lenses, very few support both. garden scene after stitching, 18mm lens field of view: 360 x 90 degrees number of pictures required: up to 12 garden scene after stitching, equivalent to a 38mm lens field of view: 360 x 56 degrees number of pictures required: up to 20 Image 2: Comparison of different lenses used Another option to using wide angle or fisheye lenses is to use a parabolic mirror, which will not only reduce the amount of pictures, but will also give the same effect as if using a fisheye lens. However a special mirror, mounting bracket and software will be needed. Image 3: Parabolic Mirror Computer Hardware Requirements Next we need to evaluate the computer requirements as this will be the technology used for digitizing, stitching, developing and testing of the IVT. A desktop computer will be adequate for a developers needs, but a laptop will allow much more flexibility during the development process. Evaluating system requirements of the most often used VT software, the following are the suggested hardware requirements to be able to develop and view IVT's. Hardware Requirements: PIII800MHz or faster processor 512M RAM or more (1 G RAM recommended to stitch panorama over 6000*3000) Network interface card or modem must be installed USB ports 100M of free hard disk space or more Video display of 800*600 pixels or higher with 256 colors Scanner (If using film) Operating System Microsoft Window9X/ME/NT4.0/2K/XP or later OS Others Microsoft IE4.0 or Netscape Navigator 4.5 or later version. Java Virtual Machine. JRE (Java Runtime Environment) 1.4.1 or later version To view QTVR (*.mov), QuickTime 5.0 or later versions is necessary. EVALUATION OF SOFTWARE USED IN DEVELOPING VIRTUAL TOURS Introduction to VT software As explained earlier in the report a range of software are needed to develop and view IVT's. Firstly looking at what software will be needed to view IVT's on the viewer's computer, it is best explained by the International VR Photographic Association (IVRPA). There are various players for viewing VR movies, and they differ greatly in quality and performance. There is Apple Computer's QuickTimeVR (QTVR), PTViewer, and a few other Java-based players. Java will play VR in a limited way on computers that do not have QuickTime. Java-based PTViewer has many limitations compared to QuickTime VR, but offers a basic VR tour and has the best quality of the Java players. QuickTime VR is the most widely recognized player with superior quality and excellent performance. QuickTimeVR is the industry standard for photo-realistic virtual tours. Because QTVR is part of QuickTime, there are many unique features and useful benefits to using it, and it offers an open-ended ability to customize the VR being created. With QuickTimeVR a highly interactive and high resolution VR experience is possible, and this is the wave of the creative future (IVRPA, 2001 - 2004). Image Touch-up and Stitching After images has been captured and digitized to computer the VT developer needs to touch-up the photo images with a photo editing software package such as Photoshop CS. During this process colours are made sharper, light and shadow effects are added or removed and images are colour graded to insure no difference can be noticed when stitched together. Then VT software is used to stitch the images together in the correct order to create a panorama of the location. Virtual Tour software comes in a variety of configurations from automatic to complex, from free to expensive; depending on the requirements of the VT developer the end result can vary dramatically. VT Software Products and Reviews There are many VT software on the market and they differ in price and complexity. Some target the hobbyist and others the professional photographer and or IVT developers. The choice of software will depend on the IVT requirements and the skills and experience of the developer. Below is a short list of some of the available software specially used for creating VT's. Some are for beginners and hobbyists, and others for professionals. Several of the following software has been available for a period of time and its functionality have been tested by a wide range of users, others are fairly new and little or no information can be found at this time. ADG Panorama Tools (Albatross Design) Cool 360 (Ulead Systems) Cool 360's graphically rich interface not only simple to use but at the same time gives a tremendous amount of control over panoramas. Unlike some automatic stitching applications this allows the creation of a 'project' and save to disk all the settings used for stitching a panorama from a particular sequence. Cool 360 allows the adjustment of the perspective of individual images to compensate for camera tilt. Also completed panoramas can be embedded in MS Office documents, saved in a self-executing format (the viewer is embedded in the file) and emailed. In addition to brightness and contrast controls there is a colour (hue) adjustment. Cool 360 does not support fisheye lenses, however it does support lenses with focal lengths down to. D Joiner (D Vision Works) D Joiner can create cylindrical, spherical and planar panoramic images and also output spherical images in cubic format. As well as just outputting images it can also generate a simple web page by using its own Java applet viewer. Stitching is done manually and can be a time consuming process HotMedia (IBM) HotMedia is a simple authoring tool for creating Java based presentations including panoramas. It can create animations of images, display movies, VRML objects and display cylindrical panoramas as well as spherical iPIX movies. Developers can also extend it further if they know HTML and JavaScript, and add additional interaction within the web page. HotMedia is not designed specifically for creating virtual tours, so it is not necessarily obvious how to use it to create a virtual tour. Image Assembler (PanaVue) Image Assembler's interface is very easy to use, and has a very powerful fully automatic stitch function. It has manual stitching capabilities and the manual alignment flags make Image Assembler extremely easy to use and very powerful. The software supports a huge range of image formats for both source files and for saving the final panorama, including QTVR. Panoweaver (Easypano) Panoweaver is possibly one of the simplest and easiest panoramic image stitching programs. The main reason for this is that it is designed exclusively to work with just two hemispherical images shot back to back. This in turn means that it can quickly and easily stitch a fully spherical panorama in which a person can look straight up and straight down. It supports uncompressed source images such as TIFF and Targa (TGA) and can save in uncompressed formats too including multi-layer PhotoShop (PSD) and as Targa. Panoweaver makes it very easy to create web pages or record image to CD. In fact it not only can export VRML cubes for use with VRML, JPEGs for use with Java applets and QuickTime format files, but it will also create a web page for any of these Helmut Dersch's PT Viewer is included and is the Java applet that is used to create a Java web page. PhotoShop Elements (Adobe) PhotoVista Panorama (ISeeMedia) PhotoVista Virtual Tour (ISeeMedia) PTViewer Scripter (Easypano) QuickStitch 360 (Enroute) QuickTime VR Authoring Studio (Apple) REALVIZ Stitcher (REALVIZ) Smart Viewer (Stitch Fisheye) Stitch Fisheye Pro (Stitch Fisheye) Software and Applications to make VT Interactive and Install to Internet When the developer has completed stitching and re-touching of the panorama's the next step is to develop interactive controls, this creating an IVT and preparing it for Internet installation. Virtual tours can be deployed using plug-un or Java technologies. A plug-in is a helper application which works within a Web browser, or as a stand alone application. Plug-ins enhances browser capabilities and enables playing a wider and more robust selection of Web media. Java is programming languages build into Netscape, Microsoft and AOL versions 3.0 and later Web browsers. With Java a plug-in is not required to play VT's, but it lacks the performance and enhanced features and capabilities of plug-ins. The most popular software used for preparing IVT's for the Internet is QuickTime VR Application Programmatic Interface 2.0 (QVTR 2.0). With the QTVR 2.0 API, it is possible to create novel playback engines which may have localized sound playback, unique user interfaces for multi-node panorama navigation. With the QTVR 2.0 API, the possibilities are wide open for creative playback and interaction of QuickTime VR content. CHALLENGES EXPERIANCED WITH VIRTUAL TOUR TECHNOLGIES BY DEVELOPERS During the development process the developer will be faced with many challenges. Normally the first problem arise when images are digitized and there is a mismatch between first and last image, due to camera not being level when photo's where taken. In addition a gradual change in light can result in a mismatch between images and colour correction will then have to be done. Then depending on the level of software used for stitching, it can be a very complex process if free software is used, or it can be easy when expensive software with click and drag functions is used. During stitching problems can be experienced if there is too little overlap between images and if images were not taken at the same level. This problem can normally be solved by cropping the panoramic, which of course reduce the size of the panoramic. On completion of stitching panoramas needs to be prepared for Internet installation. During this process an application software needs to be used to make panoramic interactive and create a virtual runtime engine for Java, or a browser plug-in for Quick Time. During this process developers can experience hotspots on the image during coding, which makes the control of the image unstable, resulting in users getting lost in the image interface. This can be solved by using different application software or by linking different nodes to an overview. So user will link back to the overview when navigating to another section in the IVT. THE FUTURE OF VIRTUAL TOUR TECHNOLOGIES Virtual Tour Technology has already come a long way since its firs use on the internet. It is a recognized promotional application, already extensively used by organizations, institutions and individuals. Currently there are thousands of software developers working on improving the technology and with the fast evolution of computers and high-speed network technologies, it is expected that IVT will be further enhanced and be used for many additional applications. Global Positioning Systems (GPS) popularity is growing as it allows people to take the closes route to their destination. By combining GPS with IVT technology, users will be able to not only follow the basic indications given by a GPS, but will also be able to see and recognize landmarks along their route. Further, firemen may find an IVT hand held unit very helpful when they need to enter a building or skyscraper. Through applying IVT technology, they will be able to get acquainted with the inside of a location before they even get there. By building up an IVT data base of all the buildings in their area, it may increase their ability to respond when there is a fire. CONCLUSION The uses for IVT will definitely increase in the future as further development of the technology is currently being done by software developers and companies. Combined with the fast evolution of computers and high-speed networks, higher quality, more comprehensive IVT can be developed and accessed by Internet users or written to CD or DVD for promotion and marketing, to inform or educated people, or to be used in combination with other technologies such as GPS. For educational institutions IVTT offers a great opportunity to educate IT or Art students in a range of technologies. This field may give students additional skills and experience that can hold great value for them on completion of their studies. In addition students could help develop a library data base of the surrounding area or town, and if most universities or colleges contribute a vast virtual resource could be created. REFERANCE PAGE I. Yes San Francisco. Virtual W Tour. 2002 - 2006. Accessed 10 April 2006. http://www.virtuar.com/virtualwtours.htm II. Simulation 360. Definition of Virtual Simulation. 2006. http://www.mengkilapx3.com/M3-CTECH/simulation360/about-simulation360.htm III. Matt Byrnes. Virtual Reality Tours in Flash. Actionscripts. Accessed 12 April 2006. http://www.actionscripts.org/tutorials/advanced/Virtual_Reality_Tours_in_Flash/index.shtml IV. Annette Hall. Virtual Geography - Google. 1998 - 2006. Reliableanswers. Accessed 12 April 2006. http://reliableanswers.com/hs/virtual_geography.asp V. Open Directory Project. Virtual Tour. 16 March 2006. DMOZ. Accessed 12 April 2006. http://dmoz.org/Computers/Software/Industry-Specific/Real_Estate/Virtual_Tour/ James Rigg. Choosing equipment. Last modified: 20 January 2006. Panoguide. Accessed 13 April 2006. http://www.panoguide.com/howto/panoramas/spherical.jsp VI. SiteGuy. Basic Photographic equipment: Needed to Create QTVR Panoramas. 1997. OutsideThe Lines. Accessed: 12 April 2006. http://www.outsidethelines.com/BuyHW.html James Rigg. Product Review. Last modified: 20 January 2006. Panoguide. Accessed 13 April 2006. http://www.panoguide.com/products/ VII. The International VR Photography Association. What is VR 2001 -2004. IQTVRA. Accessed: 11 April 2006. http://www.iqtvra.org/iqtvra/docs/en/index.phpincludeFile=1.About_Us.dir/1.What_is_VR.php VIII. Alcatraz QuickTime VR Tour. http://www.nps.gov/alcatraz/tours/qtvr/ IX. Center for Astrophysical Research in Antarctica. Antarctica VR Tour. http://astro.uchicago.edu/cara/vtour/ X. Antarctica Icebreaker Ship Virtual Tour. The Ship. SeattlePI. http://seattlepi.nwsource.com/antarctica/ipix/ XI. 360 degree panorama of the Clark School of Engineering. Last updated: 04/01/2006. University of Maryland. The Ship. SeattlePI. http://www.it.umd.edu/VR/Comcast/ XII. Virtual World. The Great Barrier Reef. 1996-2006 National Geographic Society. http://www.nationalgeographic.com/earthpulse/reef/reef1_flash.html XIII. Interactive Tour of Ellis Islands. 2006-1996. Scholastic Inc http://teacher.scholastic.com/activities/immigration/tour/index.htm XIV. Yerba Buena Gardens, August 07, 2002. Copyright2002 Yes San Francisco, LLC. All Rights Reserved. http://www.virtuar.com/ysf2/ap-Yerba-Buena.htm XV. Live Yosemite Web Cam. http://www.yosemite.org/vryos/ XVI. Old Faithful Area Tour. Last Updated: 22-Dec-2004. http://www.nps.gov/yell/tours/oldfaithful/index.htm XVII. Hawaii Island Virtual Tour. 2004. VTHawaii.com http://www.vthawaii.com/ XVIII. Random Visual Tours. Bludocks. 2004 http://www.vrtour.it/v2/en/ XIX. Explore the Taj Mahal http://www.taj-mahal.net/index.htm XX. Explore St Paul Cathedral. http://www.explore-stpauls.net/index.htm XXI. Mars Project. Virtual Tours. 2003 http://marsproject.com/tour.htm XXII. Canadian Air Force Public Affairs. Cf-18 virtual tour. Last updated: 2004-08-17. http://www.airforce.forces.gc.ca/equip_vr/vr_tour/index_e.asp XXIII. Dessert USA. National Parks. 1998 - 2006. http://www.desertusa.com/qtvr/du_qtvr.html XXIV. Virtual Moon Atlas. 25 October 2005. http://astrosurf.com/avl/UK_index.html XXV. British Tours. 2005. British Tours Ltd. http://www.britishtours.com/360/index.html XXVI. Internet Sites that use VR. Updated: 23 June 1999. http://comers.citadel.edu/vr/vr-sites.htm XXVII. Concepts In Motion. Quick Time VR Content Creation. 1997. http://www.outsidethelines.com/QTVRProgramming.html XXVIII. Studio 360. Creating a virtual tour. http://www.studio360.com/virtual-tour.htm Read More