Contents:

• Overview
  
• Collection FAQs
  
• The Virtual Reality Interface
  • Known Bugs
    
  • Using the Search Column
    
  • Using the Index Cards
    
  • Viewing and Downloading Files
    
• Viewing Still Images
  
• Viewing QuickTime Environments
  
• Viewing Virtual Reality Worlds
  
• Viewing Computer-Aided Design Models
  
• Viewing Documentation
  

Overview:

The Perseus Virtual Reality Collection contains digitally rendered

• Still images,
• QuickTime movie, object, panorama, and panoramic movie environments,
• Virtual Reality Modeling Language worlds, and
• Computer-Aided Design models.

The virtual reality content can be displayed using Perseus' established tools for viewing images. For example, a search for "King William Street" using the Perseus Lookup Tool provides a list of the related content contained in the Perseus Digital Library. Links to the various types of virtual reality media are included in this list. The virtual still images are accessible from the Images group, and can be displayed by selecting an image directly from the list or by selecting an image from the Perseus Image Browser via the Thumbnails button. The image file appears together with the customary image links and the appropriate collection frame (that of "The Bolles Collection on the History of London" in the example of King William Street). Likewise, selecting any of the other virtual reality media, such as "King William Street, London" from the QuickTime panorama group, will display the file with the same familiar format.

The Perseus Web Atlas is able to display the locations of QuickTime environments. Querying a QuickTime location in the atlas will display the virtual reality file using the Perseus standard interface. For more information, see "The Perseus Atlas: Frequently Asked Questions List."

The Perseus Virtual Reality Interface is a graphic interface designed for manipulating the virtual reality content exclusively. The interface employs a custom search tool and "index card" display format to permit the rapid retrieval and switching of different virtual reality presentations of the same subject. The Perseus Virtual Reality Interface also expands the functionality of the Perseus standard interface. In addition to the customary image links to the Perseus Lookup Tool and a thumbnail browser (Browse images), the Perseus Virtual Reality Interface offers a context-sensitive link to related texts (Find related texts). The Perseus Virtual Reality Interface also offers context-sensitive links to Perseus Virtual Reality Help (Help) and the Perseus Web Atlas (Plot Site). Using these links, one can retrieve supplementary information, get appropriate assistance, and plot locations on a world atlas. There is also a context-sensitive link for downloading Computer-Aided Design models and their documentation (Download File).

Collection FAQs:

1. What browsers does the Virtual Reality Collection support?
2. Why can't I see the QuickTime content?
3. Why can't I see the Virtual Reality content?
4. Why can't I see the Drawing Files content?

• Computer Associates International, Inc. CAI's Cosmo Player plug-in provides a very intuitive interface for navigating through a VRML environment. Cosmo Player is cross-platform, although the Macintosh version is officially listed as a "beta" or pre-release version. It works well nonetheless. Cosmo Player supports both Internet Explorer (Windows only) and Netscape Navigator.

  Windows: Internet Explorer version 4.x or later Netscape Navigator version 4.x or later

  Macintosh: Netscape Navigator version 4.04 or later

• Parallel Graphics, Ltd. ParallelGraphic's Cortona plug-in provides a less intuitive interface than Cosmo Player. It takes more time to become comfortable with its navigation tools, which are inconveniently spread out. However, unlike Cosmo Player, Cortona is being actively developed and supported. Cortona is cross-platform, and a version compatible with Macintosh OS X is available. Cortona supports both Internet Explorer and Netscape Navigator.

  Windows: Internet Explorer version 4.0 or later Netscape Navigator version 4.0 or later

  Macintosh: Internet Explorer version 5 or later Netscape Communicator version 4.5 or later

• Autodesk, Inc. Autodesk's Volo View Express* plug-in provides a minimalist interface. Its manipulation tools are only accessible through a pop-up menu, which is displayed by a right-click on the drawing file. Volo View Express only supports Internet Explorer (Windows only).

  Windows: Internet Explorer version 5.01 or later

  Macintosh: Not supported

  *Autodesk has ceased distribution of its free Volo View Express plug-in. Currently, the company only distributes Volo View for purchase.
  
  
• DXF Viewer. DXF Viewer is a free Java program designed to run as a stand-alone application and as an applet (i.e. in your web browser). It only displays wireframe images. And it is only fully compatible with the DXF format up through and including that released with AutoCAD Release 12. DXF Viewer will display files using more recent versions of the DXF format, but parts of the drawing may be missing. Unlike Volo View Express, DXF viewer will run on Macintosh and Linux systems. The DXF Viewer applet runs in both Internet Explorer and Netscape Navigator.

  Windows: Internet Explorer version 5 Netscape Communicator version 4.76

  Macintosh: Netscape Communicator version 4.77

Known Bugs (Virtual Reality Interface Only):

• None at this time.

Using the Search Column (Virtual Reality Interface Only):

The search column appears along the left side of the web page by default. On smaller monitors, the column may be detached from the main page and floated in a separate window. Clicking the gray button in the column's upper left corner toggles between attached and detached states.

Files in the Virtual Reality Collection are retrieved using the search column. Use either the "QuickSearch" menu or the "Search for" box to submit a request to the system. The search results are displayed in the bottom part of the column.

QuickSearch. The "QuickSearch" menu at the top of the column contains a list of countries for which content is available. Selecting a country from the list automatically returns every appropriate file and leaves the current index card active. The "QuickSearch" menu is the easiest method to browse the collection's contents.

Search. To find specific content, first enter the search term(s) in the "Search for" box located below the "QuickSearch" menu and then click the yellow "Find It!" button. When entering multiple terms, use a comma to separate them. For example, enter "Delphi, Rome" not "Delphi Rome" or "Delphi and Rome" in the box. Partial search terms are permissable. For example, entering "Treasury" will return "Athenian Treasury" as a result. Searching by date is not supported within the Virtual Reality Interface at this time. To search for virtual reality content using a specific date, use the Perseus Digital Library's Lookup Tool.

Type. "QuickSearch" and "Search for" results can be limited to a specific format using the "Of this type" radio buttons. By default, a request returns every appropriate file and leaves the current index card active. Selecting a specific type from among the radio buttons limits the returned results to the appropriate format and activates the appropriate index card.

Results. All results are displayed in the bottom part of the column along with a report of the terms and types requested. The results are grouped by type. And if more than three results of a type are returned, the list is truncated to the first three results; the additional results are listed by clicking the appended folder icon. Each result is preceded by a ">>" symbol. A result includes both the name of a file and its unique identifying number. This number can be used as a search term in the "Search for" box. A result also includes the size of a file. Clicking any result activates the appropriate index card and displays the file.

"QuickSearch" and "Search for" requests do more than just return specific results. They trigger behind the scenes operations which establish groups of related "default" files. These are chosen for their commonality with the requests. When different index cards are selected, the appropriate default files are automatically displayed. This allows different formats of the same subject to be explored seamlessly by tabbing through the index cards. And best of all, this feature can be enjoyed without ever having to do anything!

Using the Index Cards (Virtual Reality Interface Only):

The Virtual Reality Interface uses a stack of seven "virtual" index cards to organize its content. A search for any one subject in the search column can return several different types of results. The index cards provide an intuitive way to display and switch between the different types of results, all the while maintaining the entire group of results.

By default, the Virtual Reality Interface opens with the "Start" index card activated. Clicking on the label of any other tab activates that index card, bringing it to the front of the stack. The "Start" and "Help" index cards provide a quick reference to essential information about the Virtual Reality Collection and about the Virtual Reality Interface and how to use it. The remaining index cards display the different types of media: Still Images, QuickTime, Virtual Reality, Drawing Files, and Documentation.

Viewing & Downloading Files (Virtual Reality Interface Only):

Viewing Files. The index cards of the Virtual Reality Interface are initially reactive, that is, they respond to user requests. The cards will not display anything unless a search result appears in the bottom part of the search column. A search result is generated by submitting a request with either of the two methods provided in the search column. Once a request has been submitted, the index cards become proactive and will automatically display a file which has been selected for its commonality with the request. A portion of the Virtual Reality Collection's contents may be browsed by simply conducting a search and tabbing through the different index cards.

To view a specific file, first submit a request for the specific content using the search column. The request returns a list of results which are displayed in the bottom part of the column. From the list, click on the desired file. The appropriate index card is activated and the file is displayed.

If the desired file does not appear in the list of results, it may be contained in an appended folder icon; the folder icon only appears when a request returns more than three files of a particular format. First click on the folder icon to view all of the results for a format. From the expanded list of results, click on the desired file.

Downloading Files. The download feature is only available for source computer models and their documentation. If the "Download File" button does not appear at the top of the index card, select either the "Drawing Files" or "Documentation" tab and be sure that the desired file is displayed. If the "Download File" button at the top of the index card is gray, no file is currently available for download.

To download a file, you must agree to the terms under which it has been made available. First display the file to be downloaded. If a drawing file cannot be displayed because of a plug-in incompatibility, simply be sure that the caption information describes the correct file to be downloaded. Then click on the "Download File" button located in the row of buttons at the top of the index card. In the window that opens, read and agree to the terms; exploitation of the file for commercial purposes is not permitted. To complete the process, click either "Cancel" or "Download."

Viewing Still Images:

These files provide high detail but lack immersive aspects. Because of their minor technological demands, they are the only type which should be browsed by those using dial-up connections and less powerful computers.

Still images of virtual reality content can be displayed using the established methods for viewing images in Perseus. For example, a search by document type using the Perseus Lookup Tool provides a list of the related content contained in the Perseus Digital Library. The virtual still images are accessible from the Images group, and can be displayed by selecting an image directly from the list or by selecting an image from the Perseus Image Browser via the "Thumbnails" button. The image file appears together with the customary collection frame and image links.

The Still Images index card displays both pages of thumbnail images and instances of standard images.

Thumbnail Images. By default, the card displays pages of thumbnail images chosen for their commonality with a request submitted using the search column. The "Your current page" menu at the top of the index card contains a list of the pages which are available. Selecting a new page from the list automatically changes the thumbnail images. It also updates the list of images currently being displayed. Click on any thumbnail image to display an enlarged version of the image; click on "Browse images" to return to the thumbnail display. The pages of thumbnail images are the fastest and most convenient method to browse the contents of the Virtual Reality Collection.

Standard Images. The results of some searches will bypass the default thumbnail pages. If a search returns only one result, and the search was either for a specific file or specifically for the "Still Images" type, the image file will be displayed directly. Similarly, selecting a particular search result will bypass the thumbnail pages and display the image file directly. Once an image is displayed, a variety of tools (links) become available. Using these tools, one can:

• plot the pictured site on a world map,
• find texts in the Perseus Digital Library which mention the pictured object, and
• find other images, art works, etc. in the Perseus Digital Library which are related to the pictured object.

Viewing QuickTime Environments:

The Perseus standard and Virtual Reality interfaces can display QuickTime virtual reality movies, objects, panoramas, and panoramic movies. The QuickTime virtual reality content is a series of still images which have been combined into linear (movie), spherical (object), and cylindrical or cubic (panorama) environments. All three types are "bubbles" in a virtual world. And linked in a network, they create an immersive experience in a virtual world. The QuickTime environments listed among the results from a search using the Perseus Lookup Tool or the Virtual Reality Interface are "gateways" to these larger worlds.

Environment Movement. Movement within an environment is determined by the environment's type:

• Movies. QuickTime movies are animated walk-throughs and fly-throughs of virtual environments. Click the "play" button to start the movie, or drag the "scrub bar" to move forward and backward through the environment.
  
  
• Objects. QuickTime objects present external environments in which the views are directed inward toward a single pivot point. As the lines-of-sight move, the environments appear to rotate. Click and drag within the display to rotate the environment. The direction of the view is indicated on a reference map which, if available, is displayed to the right of the environment. The view may be zoomed in and out using QuickTime's built-in tools. These tools can also be used to move the zoomed view to different areas of the environment. The QuickTime object environment is equivalent to the Virtual Reality "study mode" and the drawing file "orbit tool."
  
  
• Panoramas. QuickTime panoramas present internal environments in which the views are directed outward from a single pivot point. As the lines-of-sight move, the environments appear to spin. Click and drag within the display to spin the environment. The direction of the view is indicated on a reference map which, if available, is displayed to the right of the environment. The view may be zoomed in and out using QuickTime's built-in tools. These tools can also be used to move the zoomed view to different areas of the environment.
  
  
• PanoMovies. QuickTime panoramic movies are hybrids of QuickTime panoramas and movies that mate 360 degree views and video. Like panoramas, panoramic movies present views that are directed outward from a single pivot point; clicking and dragging within the display spins the view. Like movies, panoramic movies are also animated walk-throughs and fly-throughs of virtual environments; clicking the "play" button initiates the animation while dragging the "scrub bar" moves forward or backward along the path through the environment. Views are spinnable while the animation is playing or while it is paused. Depending on the method used to create a panoramic movie, it might be necessary to download an extension to the QuickTime plug-in to view the file.

World Movement. Movement between environments in a virtual world is handled in three ways:

• Menus. The "Your current location" menu above the displayed environment contains a numeric list of all the environments which are available in the virtual world. Selecting a new number from the list automatically moves to the appropriate environment in the virtual world. It also updates any associated reference map.
  
  
• Maps. A reference map, if available, is displayed to the right of the environment. The map is populated with dots. These represent the locations of the environments which are available within the map's scope. Clicking any dot moves to the appropriate environment and updates the reference map. The location of the current environment is indicated by a rotating arrow which simultaneously provides the direction of view.
  
  
• Hot Spots. Links to adjacent environments ("hot spots") are embedded within the environment. When the cursor passes over a hot spot, it changes to a globe and pointing finger. Clicking any hotspot moves to the adjacent environment. It also updates any associated reference map. By default, the hot spots are not visible. However, selecting QuickTime's built-in "Show Hot Spots" tool reveals them.

Virtual Reality Interface Enhancements. By default, the QuickTime index card displays an environment from a virtual world chosen for its commonality with a request submitted using the search column. To display a different world, select a QuickTime environment from those listed among the search results. Once a movie, object, or panorama is displayed, a variety of tools (links) become available. Using these tools, one can:

• plot the pictured site on a world map,
• find texts in the Perseus Digital Library which mention the pictured object, and
• find other images, art works, etc. in the Perseus Digital Library which are related to the pictured object.

Viewing Virtual Reality Worlds:

The Perseus standard and Virtual Reality interfaces can display virtual worlds constructed with the Virtual Reality Modeling Language. These files provide an immersive experience, but are generally less detailed than either the still images or the QuickTime environments.

World Movement. Movement within the virtual world is not restricted except for logical constraints, such as walls and other physical impediments. However, being a virtual world, one may still pass through "solid" objects by turning off collision detection (a preference setting in the browser plug-in). Movement is controlled by the particular software installed. For detailed help with using a particular interface, please refer to the documentation which accompanied the software. While the various software interfaces differ in appearance, their controls offer the same options for movement:

• Walk Mode. Walk mode applies gravity to the virtual world. It restricts movement to surfaces as would normally be experienced in the real world. This mode facilitates a "real-world" understanding of the physical relationships between different objects in the virtual world. For example, in a reconstructed site, walk mode ensures that proper sight-lines are maintained during movement.
  
  
• Fly Mode. Fly mode removes gravity from the virtual world. It allows free movement throughout the virtual world. This mode facilitates a broader understanding of the physical relationships between different objects in the virtual world. For example, in a reconstructed site, fly mode permits bird's-eye views that demonstrate relationships between distant structures that would otherwise be obscured by line-of-sight issues in walk mode.
  
  
• Study Mode. Study mode restricts movement to a sphere around a single pivot point, toward which the view is fixed. This mode facilitates the examination of particular objects in the virtual world. It is equivalent to the QuickTime "object" environment and the drawing file "orbit tool."
  
  
• Extra Tools. Customarily, the software interfaces provide other useful tools for moving to preset locations, moving to locations of user interest, and righting a view which has become disoriented.

Virtual Reality Interface Enhancements. By default, the Virtual Reality index card displays a virtual world chosen for its commonality with a request submitted using the search column. To display a different world, select another from those listed among the Virtual Reality search results. Once a virtual world is displayed, a variety of tools (links) become available. Using these tools, one can:

• plot the pictured site on a world map,
• find texts in the Perseus Digital Library which mention the pictured object, and
• find other images, art works, etc. in the Perseus Digital Library which are related to the pictured object.

Viewing Computer-Aided Design Models:

The Perseus standard and Virtual Reality interfaces can display the source computer models used to produce the image, QuickTime, and Virtual Reality content of the Virtual Reality Collection. These source models provide graphic databases of size, shape, location, orientation, and more.

Model Manipulation. The CAD drawing files may be manipulated online using any web-enabled file viewer capable of displaying DXF type files. Currently, the most fully featured software is only available for Windows-based computers. To view the drawing files on other systems, use DXF Viewer or download the file and then open it with any commercial drafting program compatible with the DXF format. File manipulation is controlled by the particular software installed. For detailed help with using a particular interface, please refer to the documentation which accompanied the software. While the various software interfaces differ in appearance, most offer the same basic tools for manipulation. In the case of Autodesk's Volo View Express, these tools are contained in a pop-up menu displayed with a right-click on the drawing file.

• Pan Tool. A pan tool moves the drawing file up, down, left, and right in the plane of the monitor.
  
  
• Zoom Tool. A zoom tool moves in and out from the plane of the monitor, effectively moving closer to and farther from the model.
  
  
• Orbit Tool. An orbit tool restricts movement to a sphere around a single pivot point, toward which the view is fixed. While in the orbit mode, Volo View Express provides shading and perspective options in a right-click pop-up menu. The orbit tool is equivalent to the QuickTime "object" environment and the Virtual Reality "study mode."
  
  
• Layers Tool. A layers palette allows different parts of a model to be displayed or hidden from view.

To fully exploit the drawing files, the files must be downloaded and then opened with a commercial drafting program compatible with the DXF format. The models can then be mined for data, modified, and otherwise used to meet user-specific needs.

Virtual Reality Interface Enhancements. By default, the Drawing Files index card displays a drawing file chosen for its commonality with a request submitted using the search column. To display a different drawing file, select another from those listed among the Drawing Files search results. Once a drawing file is displayed, a variety of tools (links) become available. Using these tools, one can:

• plot the pictured site on a world map,
• find texts in the Perseus Digital Library which mention the pictured object, and
• find other images, art works, etc. in the Perseus Digital Library which are related to the pictured object.

Viewing Documentation:

The Documentation index card of the Virtual Reality Interface displays files which appropriately detail the sources and processes used to create the models shown on the Drawing Files index card. Inevitably, the creation of a model requires multiple sources. The document files are a record of these sources and the parts modeled after them. The document files are also a record of the parts modeled purely on educated guesswork. This documentation is provided to support the academic validity of each model. It is also provided to maintain a model's overall integrity if one or another element is proven to be incorrect.

By default, the Documentation index card displays information relevant to the image, QuickTime, Virtual Reality and drawing files automatically chosen for their commonality with a request submitted using the search column. To display a different document file, select another from those listed among the Documentation search results. Once a document is displayed, a variety of tools (links) become available. Using these tools, one can:

• plot the relevant site on a world map,
• find texts in the Perseus Digital Library which mention the relevant object, and
• find other images, art works, etc. in the Perseus Digital Library which are related to the relevant object.