1/6/2004 

It is recommended that this world be viewed with either Parallelgraphics, Inc.'s Cortona viewer or CA, Inc.'s CosmoPlayer.  The native Microsoft Internet Explorer 6.0 VRML player does not render graphics with sufficient resolution to support this application.  

This application will not run under Blaxxun Contact VRML player.  This application has not been tested against the native Microsoft Internet Explorer 6.0 VRML plug-in. 

As of the date of this install file, valid urls to obtain either the Cortona or CosmoPlayer plug-ins are: 

Cortona		http://www.parallelgraphics.com/products/cortona/ 
CosmoPlayer	http://ca.com/cosmo/ 

Of the two recommended viewers,  Cortona is preferred for use with this application. It was used as the primary VRML player during development of this application. 

When unzipping this world,  subdirectories may be translated by the zipping and unzipping packages on some systems into upper-case capitals, e.g. 'lib' -> 'LIB'.  

For best compatability,  rename these directories to lowercase, e.g. 'lib', 'refer', 'data', etc.  

Some VRML viewers require case sensitive directory names inorder to locate the resource file, e.g. CosmoPlayer 

This plotting application has been tested for compatability with Cortona Player and CosmoPlayer.  Cortona Player was the primary development environment.  

This plotting application was developed and tested on a 1.8 mhz PC using the Microsoft Windows operation system.  The application has been loaded on older Windows 98 systems with processor speeds as low as 100 mhz and no graphics-card acceleration of rendering, but the load time is approximately 1 minute.  After loading, the application response time was acceptable but sluggish.  

Known bugs:  

1.0 Applicable to all VRML players: 

	1.1)  Occasionally,  an onload error will occur under Cortona and CosmoPlayer.   Always try one reload "refresh".   This usually is a file transmission error. 

	1.2)  When clicking on world objects that have an anchor action, the default behavior is to search first for a url link describing the object.  If no object reference page has been created, the viewer should cascade to a second default url for a "Not implemented" page.  Although this functions when worlds are started on local drives, apparently the cascading anchors do not work when the application is distributed over the internet. Therefore, a standard "page not found" error will occur.   Recover with the browser "back" button. 

	1.3)  When using the origin viewpoints, rotation of the world slightly off-center. 

	1.4)  When viewing from the latitude -30 and -60 viewpoints,  the "up" orientation is not correct.  It is a compromise to be consistent with a northern hemisphere biased view from the latitude +20 and equator viewpoints. 

2.0 Unique to CosmoPlayer. CosmoPlayer will not express all features, described as follows: 

	2.1)  In CosmoPlayer, the background color switching option group does not work properly.  Remain in the initial "white" background.  The background option group is functional, but reverts to the next to last selected state when a new viewpoint is selected.  To use the background switcher in CosmoPlayer,  (1) select the desired color,  (2) then select a new color, and (3) finally select a viewpoint.  The player will revert to the next to last selected color - in this case the desired color.  After trying three different programming approaches,  it was concluded that this runtime problem is inherent to the way that CosmoPlayer binds the color to the current viewpoint.  The programming approach adopted here was the best of three undesirable alternatives.  This feature functions properly under Cortona. 

	2.2)   The display mode of this world is not locked in "Examine," in order to allow the user to fully explore data in 3 dimensions.   When placed in "Examine" mode,  Cortona correctly binds to the origin of the axes as the center of the world (per a VRML "center" directive).  CosmoPlayer binds to the end of the postive X-axis as the center of the world, instead of the origin.  Recover by tilting the model to expose the origin of the axes.   Use CosmoPlayer's "seek" command to correctly bind the examination center of the world to the origin.  It is believed that this bug may be resolvable by syntax changes. 

	2.3)  With Netscape Navigator 7.0 and  CosmoPlayer,  the first viewpoint labelled "x-y slice" occassionally will display about 1 world unit closer than its setting.   This is an unresolved runtime error that does not occur under Cortona player. 

	2.4)  With Netscape Navigator 7.0 and  CosmoPlayer,  the world does not load as local file using the "File | Open" option.  It does operate normally when loaded across the internet.  

Warnings: 

1.0 Generally, both Cortona's and CosmoPlayer's ability to display graphics and retrieve files seems to be adversely effected by Real One Player running in the background under MS Windows.  To recover the VRML display within a web browser, it may be necessary to reboot MS Windows machines to totally remove Real One from the processor stack.

