Re: Standardized Application Level Information in VRML files

[Martin Reddy <reddy>]

Martin Mauve said, on www-vrml@vrml.org:
> My question is therefore: Are there mechanisms wich allows applications to
> include application level information in VRML files in a STANDARDIZED way?
> If no, does anyone out there think that this might be an important
> functionality which should be further investigated?

I agree that there is a definite need to be able to incorporate application
level information in your VRML definitions. Many people use VRML as a means
to an end - to display 3D graphics over the web, but there are also many
people who would like to be able to use VRML as an interchange format - a
format to write the 3D data for a particular application so that it is also
available to anyone with a VRML browser.

We have been developing a terrain visualisation utility for some time and
now wish to have the terrain data available in VRML. We faced similar
problems that you mention in that we need to represent a richer, application
specific dataset than VRML allows (simply because VRML is a generic 3D
language, as of course it must be). We overcame this be defining new nodes
via the EXTERNPROTO facility. This way you can include hooks for information
in the PROTO interface that your specific application requires, but will be
ignored by a standard VRML browser.

As for a standardised way of doing this, I tend to agree with Vladimir that
it may not be possible to find a completely generic way of representing
arbitrary application-level data - it is after all specific to a particular
application package or area and may not be of relevance out with that
domain. In our case, Lee Iverson here has recently started the GeoVRML
Working Group which aims to look at how we can incorporate geo-referenced or
cartographic models into VRML in a standardised way so that people working
in the area and using VRML will be able to interchange data.

Hope this helps,

Martin.


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Martin Reddy                                   SRI International, AI Center
                                               Menlo Park, CA 94025-3493
reddy@ai.sri.com                               Tel : (650) 859-6468
http://www.ai.sri.com/~reddy                   Fax : (650) 859-3735