Re: PHIL: User Customization (Was: Looking for Linux based VRML tools)

Brian Behlendorf ([email protected])
Sun, 9 Apr 1995 20:55:35 -0800 (PST)


On Sat, 8 Apr 1995, Peter J. McCann wrote:
> VRML presents a unique opportunity to decouple the (user-defined) view
> (rendering) of an object from its underlying logical (author-defined)
> structure. If my browser encounters an object of type 'foo', I should
> have a choice over how 'foo' is rendered, even though there might be
> some default or widely accepted standard.

There is definitely a desire for this type of functionality - for
example, a scene representing a kitchen might want to position and place
a bounding-box around an object called "refrigerator", and I as the
browser may decide that I have a perfectly good model of a refrigerator
here locally, so I decide not to fetch the remote object. This isn't in
1.0, but it's probably a good candidate for being described in 1.1 or 2.0.

> VRML represents 3D scenes as trees or DAGs that have structure. This is
> a big win over a markup language that simply annotates some existing
> structure. Personally, I wouldn't mind seeing other types of documents
> written in a VRML-like syntax, such as:
>
> #VRML V2.0 ASCII
> TextDocument {
> Title {
> title "My Logical Document"
> }
> Preface {
> body "Welcome to my logical document...
> ...
> "
> }
> Introduction {
> }
> Chapter {
> chapnum 1
> body "Hello there..."
> }
> Chapter {
> chapnum 2
> body "Hi there again..."
> }
> }
>
> This would greatly facilitate searches and indexing, and would also allow
> me to "render" the document the way I want to see it, at any of several levels
> of abstraction.

Hello, you've just perfectly described what SGML is all about :) Well
written HTML or SGML documents are indeed really trees. I.e.


My Logical Document

Welcome to my logical document...

Hello there...
Hi there again...

represents (In HTML 3.0) just about exactly the same thing. Many sites
with large numbers of documents keep them in their own SGML DTD and
downconvert to HTML at the server-level, thus defining their own tags
with their own semantic meaning.

But tying this back in with VRML - while conceptually similar the
decision was made that we're not really describing markup but something
more like Postscript, though hopefully since it's hierarchical we can
build in constructs for semantic capabilities that will allow us to
describe a scene like the kitchen described above.

Brian

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