Re: [www-vrml] VRML still the most popular Web3D format - by far.

["George Birbilis" <birbilis@kagi.com>]

> Which, from where I'm sitting, makes "Extensible" 3D less extensible
> than VRML97. Because I'm interested in a spec that will enable an
> extensible implementation. VRML97 enables an implementation that can be
> extended by plugins--written by users--which can be referred to with a
> browser-agnostic syntax; thus enabling content that can scale to various
> browsers. I do not see how X3D enables that approach; and (consequently)
> I also see no mapping for VRML97 content that takes advantage of it.

The only problem I see is that as it is now, it forces the browser to have a
hardcoded URL to a central repository maintained by the browser maker (or
maybe by Web3D in the future if X3D browsers agree to some common code
extensibility format). There seems to be no way to refer to extensions using
a URL inside the X3D document.

This has both bad and good things:
[1] bad is that the browser extensibility repository server may be a
bottleneck
[2] bad cause the browser company may change URL (bought by other company
etc.) for their update server
[3] bad cause the browser company may die and so their server in the future
--- note [2] and [3] can be partially solved by having an option in browser
settings to use another repository server (NOT have such option though IN
the X3D document)
[4] good cause you don't need ANY trust model (signed code etc.) like you
have in ActiveX controls and signed Java applets for the extensions. Since
the document can't directly refer to remote code, but only mention a
profile+components to use that the browser itself uses as keys for a search
for extensions at the repository it is already set to use, it's sure the
extensions are safe (they can be signed if extra safety is needed for
not-being tampered on the fly while being transmitted or by the use of fake
servers, else some partial safety is provided by SSL connection to the
upgrade server [prefer the code signing] - problem with signing is that the
browser should allow at its options to set one or more trusted publishers'
certificates to use for checking browser extensions, useful if one wants to
allow changing the repository server and allow a company to make custom
plugins etc.)

regarding the EXTERNPROTO used for browser extensions, I think it was mostly
useful to parsers to check the "validity" of a document, not to browsers,
since it had the definition of new nodes, but not their implementation. I
wonder how XML + schemas work though if you don't have that and just mention
a "component" (unless the component is used as a key to make some URL of the
style http://www.web3d.org/schemas/x3d/?<component> to refer to a schema)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
George Birbilis <birbilis@kagi.com>
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ QuickTime VCL and ActiveX controls (for PowerPoint/VB/Delphi etc.)
+ Plugs VCL and ActiveX controls (InterProcess/Internet communication)
+ TransFormations, VB6 forms to ASP.net WebForms convertion
http://www.kagi.com/birbilis
+ Robotics
http://www.mech.upatras.gr/~robgroup
........................................................................

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