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On January 31 2005 at 16:29:21 EST Bullard, Claude L (Len) <email@example.com> wrote:
> Slightly orthogonal, yes, but to demonstrate that even the data head
> vs document head perspectives on XML leave out what can
> be done with XML, so one should be very wary of best
> practices without understanding the underlying model of
> the application. VRML had a way of exposing my preconceived
> notions from SGML as the humbugs they were. The X3D
> experience, even moreso, since in that, the assumptions
> of XML and XSD got pushed to the edge. Real time object
> models are not really documents or data in the way many
> think about those things. X3D is a modeling language
> and a real time animation rendering. The advantages
> to that from XML are not *as* great as one suspects,
> and there are some penalties. There are benefits,
> but again, not nearly as many as in transactions,
> serialized documents, data base export/imports, etc.
> In interchange applications, ummm... ok some but mainly
> the same: no new parse, some validation, good db tools,
> quick and dirty editors (not really good ones either
> because modeling is interactive graphics modeling and
> the XML generic tree editors aren't the best approach).
> So XML for graphics is a good thing, but no magic and less juju.
> Tim Bray said it best when X3D was getting started: get
> the object model right first. The markup model is
> trivial after that.
> But tossing in the best practices without knowing the
> object model? That won't be trivial at all, and in fact,
> can lead to some really ugly designs. Keep in mind
> WHY you use XML and optimize for that.
> From: Jeff Rafter [mailto:firstname.lastname@example.org]
> > OTOH, since ROUTEs are from DEF names to DEF names, USEd
> > objects can get you in trouble. If for example, you
> > send a transform to the rotation field, all of the
> > USE'd objects spin.
> In SVG this is roughly similar-- but in general because of the box model
> the rotations are cumulative-- so you can rotate a rotation without much
> penalty. Where things get sticky in SVG is calculating out the CSS
> inheritance and selectors. Applying textures maybe similar-- but
> multiply that against all of the possible CSS properties and you don't
> end up saving much time with regard to performance. To be fair to
> Roger's original post, this is a slightly orthogonal tangent... it is
> just a real world example where an id/idref mechanism isn't all it is
> cracked up to be. Or in Len's case, is a far better approach.
> Jeff Rafter
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