[ODE] XODE trimesh structure - please vote

[William Denniss]

On Wed, 2004-03-17 at 03:30, Jon Watte wrote:
> > And because it is only meant as an interchange format I think the advantages 
> > of XPath and XSLT outweigh the disadvantages of slower parsing and larger 
> > filesize.
> 
> I think this is the real question. Is this a format that can
> conceivably be used for real storage, or is it specifically designed
> to be as slow as possible to ease obscure interchange cases? If so,
> what, specifically, are those concrete interchange cases?

While the primary goal is interchange, I think a secondary goal should
be for real storage.  As Roel mentioned before, a gzipping XODE file
will pretty much be the same size be it using #1 or #2 (for a large
trimesh).  XML by nature will have a low entropy due to the repetition
of the tags so the cost of even an unabbreviated <vertex> tag is little
after compression.

> I'm not very interested in an interchange format that's not useful for
> actual work. Thus, my vote is for comma-separated, and I don't care
> about extra attributes (I can stuff per-triangle friction and whatnot
> in a separate element). I don't see XSLT transform as particularly
> relevant to the common-case use of these files.
> 
> If it's all interchange, then I don't care (though I still don't see
> XSLT transforms actually being used :-).

The main advantage of XML it seems is XSLT and the disadvantage is the
alleged slowness in parsing and larger file sizes.  Larger file sizes
can be dealt with using compression.  How much slower would the parsing
be using #2 rather than #1?  If this is the most important issue then we
will have to benchmark it - else we are just stabbing in the dark.

We need to evaluate just how useful XSLT transforms are.  I did a bit of
digging as I haven't had much experience with them and it seems that
they could be extremely useful in conversions.  XODE to binary seems a
possibility, or even going the other way say converting a X3D mesh into
an XODE trimesh.

It seems XSLT could avoid the need for coding a converter entirely -
that is a big plus in my book.


Heres some random links that I turned up from my search:

Finding the Fit for XSLT - Filling a hole in the puzzle
http://www.sys-con.com/xml/articleprint.cfm?id=763

Binary Killed the XML Star?
http://www.xmlmania.com/documents_article_112-Binary-Killed-the-XML-Star-.php

Binary XML, Again
http://www.xml.com/pub/a/2003/08/13/deviant.html


Cheers,

Will.

-- 
William Denniss - will@ http://tanksoftware.com/