Re: 3d file type

["Stephen J Baker" <sjbaker@link.com>]

On Wed, 13 Nov 2002, Chris wrote:

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> [Tue, 12 Nov 2002 22:09:34 -0600] Message from Steve Baker:
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> > The 'MODELLER FORMAT' will probably be something like '.obj' *UNLESS*
> > you are lucky enough to own a modeller that supports file I/O
> > plugins - in which case, you would probably be well advised to write
> > an 'exporter' for a format that holds exactly the information you need
> > as input to your 'model compiler' - and yet is easy to read and write
> > so as not to slow down your modelling process.
>
> I agree with everything you say except this paragraph. If your models are
> fairly simple, and the modeller supports the features you need just in a
> different way than you need in the game, then exporter plugins are fine.
> But if you need to include a lot of game-specific information then exporters
> may actually make life more complicated.

If you need to CREATE the game-specific information in your modeller
then you probably NEED a custom exporter because that game-specific
information won't be held in a convenient form in any of the standard
file formats.  That's especially true if the modeller itself has
a plugin architecture.  Your modelling plugins may create data that
the standard file formats don't capture - then you need file I/O
plugins too.

However, I don't disagree with you if all of this game-specific stuff
can be created or merged with the 3D model in your 'compiler' that
converts modeller-format into game-format.

> To illustrate this, the models in my game can have up to three different
> "layers"...
<snip>
> ...and a load of other information. Now I could write an exporter for a modeler
> that generates some of this, but I absolutely need a tool to define the
> rest - and if I change the game format then I not only have to recompile
> bits of the custom tool but also the exporter and make sure everyone using
> the exporter has updated both the tool and the exporter to the latest
> versions.

I don't disagree.  If you can 'define the rest' of the information you
need in an external tool - then that's good news.  That code can reside
in the MODELLER->GAME compiler and you can use a standard file format
for the MODELLER format.

> However, by keeping all the format loading in the tool only the
> game format reader and writer in the tool need be updated. Harsh experience
> has taught me that keeping the number of things people need to update to
> a minimum is the only way to avoid minor disasters each time you change the
> file format..

Yes - but there are times where you can specify data in the modeller
(eg: via plugins) that doesn't get exported via the standard file I/O
mechanisms of the modeller - then you have no choice.

----
Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
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