Subject:
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Re: Crazy, OK Heretical Idea ...
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Newsgroups:
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lugnet.cad
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Date:
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Mon, 28 Apr 2003 04:13:54 GMT
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Viewed:
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764 times
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Wayne Gramlich wrote:
> Jason:
>
> There are lots of 3D formats out there; some proprietary, some
> semi-proprietary, and some completely open. Besides the 3D game
> folks, there are the 3D art programs (e.g. 3D Studio Max) and
> the 3D CAD/CAM folks (e.g. AutoCAD.) Each area has a plethora
> of 3D formats.
Yep. I've actually written code to convert between several of these and
they don't really fit the bill : ( The ones that are commonly used are
proprietary and these kinds of programs typically need workstation-level
computing power to work with anything complex enough to be really
interesting. (Did I mention that I loathe AutoCad ?) The game formats
are designed for good perfomance with current generation consumer-level
hardware. Game companies didn't design the formats and the tools to use
them because they wanted to pay their coders more money while
re-inventing the wheel... They did it because nothing else got the job done.
> I'm unconvinced that the current LDRAW format needs to be
> replaced; however, there is nothing wrong with becoming familiar
> with alternative 3D formats to grab ideas for LDRAW format
> extensions.
We need vertex lists very badly. Current Ldraw renderers pay at least a
3x speed penalty right now because they have to apply a translation
matrix to the same point in each of the polygons that intersect at that
point. (Unless they're doing some caching, or converting to an internal
representation that uses vertex lists, but neither is ideal) Tweaking
the format a little bit would save those duplicate calculations. Once we
have vertex lists we can simply send them, the polygons, textures, and
the transformation matrices directly to the graphics hardware to chew on
(aka OpenGL and Cg)
> I would recommend looking at VRML first; it is one of the cleaner
> 3D formats out there, with several books published on the topic.
> It is frequently possible to borrow one of the VRML books via inter
> library loan (ask your local librarian about ILL), rather than
> having to outright purchase it. For a variety of reasons, VRML
> never really connected in the marketplace, though.
Yeah, it should have taken off years ago : (
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Message has 2 Replies:
 | | Re: Crazy, OK Heretical Idea ...
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| (...) LOL, that's kind of like saying, "Did I mention that I loathe Microsoft?" (Hmmm... You probably say that too..) AutoCAD is the 300lb gorilla of CAD. (...) Of course you're correct. But keep in mind CAD software was written to do a specific job (...) (22 years ago, 28-Apr-03, to lugnet.cad)
| | | Re: Crazy, OK Heretical Idea ...
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| (...) You might look into the LDLite language extensions -- they probably don't qualify as true vertex lists, but they do allow you to write files in a vertex-list friendly fashion. You can use the POINT meta-statement to define each vertex at the (...) (22 years ago, 1-May-03, to lugnet.cad)
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Message is in Reply To:
| | Re: Crazy, OK Heretical Idea ...
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| (...) Jason: There are lots of 3D formats out there; some proprietary, some semi-proprietary, and some completely open. Besides the 3D game folks, there are the 3D art programs (e.g. 3D Studio Max) and the 3D CAD/CAM folks (e.g. AutoCAD.) Each area (...) (22 years ago, 27-Apr-03, to lugnet.cad)
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