Path: chuka.playstation.co.uk!news
From: "Peter Dollochan" <Peter.Dollochan@btinternet.com>
Newsgroups: scee.yaroze.freetalk.english
Subject: Re: Triangles, Quads???
Date: 14 Oct 1998 17:57:30 GMT
Organization: PlayStation Net Yaroze (SCEE)
Lines: 68
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References: <362238AE.DF3414FF@usa.net> <36228105.D38787F2@datasys.net> <3622FF14.B0A6AA9D@hinge.mistral.co.uk> <3624E1B7.DB009494@usa.net>
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Doesn't the Sony tool DXF2RSD.exe do just that with one of its
parameters -QUAD sounds about right. I think this alters the vertex
data instead of adding points.......

Of course I could be talking rubbish....

Pete.


K.Wutzke <kwutzke@usa.net> wrote in article <3624E1B7.DB009494@usa.net>...
> 
> 
> Craig Graham wrote:
> 
> > Darco wrote:
> >
> > > The playstation intreprets a quad as 2 triangles. (I know this is
true
> > > because I've got the numbering wrong on a quad many times, and the
GPU
> > > renders 2 distinct triangles) Look at this rough sketch. (If it
doesn't
> > > look right, look at it with a fixed size font)
> > >
> > >         0------1
> > >         |     /|
> > >         |    / |
> > >         |   /  |
> > >         |  /   |
> > >         | /    |
> > >         |/     |
> > >         2------3
> > >
> > > Because it does this, it really doesn't matter which you choose. If
> > > there is a speed difference it will be minimal. However, the data for
2
> > > triangles is larger than 1 quad. So if you are dealing with large
> > > models, it may be more efficient to use quads rather than triangles.
> >
> > A quad should be faster than 2 triangles because the gte only has to do
> > 4vertex transformations instead of 6 (2 of the vertices are common
between
> > the two triangles). It's the same reason that mesh lists are faster on
> > Direct3D
> > (less calculations per polygon).
> >
> > NOTE: The GPU is much faster than the gte. You can render more
triangles
> > than you
> > can calculate, so any reduction in calculation is a benefit.
> >
> > > 'Darco
> >
> > Craig.
> 
>   re there any modelers/tools that can optimize an output model for
quads?
> I don't want it to "expand" (quadrangulate) the tris to quads (add a
vertex),
> but instead find almost coplanar, adjacent triangles and make these a
quad,
> accepting minimal vertex position corrections.
> Any suggestions? Or will I have to write my one tool? Hnnngh... :-(
> What can 3D Studio MAX R2 do for that?
> 
> Karsten
> 
>