Path: chuka.playstation.co.uk!news From: "K.Wutzke" Newsgroups: scee.yaroze.freetalk.english Subject: Re: Triangles, Quads??? Date: Wed, 14 Oct 1998 19:39:03 +0200 Organization: PlayStation Net Yaroze (SCEE) Lines: 48 Message-ID: <3624E1B7.DB009494@usa.net> References: <362238AE.DF3414FF@usa.net> <36228105.D38787F2@datasys.net> <3622FF14.B0A6AA9D@hinge.mistral.co.uk> NNTP-Posting-Host: dialup7-36.access.nacamar.de Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 4.05 [en] (Win95; I) 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