Re: [Algorithms] VIPM and UV texturing

[Mark W. <mwa...@to...>]

Now this sounds like a cool idea :)

Mark

----- Original Message -----
From: "Tom Forsyth" <to...@mu...>
To: <gda...@li...>
Sent: Thursday, August 10, 2000 3:32 AM
Subject: RE: [Algorithms] VIPM and UV texturing


> This is also solved if you start with a low-poly mesh from the artists,
> tesselate and displace up to a high-poly mesh, then VIPM down again, but
> preserving the original edges. Because the tesselation only uses linear
> interpolation for non-geometry attributes, you don't have to deal with
nasty
> cases like this. Fortunately, coz they are a real pain.
>
> http://www.muckyfoot.com/downloads/tom.shtml
>
> Tom Forsyth - Muckyfoot bloke.
> Whizzing and pasting and pooting through the day.
>
> > -----Original Message-----
> > From: Jeff Lander [mailto:je...@di...]
> > Sent: 09 August 2000 18:06
> > To: gda...@li...
> > Subject: Re: [Algorithms] VIPM and UV texturing
> >
> >
> > Hi all.  New to this discussion but I have recently had a
> > couple of projects where this issue has been very important.
> >
> > The issue you bring up about texture coordinates and any sort
> > of mesh LOD system is critical.  That is why I insist that
> > the LOD tools allow artists to hand designate edges that will
> > not collapse.  Any algorithmic method you try and find will
> > fail in certain cases.  The algorithms handle texture
> > projections like sphere and cylinder wraps pretty well but
> > arbitrary UV texturing is a real problem.
> >
> > One particular problem I will share that comes up often is
> > when texturing characters.  My system automatically will
> > preserve vertices that have texture coordinate
> > discontinuities.  However, artists will often model a
> > character with only half of the texture (particularly in the
> > face) then just reflect the texture coords to save texture space.
> >
> > Now the problem as you would guess is you have the face with
> > coordinates like (1,0) -----  (0,0) ---- (1,0).  Obviously
> > more granular then that. There are no texture coordinate
> > discontinuities so the algorithm says it is ok.  The surface
> > of the face is roughly flat so the internal vertex and edges
> > are good candidates for collapse.  However, you then get the
> > nice situation of  (1,0) ------ (1,0).  Doesn't look so hot.
> > I have the artists tag reflected seam vertices as
> > uncollapsable until very late in the order.
> >
> > Let me paraphrase you by saying the algorithms are most
> > efficient when working on trivially textured objects.
> > Anything else requires good artist tools and some TLC.
> >
> > -Jeff
>
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