Re: [Algorithms] Bicubic normals for a bicubic world

[Conor S. <cs...@tp...>]

As I said - In both directions. Not that hard.

> How are the normals biquadratic? And the two tangent surfaces can't be
> biquadratic, because you're only derivating in one parameter, leaving the
> other as-is. You derive in u, it's still cubic in v, and vice-versa.
>
> I really want to have a good solution to this, so please bear with me.
>
> Thanks.
>
> John Sensebe
> jse...@ho...
> Quantum mechanics is God's way of ensuring that we never really know
what's
> going on.
>
> Check out http://members.home.com/jsensebe to see prophecies for the
coming
> Millennium!
>
>
> ----- Original Message -----
> From: "Conor Stokes" <cs...@tp...>
> To: <gda...@li...>
> Sent: Friday, August 11, 2000 9:58 PM
> Subject: Re: [Algorithms] Bicubic normals for a bicubic world
>
>
> >     Actually, if you think about it - The normals are totally quadratic.
> And
> > if you do a derivitive in 2
> > directions (across S, and across T) you do get 2 quadratics. Not only
> that,
> > the cross product is
> > resiliant to transforms - So it remains the same. However, normalisation
> > still needs to occur.
> >
> >     This is why I precalc my normals and reference them from a map in
most
> > cases.
> >
> > Conor Stokes
> >
> >
>
>
>
> _______________________________________________
> GDAlgorithms-list mailing list
> GDA...@li...
> http://lists.sourceforge.net/mailman/listinfo/gdalgorithms-list
>