Re: [Algorithms] Bicubic normals for a bicubic world

[John S. <jse...@ho...>]

Ok, maybe reducing it to 2D wasn't such a good idea.

What we really want is a curve that descibes the surface normal of a bicubic
surface. This normal is the cross product of two tangents, one in u and one
in v. Each of these tangent surfaces is a partial derivative, so while it's
a quadratic in one parameter, it's a still cubic in the other.

If you can fit that into a biquadratic surface, I'd like to see it, 'cause I
can sure use it! ;-)

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: "Tom Forsyth" <to...@mu...>
To: <gda...@li...>
Sent: Thursday, August 10, 2000 9:55 AM
Subject: RE: [Algorithms] Bicubic normals for a bicubic world


> No - in the S shape, each component of the normal goes from value A to
value
> B and back to value A, which can be described by a quadratic.
>
> Tom Forsyth - Muckyfoot bloke.
> Whizzing and pasting and pooting through the day.
>