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<P>Nieminen Mika wrote:
<BLOCKQUOTE TYPE=CITE>JK <kla### [at] hotmail com> wrote:
<BR>: What do you want this 'parabola' object to look like exactly? I've
noticed that
<BR>: there are (almost) always several ways to solve a problem in POV
script, so the
<BR>: description parabola object isn't sufficient for me to think of something
here
<BR>: right away.Can't you be a bit more specific?
<P> I think that what he means is a paraboloid, which can be defined
with the
<BR>function f(x,y)=x^2+y^2
<BR> This can be easyly achieved in povray with the poly object.
<P>--
<BR>
- Warp. -</BLOCKQUOTE>
THE WONDERS OF THE POVRAY DOCUMENTATION
<BR>Lesson 1
<BR>by JK
<P>7.5.4.3 Quadric
<P>Quadric surfaces can produce shapes like ellipsoids, spheres, cones,
cylinders, PARABOLOIDS (dish shapes) and hyperboloids (saddle or hourglass
shapes). Note that you do not confuse quaDRic with quaRTic. A quadric is
a 2nd order polynomial while a quartic is 4th order. Quadrics render much
faster and are less error-prone.
<P>A quadric is defined in POV-Ray by
<BR>
<P> quadric { <A,B,C>, <D,E,F>, <G,H,I>, J }
<BR>
<P>where A through J are float expressions that define a surface of x,
y, z points which satisfy the equation
<BR>
<P> A x^2 + B y^2 + C z^2 +
<BR> D xy + E xz + F yz +
<BR> G x + H y +
I z + J = 0
<P>.....
<BR>and so on.
<BR>It's all there. Don't think too much on the math, just begin.
<BR>Yesyes, you're welcome.
<P>JK
<BR>--
<BR> <A HREF="http://surf.to/jkhome">Visit my newly updated homepage!</A></HTML>
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