Invisible <voi### [at] devnull> wrote:
> Tor Olav Kristensen wrote:
>
> > I just posted this:
> >
> >
http://news.povray.org/povray.binaries.scene-files/thread/%3Cweb.4c327e199f459e99c734aecd0%40news.povray.org%3E/
>
> /*
> // If you now limit the ranges that these variables defines,
> // then only a part of the surface will be "meshyfied".
> // (If you expand these ranges, you'll get an error.)
> #declare MinUV = <0.2, 0.0>;
> #declare MaxUV = <0.8, 0.9>;
> // U will wary from 0.2 to 0.8
> // V will wary from 0.0 to 0.9
> */
>
> U will "wary"?
>
> What are you, Elmer Fudd?
>
> Sorry, that just amused me...

=)

> Anyway, I'm still wading through the NURBS code. Damn this looks
> complicated!

Yes, I too find NURBS a bit complicated. Just take small steps and try to code,
draw and experiment with every little new idea in books and web pages about
NURBS.

Btw.: I hope you are looking at the code in the attached file: NURBS_28_.inc and
not the code you quoted above.

I recommend that you go through these macros (in the listed order) within that
file:

UniformKnotVector(Open, Order, NrOfPoints)
Cox_deBoor(Order, Knots, K)
BlendFunction(Order, Knots, K)
BlendFunctions(Nr, Order, Knots)

NURBS_Function1A(OrderU, KnotsU, Values1A, Weights1A)
ExtractComponent1A(Vectors1A, v0)
ShowFunctions1A3D(xFn, yFn, zFn, WrapU, MinU, MaxU, ResU, Radius)
Show_URBS_1A3D(Points1A3D, Weights1A, OpenU, OrderU, WrapU, DivU, Radius)

NURBS_Function2A(OrderUV, KnotsU, KnotsV, Values2A, Weights2A)
ExtractComponent2A(Vectors2A, v0)
ShowFunctions2A3D(xFn, yFn, zFn, WrapUV, MinUV, MaxUV, DivUV, ResUV, Radius)
Show_URBS_2A3D(Points2A3D, Weights2A, OpenUV, OrderUV, WrapUV, DivUV, ResUV,
Radius)

--
Tor Olav
http://subcube.com

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