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Are there any pages out there that show actual comparison of the various
ways of making a curve from a set of points?
I'm interested in making something with tenacles, and I just don't like the
way the quadratic, cubic, and natural splines look with a set of points--
it just bends-- more of a kink-- too much for something like an octopus'
leg or a mechanical tenacle.
I've seen pages for the hermite curve, but it really didn't have an adequate
visual demonstration of why one ought to go to the trouble of using it.
Greg M. Johnson
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news:web.4009c6d4976554543a5fb9ba0@news.povray.org...
> Are there any pages out there that show actual comparison of the various
> ways of making a curve from a set of points?
Here's one (temporary, grab it now)
http://www.oyonale.com/temp/splines.jpg
G.
--
**********************
http://www.oyonale.com
**********************
- Graphic experiments
- POV-Ray and Poser computer images
- Posters
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Thanks greatly. Was hermite really another name for one on the list?
Does the bezier always look cool with an "automatic" setting, is there code
for it anywhere out there?
"Gilles Tran" <gitran_nospam_@wanadoo.fr> wrote in message
news:4009da94$1@news.povray.org...
>
> news:web.4009c6d4976554543a5fb9ba0@news.povray.org...
> > Are there any pages out there that show actual comparison of the various
> > ways of making a curve from a set of points?
>
> Here's one (temporary, grab it now)
> http://www.oyonale.com/temp/splines.jpg
>
> G.
>
>
> --
> **********************
> http://www.oyonale.com
> **********************
> - Graphic experiments
> - POV-Ray and Poser computer images
> - Posters
>
>
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On Sat, 17 Jan 2004 18:35:48 EST, "gregjohn" <pte### [at] yahoo com> wrote:
> I just don't like the
> way the quadratic, cubic, and natural splines look with a set of points
You could be interested in akima- , tcb- or x-splines. I have patched POV-Ray
for such splines and googling you can find math behind them.
tcb_spline
http://news.povray.org/povray.binaries.images/31196/
akima_spline
http://news.povray.org/povray.binaries.images/31227/
basic_X_spline
http://news.povray.org/povray.binaries.images/31266/
extended_X_spline
http://news.povray.org/povray.binaries.images/31279/
http://news.povray.org/povray.binaries.animations/31278/
general_X_spline
http://news.povray.org/povray.binaries.images/31435/
http://news.povray.org/povray.binaries.animations/31434/
ABX
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Wild. I'm looking for a good approximation of octopus tenacle. I was
hoping I could just throw out a couple of random points in space and some
kind of spline would come along and make a line in the natural shape of an
(uninjured) octopus's tenacle.
"ABX" <abx### [at] abxartpl> wrote in message
news:jl4n001ogj0klas65mn2s2u14dcmbv4561@4ax.com...
>
> You could be interested in akima- , tcb- or x-splines. I have patched
POV-Ray
> for such splines and googling you can find math behind them.
>
> tcb_spline
> http://news.povray.org/povray.binaries.images/31196/
>
> akima_spline
> http://news.povray.org/povray.binaries.images/31227/
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On Mon, 19 Jan 2004 23:02:17 -0500, "Greg M. Johnson" <gregj;-)565### [at] aolcom>
wrote:
> Wild. I'm looking for a good approximation of octopus tenacle. I was
> hoping I could just throw out a couple of random points in space and some
> kind of spline would come along and make a line in the natural shape of an
> (uninjured) octopus's tenacle.
IMO akima spline seems best for such purpose, thought you would had to
calculate it yourself using macros until this is not released within next
MegaPOV :-( I'm affraid currently whole on-line information about akima
splines is available in form of Fortran, C, C++ sources :-(
ABX
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"Greg M. Johnson" <gregj;-)565### [at] aolcom> wrote:
> Wild. I'm looking for a good approximation of octopus tenacle. I was
> hoping I could just throw out a couple of random points in space and some
> kind of spline would come along and make a line in the natural shape of an
> (uninjured) octopus's tenacle.
The Spline Macro File supports TCB splines, their subsets cardinal and
Catmull-Rom splines, and bezier splines (see
http://www.geocities.com/ccolefax/spline/ for images showing how these
work).
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