 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I'm trying to make another step forward with my
Mesh-Modifying-Macros. What I'm trying to find
is a method to convert the 2D-Grid of heights
(similiar to a heightfield's pixels) into a set of
POV-native bezier-patches. I'd like to use some
non-patented, efficient algorithm for this, but could
also come up with my own method. The difficult
thing is that I need a system which will convert
4 corners to one patch.
I've already come up with a method which will
get me the outer 12 control points for the patch,
which'll line up with the next patch, cause they'll
all be based upon the same data. But how about
the 4 center nodes? Unless I want to script several
#if statements to catch if I'm accessing indices too
high or too low for the data, this might become a
pretty slow algorithm. I'd rather like something faster.
Any ideas?
--
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmx de
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:3e8d9c42$1@news.povray.org Tim Nikias v2.0 wrote:
> The difficult thing is that I need a system which will convert
> 4 corners to one patch.
>
Don't know what exactly you want to achieve but how about generating a
grid of curves that goes through all given control points (heights).
http://users.pandora.be/desi-iii/SecretsE.html
Third section of the page (this would also be a nice spline/curve type
for a future POV-Ray version).
From this grid it should be possible to construct a Gordon Surface:
http://www.math.hmc.edu/
~gu/math142/mellon/Application_to_CAGD/Surface_Construction_Schem.html#g
ordon
http://olli.informatik.uni-
oldenburg.de/Grafiti3/grafiti/flow11/page3.html
http://www.cg.tuwien.ac.at/studentwork/CESCG99/MKuklisova/clanok.html
http://www.cg.tuwien.ac.at/studentwork/CESCG99/MKuklisova/node1.html
Due to lack of mathematical skills I've not been able to come up with a
macro that can generate these surfaces :(
Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 4 Apr 2003 11:47:04 -0500, ingo <ing### [at] tagpovrayorg> wrote:
> (this would also be a nice spline/curve type for a future POV-Ray version)
You mean akima_spline with requirement of 5 control points? Found it. Any other
spline type expectation ? References on www ?
ABX
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Fri, 4 Apr 2003 16:49:17 +0200, "Tim Nikias v2.0"
<tim### [at] gmxde> wrote:
>I'm trying to make another step forward with my
>Mesh-Modifying-Macros. What I'm trying to find
>is a method to convert the 2D-Grid of heights
>(similiar to a heightfield's pixels) into a set of
>POV-native bezier-patches.
Didn't someone post something similar just recently? It was called
BigPatch IIRC.
Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG e-mail : pet### [at] tagpovrayorg
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:asm29vgr8n2eu5ru39hkeiuul1hcqvf62q@4ax.com ABX wrote:
> You mean akima_spline with requirement of 5 control points? Found it.
Don't know about the 5 points. It is said that the Akima spline looks more
"natural" or "hand drawn" than other splines.
> Any other spline type expectation ? References on www ?
X-spline:
http://dept-info.labri.u-bordeaux.fr/~schlick/DOC/sig1.html
http://www.imm.dtu.dk/~jab/software.html#xsplines
Tension, Continuity & Bias (TCB) or Kochanek-Bartels spline
http://www.cubic.org/~submissive/sourcerer/hermite.htm#ma5.3
Ingo
Post a reply to this message
|
|
| |
| |
|
|
From: Tim Nikias v2 0
Subject: Re: Convert Heightfield-like data to Nurbs?
Date: 8 Apr 2003 09:19:18
Message: <3e92cc56@news.povray.org>
|
|
|
| |
| |
|
|
Thanks for all those links. I'll need some time flicking through
those, especially if I want to understand them... :-)
--
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde
>
> > The difficult thing is that I need a system which will convert
> > 4 corners to one patch.
> >
>
> Don't know what exactly you want to achieve but how about generating a
> grid of curves that goes through all given control points (heights).
>
> http://users.pandora.be/desi-iii/SecretsE.html
>
> Third section of the page (this would also be a nice spline/curve type
> for a future POV-Ray version).
>
>
> From this grid it should be possible to construct a Gordon Surface:
>
> http://www.math.hmc.edu/
> ~gu/math142/mellon/Application_to_CAGD/Surface_Construction_Schem.html#g
> ordon
>
> http://olli.informatik.uni-
> oldenburg.de/Grafiti3/grafiti/flow11/page3.html
>
> http://www.cg.tuwien.ac.at/studentwork/CESCG99/MKuklisova/clanok.html
> http://www.cg.tuwien.ac.at/studentwork/CESCG99/MKuklisova/node1.html
>
> Due to lack of mathematical skills I've not been able to come up with a
> macro that can generate these surfaces :(
>
> Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I'm the kind of guy who wants to script his
own stuff, because I like to learn more and
more as I move along.
--
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde
>
> >I'm trying to make another step forward with my
> >Mesh-Modifying-Macros. What I'm trying to find
> >is a method to convert the 2D-Grid of heights
> >(similiar to a heightfield's pixels) into a set of
> >POV-native bezier-patches.
>
> Didn't someone post something similar just recently? It was called
> BigPatch IIRC.
>
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] vipbg
> TAG e-mail : pet### [at] tagpovrayorg
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 7 Apr 2003 12:48:16 -0400, ingo <ing### [at] tagpovrayorg> wrote:
> Tension, Continuity & Bias (TCB) or Kochanek-Bartels spline
> http://www.cubic.org/~submissive/sourcerer/hermite.htm#ma5.3
Done with detailed control over incoming and outgoing tangent vectors.
http://news.povray.org/ltad9voejvpq5fc1j1i0h5fq73t0l3a48t%404ax.com
ABX
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 7 Apr 2003 12:48:16 -0400, ingo <ing### [at] tagpovrayorg> wrote:
> > You mean akima_spline with requirement of 5 control points? Found it.
>
> Don't know about the 5 points. It is said that the Akima spline looks more
> "natural" or "hand drawn" than other splines.
Do you have any application with Akima spline available ? Can you try following
set:
0,<0,0>
1,<0,2>
2,<2,1>
3,<0,0>
4,<-1,2>
5,<-2,1>
6,<-1,-1>
7,<0,0>
For me it looks like
http://news.povray.org/4qmk9v8lqb1nf22p3nfgcbcpco85g53rib%404ax.com
but I hardly see the most left part of this spline smooth.
ABX
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
in news:8umk9vghh0lg5p11tkanefo80rtldimhpl@4ax.com ABX wrote:
> Do you have any application with Akima spline available ?
I have none, sorry.
> For me it looks like
> http://news.povray.org/4qmk9v8lqb1nf22p3nfgcbcpco85g53rib%404ax.com
> but I hardly see the most left part of this spline smooth.
>
If you start drawing the spline somewhere else, is it still the last but
one point that gets a sharp bend, or is it always point <-1,-1>?
Ingo
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
