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From: Christopher James Huff
Subject: Voronoi pattern - attached files (1/1)
Date: 25 Dec 2003 19:58:20
Message: <cjameshuff-CC249E.19575925122003@netplex.aussie.org>
Here's a little patch I've been working on. It is very similar to the 
crackle pattern, but rather than using a 3D grid of points that is 
randomly jittered, it uses a user-specified set of points. It is 
actually very fast, usually faster than the crackle pattern. It stores 
the points in a binary space partition tree, which it can then search 
very quickly, while the crackle pattern must always check a large number 
of points, and sometimes recompute all of them. The options available 
are the same as for the crackle pattern, with the addition of the 
points. You can specify the points alone, or with a blend map index for 
each point, giving you an effect similar to the "solid" feature, but 
with much more control.



-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/


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Attachments:
Download 'voronoi1.jpg' (32 KB) Download 'voronoi2.jpg' (12 KB) Download 'voronoi3.jpg' (13 KB)

Preview of image 'voronoi1.jpg'
voronoi1.jpg

Preview of image 'voronoi2.jpg'
voronoi2.jpg

Preview of image 'voronoi3.jpg'
voronoi3.jpg


 

From: George Pantazopoulos
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 25 Dec 2003 21:49:20
Message: <opr0roznhnhr234r@news.povray.org>
Nice one, Chris! Source! Source! :)

How is a Voronoi Diagram/Delunay triangulation generated from a BSP tree?

George


On Thu, 25 Dec 2003 19:57:59 -0500, Christopher James Huff 
<cja### [at] earthlinknet> wrote:

> Here's a little patch I've been working on. It is very similar to the
> crackle pattern, but rather than using a 3D grid of points that is
> randomly jittered, it uses a user-specified set of points. It is
> actually very fast, usually faster than the crackle pattern. It stores
> the points in a binary space partition tree, which it can then search
> very quickly, while the crackle pattern must always check a large number
> of points, and sometimes recompute all of them. The options available
> are the same as for the crackle pattern, with the addition of the
> points. You can specify the points alone, or with a blend map index for
> each point, giving you an effect similar to the "solid" feature, but
> with much more control.
>
>
>



-- 
Using M2, Opera's revolutionary e-mail client: http://www.opera.com/m2/


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From: Dennis Miller
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 25 Dec 2003 22:00:54
Message: <3feba466$1@news.povray.org>
Seems like this is something that is not yet supported in the official 3.5,
correct?
Very nice work.
Dennis


"Christopher James Huff" <cja### [at] earthlinknet> wrote in message
news:cja### [at] netplexaussieorg...
> Here's a little patch I've been working on. It is very similar to the
> crackle pattern, but rather than using a 3D grid of points that is
> randomly jittered, it uses a user-specified set of points. It is
> actually very fast, usually faster than the crackle pattern. It stores
> the points in a binary space partition tree, which it can then search
> very quickly, while the crackle pattern must always check a large number
> of points, and sometimes recompute all of them. The options available
> are the same as for the crackle pattern, with the addition of the
> points. You can specify the points alone, or with a blend map index for
> each point, giving you an effect similar to the "solid" feature, but
> with much more control.
>
>
>
> -- 
> Christopher James Huff <cja### [at] earthlinknet>
> http://home.earthlink.net/~cjameshuff/
> POV-Ray TAG: <chr### [at] tagpovrayorg>
> http://tag.povray.org/
>
>


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From: Christopher James Huff
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 25 Dec 2003 22:01:12
Message: <cjameshuff-B61EB6.22011625122003@netplex.aussie.org>
In article <opr0roznhnhr234r@news.povray.org>,
 George Pantazopoulos <george@gamma*KILLSPAM*burst.net> wrote:

> How is a Voronoi Diagram/Delunay triangulation generated from a BSP tree?

The same way the crackle pattern does it. The distances of the three 
nearest points are found, and the pattern value is computed from that. 
The voronoi pattern just stores user-defined points in a quickly 
searchable tree structure, rather than generating pseudo-random points 
(stored in a cache array) on the fly.


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From: Christopher James Huff
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 25 Dec 2003 22:14:25
Message: <cjameshuff-EF7CCA.22142925122003@netplex.aussie.org>
In article <3feba466$1@news.povray.org>,
 "Dennis Miller" <dhm### [at] comcastnet> wrote:

> Seems like this is something that is not yet supported in the official 3.5,
> correct?

Correct, this is a patch I created.


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From: Jim Charter
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 26 Dec 2003 00:33:34
Message: <3febc82e@news.povray.org>
Looks very exciting.  What are the options for specifyimg points?  Could 
the vertices of a mesh be used for instance?


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From: Slime
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 26 Dec 2003 02:39:39
Message: <3febe5bb$1@news.povray.org>
> rather than using a 3D grid of points that is
> randomly jittered, it uses a user-specified set of points.

Can they be 4D? =)

 - Slime
 [ http://www.slimeland.com/ ]


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From: Christopher James Huff
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 26 Dec 2003 11:18:24
Message: <cjameshuff-FA2691.11182926122003@netplex.aussie.org>
In article <3febe5bb$1@news.povray.org>, "Slime" <fak### [at] emailaddress> 
wrote:

> > rather than using a 3D grid of points that is
> > randomly jittered, it uses a user-specified set of points.
> 
> Can they be 4D? =)

It would actually be pretty easy to do, and it's a feature I've been 
looking at implementing. In a way, they are already...the offset feature 
specifies the distance along the fourth dimension of all the points. You 
just can't have variation in that direction.
Anyway, I do plan on trying it out, as part of some extensions to the 
BSP code to more optimally handle the 2D and 1D cases (where all points 
are in a axis-aligned plane or aligned along a line).

I'd also like to implement a 4D noise pattern, which is something I've 
seen used for things like flames...


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From: Christopher James Huff
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 26 Dec 2003 11:25:01
Message: <cjameshuff-A38EB9.11250626122003@netplex.aussie.org>
In article <3febc82e@news.povray.org>, Jim Charter <jrc### [at] msncom> 
wrote:

> Looks very exciting.  What are the options for specifyimg points?  Could 
> the vertices of a mesh be used for instance?

You either specify point vectors or float-vector pairs. If the latter, 
the result is similar to crackle with the solid feature turned on, 
except that it uses the specified value for that cell rather than a 
pseudo-random one. The points can be whatever you want...mesh vertices 
would work, but you would have to extract the actual vertex locations.

voronoi {
    offset FLOAT
    form FLOAT
    metric FLOAT (actually a vector, but only the x component is used)

    POINTS
}

POINTS:
    VECTOR,
    VECTOR,
    VECTOR...
or:
    [FLOAT VECTOR]
    [FLOAT VECTOR]
    [FLOAT VECTOR]

You must specify at least 3 points, but that is the only restriction.


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From: ingo
Subject: Re: Voronoi pattern - attached files (1/1)
Date: 26 Dec 2003 12:22:59
Message: <Xns945DBB0061824seed7@netplex.aussie.org>
in news:cja### [at] netplexaussieorg Christopher 
James Huff wrote:

> Here's a little patch I've been working on. It is very similar to the 
> crackle pattern, but rather than using a 3D grid of points that is 
> randomly jittered, it uses a user-specified set of points.

Looks very interesting.

Is the pattern infinite?

A thought, triggerd by your pattern: In the crackle pattern, would it be 
possible to make the position of the centeroids controlable by some 
function? 
I'm thinking of something like, put all the centeroids in the centre and 
than give them a random deviation from there with a certain (Gauss) 
distribution. 
Or, make the position of the centeroid in the box depend on another 
pattern. Imagine a wood pattern, in the light parts of it the centeroids 
are "more random" where as in the dark parts they are very close to the 
centre of the box. That would give bands of more and less uniform 
crackles.
Or, with the same wood pattern, in the lighter area's the centeroids are 
closer to the sides of the box and in the darker area they ar closer to 
the center.


Ingo


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