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From: Tek
Subject: Re: Copying pigments with crackle (124k jpg)
Date: 30 Jul 2008 15:50:55
Message: <4890c61f$1@news.povray.org>
Actually I want dotted white lines on the road, i.e. I need a pattern that's 
a perpendicular gradient to crackle. I'm almost completely certain it's 
impossible!

For my city I got windows on the buildings using a slope_mapped pattern on 
the isosurface, with window patterns arranged for the 8 possible wall angles 
that occur on that metric 1 isosurface. But of course that slope_map 
wouldn't work on the flat road.

Though... that gives me an idea. maybe I can borrow your technique to sample 
the gradient, then use that to index a pattern according to the gradient... 
i.e. I could have a pattern for north-south lines, and map it onto east-west 
gradients. There'd be discontinuities round the edge, and it wouldn't work 
on the flat bits of metric 1, but it should be fine for my dotted white 
lines...

Still, this all sounds like a lot more trouble than it's worth!

-- 
Tek
http://evilsuperbrain.com

"Samuel Benge" <stb### [at] hotmailcom> wrote in message 
news:web.4890be074f928167ff8a991c0@news.povray.org...
> "Tek" <tek### [at] evilsuperbraincom> wrote:
>> "stbenge" <THI### [at] hotmailcom> wrote in message
>> > Yes, you can get some interesting effects. Here, try this out:
>>
>> Yeah but it distorts the pattern, one of the things that's great about 
>> your
>> first post is that it duplicates my pattern into every cell, but with 
>> metric
>> one it breaks it.
>
> Hmm, I don't know if what you want is possible... "You can't change the 
> laws of
> physics," as my mom would say, or in this case, the laws of mathematics ;)
>
>> > It makes rectangular masses all over the place. Nest a few of those 
>> > with
>> > different translation values, and a cityscape might be possible.
>>
>> I've already got the city:
>>
> Ah yes, now I remember.
>
>> But I really need a perpendicular pattern to the crackle, something like 
>> the
>> radial example in your original post, but perpendicular to metric 1.
>> I don't think it's possible though :(
>
> What are you after? Are you planning to make vertical ridges going up 
> along the
> sides of each building? Can my code (without metric 1) be applied into 
> each
> metric 1 cell to achieve your goal? It wouldn't wrap perfectly around the
> metric 1 cells, but would still be central to each cell. Buried in a
> pigment_map, you could hide the discontinuities between the metric 1 and 
> metric
> 2 cell edges.
>
> Sam
>


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From: stbenge
Subject: Re: Copying pigments with crackle (124k jpg)
Date: 30 Jul 2008 17:15:47
Message: <4890da03@news.povray.org>
Tek wrote:
> Actually I want dotted white lines on the road, i.e. I need a pattern that's 
> a perpendicular gradient to crackle. I'm almost completely certain it's 
> impossible!

Even if you could get that to work (nothing is impossible, only 
improbable...), wouldn't some of the dotted lines be wedge-shaped?

> Still, this all sounds like a lot more trouble than it's worth!

It probably is. Sometimes it's better to just sit down and make macros 
to be called randomly.

If you really have your heart set on making the buildings conform to a 
crackle-like geometry, perhaps you should try your hand at learning how 
voronoi diagrams work. You would have more control over all your objects 
and textures that way.

I've been thinking about learning how voronoi geometry works. I'm sure 
that knowledge will lead to something interesting!

Sam


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From: Bryan Valencia
Subject: Re: Copying pigments with crackle (124k jpg)
Date: 31 Jul 2008 03:09:08
Message: <48916514$1@news.povray.org>
Tek wrote:
> Crackle seems to be pov's slowest pattern, and this technique accesses it 
> multiple times.
> 
So, are you saying that for faster renders, don't be a crackle ho?


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From: Tom York
Subject: Re: Copying pigments with crackle (124k jpg)
Date: 31 Jul 2008 14:40:00
Message: <web.489206dd4f9281677d55e4a40@news.povray.org>
"Tek" <tek### [at] evilsuperbraincom> wrote:
> Actually I want dotted white lines on the road, i.e. I need a pattern that's
> a perpendicular gradient to crackle. I'm almost completely certain it's
> impossible!

A sort of pattern version of the Delaunay triangulation?

Tom


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