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From: Bald Eagle
Subject: Re: Stacking stones without overlapping
Date: 19 Jun 2017 13:45:05
Message: <web.59480cabd8d105e9c437ac910@news.povray.org>
There's also the related isosurface method:

http://www.econym.demon.co.uk/isotut/printable.htm#CH_pigment

http://www.econym.demon.co.uk/isotut/pigment.jpg


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From: Ari
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 15:10:00
Message: <web.59497214d8d105e99d2528170@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> dick balaska <dic### [at] buckosoftcom> wrote:
>
>
> > I, too, use a Java program to position grains. I found SDL to be
> > hideously slow when doing a 1600 x 1600 loop. ;)
> > http://www.buckosoft.com/tteoac/video/frames/ttfo0177.png
>
> It's always helpful when expediency is the goal -  to recognize the practical
> solutions and take the path of least resistance.
>
> > I love Sam's idea; pick a position and then alter the blob's shape and
> > size to fit the position.
>
> Yes, that's an interesting idea - well worth looking into to see how difficult
> that would be to do well.
>
> I was thinking something along the lines of this:
>
>
https://www.researchgate.net/figure/273284325_fig7_Figure-7-An-example-of-a-Voronoi-diagram-in-Laguerre-geometry-for-
a-
> set-of-multi-sized
>
> Where the spaces and centers are well defined, and then the sphere radii could
> be easily computed.  That would get one far along the path.  Although I think
> that the appropriate crackle metric and offset settings would get it all done
> lickety-split.

Hi, everyone.
I have been spending time searching on the internet and reading your guys'
information. However, I realized almost all of them required "some mathematical
background", especially Voronoi Diagram being shown the most frequently. I try
my best to understand them but I can't due to the lack of Maths background(I
only know some integration/sequence and differentiation from classes :( ). I
then try to work with an external program but I don't how to make use of it
well. (I installed the pyvoro in Python) So, I just went back to the basic now.
( Damn, I am stupid! Just want to cry in a corner) So far I just wrote this one:

#declare Grain = array[10000]   ;
#declare Nr = 0    ;
#declare Position = seed(100)  ;
#declare Size = seed(123)   ;
#while (Nr < 10000)
    sphere{<rand(Position), rand(Position), rand(Position)>, rand(Size)*.1
            pigment {color rgb<rand(Size), rand(Size), rand(Size)>} }
    #declare Grain[Nr] = sphere{<rand(Position), rand(Position),
rand(Position)>, rand(Size)*.1
            pigment {color rgb<rand(Size), rand(Size), rand(Size)>} }
    #declare Nr = Nr + 1;
#end

I think I will then try to develop it a little bit further according to the
'distance test formula' from the 'Pebbles' example. My idea now is to test every
Grain[Nr] vs Grain[Nr-1] Grain[Nr-2]......Grain[0] if their distance between two
centers is smaller than their sum of radii. It's 3 a.m. now here guys. I think I
might just sleep and work it out tomorrow. Thank you guys for helping me at
first but I think I have to say I am too stupid to understand them :'(.


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From: Ari
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 15:10:01
Message: <web.5949729fd8d105e99d2528170@news.povray.org>
Hi, everyone.
I have been spending time searching on the internet and reading your guys'
information. However, I realized almost all of them required "some mathematical
background", especially Voronoi Diagram being shown the most frequently. I try
my best to understand them but I can't due to the lack of Maths background(I
only know some integration/sequence and differentiation from classes :( ). I
then try to work with an external program but I don't how to make use of it
well. (I installed the pyvoro in Python) So, I just went back to the basic now.
( Damn, I am stupid! Just want to cry in a corner) So far I just wrote this one:

#declare Grain = array[10000]   ;
#declare Nr = 0    ;
#declare Position = seed(100)  ;
#declare Size = seed(123)   ;
#while (Nr < 10000)
    sphere{<rand(Position), rand(Position), rand(Position)>, rand(Size)*.1
            pigment {color rgb<rand(Size), rand(Size), rand(Size)>} }
    #declare Grain[Nr] = sphere{<rand(Position), rand(Position),
rand(Position)>, rand(Size)*.1
            pigment {color rgb<rand(Size), rand(Size), rand(Size)>} }
    #declare Nr = Nr + 1;
#end

I think I will then try to develop it a little bit further according to the
'distance test formula' from the 'Pebbles' example. My idea now is to test every
Grain[Nr] vs Grain[Nr-1] Grain[Nr-2]......Grain[0] if their distance between two
centers is smaller than their sum of radii. It's 3 a.m. now here guys. I think I
might just sleep and work it out tomorrow. Thank you guys for helping me at
first but I think I have to say I am too stupid to understand them :'(.


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From: Stephen
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 15:57:43
Message: <59497e37@news.povray.org>
On 6/20/2017 8:08 PM, Ari wrote:
>   I try
> my best to understand them but I can't due to the lack of Maths background(I
> only know some integration/sequence and differentiation from classes:(  ).

You and me both. :)

-- 

Regards
     Stephen


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From: Bald Eagle
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 16:55:00
Message: <web.59498b72d8d105e9c437ac910@news.povray.org>
"Ari" <win### [at] yahoocomhk> wrote:
> Hi, everyone.
> I have been spending time searching on the internet and reading your guys'
> information. However, I realized almost all of them required "some mathematical
> background", especially Voronoi Diagram being shown the most frequently. I try
> my best to understand them but I can't due to the lack of Maths background(I
> only know some integration/sequence and differentiation from classes :( ). I
> then try to work with an external program but I don't how to make use of it
> well. (I installed the pyvoro in Python) So, I just went back to the basic now.
> ( Damn, I am stupid! Just want to cry in a corner)

I think you'll be fine.
A lot of stuff was thrown at you all at once.
Voronoi / Delaunay is NOT an easy thing to do from scratch - which is why Sam
Benge used an external program to generate his data set.
Pov-ray's crackle pattern is essentially a Voronoi diagram, and you can use it
to make a pattern, or pass it to an isosurface as a function, to get "real 3d"
shapes.
I'd start with the spheres like you're doing, and then you can get a working
scene, and practice with POV-Ray's SDL syntax, and programming logic.


No worries - it'll be ok   ;)


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From: Stephen
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 17:04:39
Message: <59498de7$1@news.povray.org>
On 6/20/2017 8:57 PM, Stephen wrote:
> On 6/20/2017 8:08 PM, Ari wrote:
>>   I try
>> my best to understand them but I can't due to the lack of Maths
>> background(I
>> only know some integration/sequence and differentiation from
>> classes:(  ).
>
> You and me both. :)
>

So what I would do, knowing that most of the guys here have been using 
PovRay for years and they are wizards at maths and programming. Is to 
start simple then refine it as you go along.
The image you linked to was by someone who stuns everyone with his work. 
So it is not a fair goal to try and do in a couple of months.

If you look at the trace function it will tell you how far away an 
object is from a reference point. If you move that reference point in a 
regular scan. You can build up a pattern of spheres. When you are happy 
with that you can then add some randomness to what you are building. 
Irregular scaling of the spheres to be laid down to give the impression 
of stones. offset the trace reference point so the spheres don't stack 
up in columns etc.
Then you will get ideas of your own to enhance it.

Remember us enjuneers have to make thinks work. And if it doesn't fit 
use a bigger hammer. ;-)

-- 

Regards
     Stephen


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From: Stephen
Subject: Re: Stacking stones without overlapping
Date: 20 Jun 2017 17:18:42
Message: <59499132$1@news.povray.org>
On 6/20/2017 9:54 PM, Bald Eagle wrote:
> "Ari" <win### [at] yahoocomhk> wrote:
>> Hi, everyone.
>> I have been spending time searching on the internet and reading your guys'
>> information. However, I realized almost all of them required "some mathematical
>> background", especially Voronoi Diagram being shown the most frequently. I try
>> my best to understand them but I can't due to the lack of Maths background(I
>> only know some integration/sequence and differentiation from classes :( ). I
>> then try to work with an external program but I don't how to make use of it
>> well. (I installed the pyvoro in Python) So, I just went back to the basic now.
>> ( Damn, I am stupid! Just want to cry in a corner)
>
> I think you'll be fine.
> A lot of stuff was thrown at you all at once.
> Voronoi / Delaunay is NOT an easy thing to do from scratch - which is why Sam
> Benge used an external program to generate his data set.
> Pov-ray's crackle pattern is essentially a Voronoi diagram, and you can use it
> to make a pattern, or pass it to an isosurface as a function, to get "real 3d"
> shapes.
> I'd start with the spheres like you're doing, and then you can get a working
> scene, and practice with POV-Ray's SDL syntax, and programming logic.
>
>

You know the differences in our outlooks on this problem are quite 
philosophical. But this is not the time to go into it. There is no good 
reason to. It would only be confusing.

> No worries - it'll be ok   ;)
>

Yes it will be. :)



-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Stacking stones without overlapping
Date: 21 Jun 2017 02:45:54
Message: <594a1622@news.povray.org>
On 20-6-2017 23:04, Stephen wrote:
> On 6/20/2017 8:57 PM, Stephen wrote:
>> On 6/20/2017 8:08 PM, Ari wrote:
>>>   I try
>>> my best to understand them but I can't due to the lack of Maths
>>> background(I
>>> only know some integration/sequence and differentiation from
>>> classes:(  ).
>>
>> You and me both. :)
>>
> 
> So what I would do, knowing that most of the guys here have been using 
> PovRay for years and they are wizards at maths and programming. Is to 
> start simple then refine it as you go along.
> The image you linked to was by someone who stuns everyone with his work. 
> So it is not a fair goal to try and do in a couple of months.
> 
> If you look at the trace function it will tell you how far away an 
> object is from a reference point. If you move that reference point in a 
> regular scan. You can build up a pattern of spheres. When you are happy 
> with that you can then add some randomness to what you are building. 
> Irregular scaling of the spheres to be laid down to give the impression 
> of stones. offset the trace reference point so the spheres don't stack 
> up in columns etc.
> Then you will get ideas of your own to enhance it.

That is a good way to start. I shall have to try that scenario myself 
too I guess: been years since I wanted to explore that path. :-)

> 
> Remember us enjuneers have to make thinks work. And if it doesn't fit 
> use a bigger hammer. ;-)
> 

Not only enjuneers. Small apes like me too (using stones)... ;-)

-- 
Thomas


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From: Stephen
Subject: Re: Stacking stones without overlapping
Date: 21 Jun 2017 05:40:49
Message: <594a3f21$1@news.povray.org>
On 6/21/2017 7:45 AM, Thomas de Groot wrote:
> On 20-6-2017 23:04, Stephen wrote:

>> So what I would do, knowing that most of the guys here have been using
>> PovRay for years and they are wizards at maths and programming. Is to
>> start simple then refine it as you go along.
>> The image you linked to was by someone who stuns everyone with his
>> work. So it is not a fair goal to try and do in a couple of months.
>>
>> If you look at the trace function it will tell you how far away an
>> object is from a reference point. If you move that reference point in
>> a regular scan. You can build up a pattern of spheres. When you are
>> happy with that you can then add some randomness to what you are
>> building. Irregular scaling of the spheres to be laid down to give the
>> impression of stones. offset the trace reference point so the spheres
>> don't stack up in columns etc.
>> Then you will get ideas of your own to enhance it.
>
> That is a good way to start. I shall have to try that scenario myself
> too I guess: been years since I wanted to explore that path. :-)
>

If I can find the time I will try it in Blender. But the learning. :)
>>
>> Remember us enjuneers have to make thinks work. And if it doesn't fit
>> use a bigger hammer. ;-)
>>
>
> Not only enjuneers. Small apes like me too (using stones)... ;-)
>

[Top tip] Tie a stick to your stone. :)
-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: Stacking stones without overlapping
Date: 21 Jun 2017 07:13:22
Message: <594a54d2$1@news.povray.org>
On 21-6-2017 11:40, Stephen wrote:
> On 6/21/2017 7:45 AM, Thomas de Groot wrote:
>> On 20-6-2017 23:04, Stephen wrote:
> 
>>> So what I would do, knowing that most of the guys here have been using
>>> PovRay for years and they are wizards at maths and programming. Is to
>>> start simple then refine it as you go along.
>>> The image you linked to was by someone who stuns everyone with his
>>> work. So it is not a fair goal to try and do in a couple of months.
>>>
>>> If you look at the trace function it will tell you how far away an
>>> object is from a reference point. If you move that reference point in
>>> a regular scan. You can build up a pattern of spheres. When you are
>>> happy with that you can then add some randomness to what you are
>>> building. Irregular scaling of the spheres to be laid down to give the
>>> impression of stones. offset the trace reference point so the spheres
>>> don't stack up in columns etc.
>>> Then you will get ideas of your own to enhance it.
>>
>> That is a good way to start. I shall have to try that scenario myself
>> too I guess: been years since I wanted to explore that path. :-)
>>
> 
> If I can find the time I will try it in Blender. But the learning. :)
>>>
>>> Remember us enjuneers have to make thinks work. And if it doesn't fit
>>> use a bigger hammer. ;-)
>>>
>>
>> Not only enjuneers. Small apes like me too (using stones)... ;-)
>>
> 
> [Top tip] Tie a stick to your stone. :)

Tried that. Stick broke. :={

-- 
Thomas


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