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9 Aug 2022 15:33:36 EDT (-0400)
  Spiral (Message 17 to 26 of 26)  
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From: David Buck
Subject: Re: Spiral
Date: 6 Feb 2022 16:07:21
Message: <62003889$1@news.povray.org>
I'm happy that I've been able to play a part in this project.  It's been 
a fun ride and still a source of pride for me.

David

On 2022-02-06 12:54 p.m., Cousin Ricky wrote:
> P.S. I believe this is our first direct communication, so let me take
> this opportunity to thank you for DKBTrace and POV-Ray.


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From: Cousin Ricky
Subject: Re: Spiral
Date: 8 Feb 2022 16:40:50
Message: <6202e362$1@news.povray.org>
On 2022-02-03 11:19 (-4), Cousin Ricky wrote:
> 
> Still tuning the macro, but it's essentially done.  This image is made
> with spheres and cylinders, but it can easily be switched to a sphere_sweep.

Spheres and cones, actually.  My macro calls SphereSweep from the Object
Collection, and on the quoted post I wasn't thinking about how
SphereSweep did its job.

I was planning to wean my macro off SphereSweep, but then it occurred to
me that a sudden change in color might be too drastic a change in sphere
sizes to connect with a cone.  I'm talking degenerate cone and square
root of a negative number parse errors here.  SphereSweep handles these
complications automatically, so I'm just going to keep it as a prerequisite.


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spiral_cones-pbi.jpg


 

From: Kenneth
Subject: Re: Spiral
Date: 10 Feb 2022 13:35:00
Message: <web.620559d3c95e65754cef624e6e066e29@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
>
> Not the same, but this reminds me of Kenneth's airbrush technique
> (2008, iirc). I am unable to find the exact post here.
> ...
> I was thinking this:
>

Sorry for not posting here earlier; I was totally absorbed in running camera
'normal' experiments.

Hmm, I don't remember posting those images, although they look like the
experiments you and I did in my long-ago post (the one that Yadgar referenced).
Perhaps from a different 'Kenneth'? I searched all of the image posts for 2008
and didn't see another fellow by that name. TWO users named Kenneth??
Impossible! :-P

Anyway...I really like these spiral experiments. I was thinking about the
earlier suggestion of somehow using the technique to reproduce a full-color
photo-- perhaps by making separate spirals of the image's 3 separate color
channels (with the spirals colored red/green/blue), but having different
spacings or gaps between the spirals so that they sort of 'blend together' in
the viewer's eye. I haven't thought this through in detail, though. By using
different spiral 'frequencies? Maybe it's not possible geometrically.


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From: m@b
Subject: Re: Spiral
Date: 11 Feb 2022 02:20:29
Message: <62060e3d@news.povray.org>
On 06/02/2022 11:22 pm, David Buck wrote:
> This makes me wonder if you could get the illusion of a full-color image 
> by having three spirals - one red, one green and one blue - that are 
> separate but which spiral out together.
> 
> David

It's quick and dirty, but here it is, 3 spirals, one red, one green and 
one blue:


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Attachments:
Download 'spiral 04a.png' (143 KB) Download 'spiral 04b.png' (116 KB)

Preview of image 'spiral 04a.png'
spiral 04a.png

Preview of image 'spiral 04b.png'
spiral 04b.png


 

From: Thomas de Groot
Subject: Re: Spiral
Date: 11 Feb 2022 02:36:47
Message: <6206120f$1@news.povray.org>
Op 10/02/2022 om 19:31 schreef Kenneth:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>>
>> Not the same, but this reminds me of Kenneth's airbrush technique
>> (2008, iirc). I am unable to find the exact post here.
>> ...
>> I was thinking this:
>>
> 
> Sorry for not posting here earlier; I was totally absorbed in running camera
> 'normal' experiments.
> 
> Hmm, I don't remember posting those images, although they look like the
> experiments you and I did in my long-ago post (the one that Yadgar referenced).
> Perhaps from a different 'Kenneth'? I searched all of the image posts for 2008
> and didn't see another fellow by that name. TWO users named Kenneth??
> Impossible! :-P
> 
Sorry, a little misunderstanding here. The images were by me; the 
technique was yours ;-)

Probably what Yadgar mentioned. Must have been around July 2008...

> Anyway...I really like these spiral experiments. I was thinking about the
> earlier suggestion of somehow using the technique to reproduce a full-color
> photo-- perhaps by making separate spirals of the image's 3 separate color
> channels (with the spirals colored red/green/blue), but having different
> spacings or gaps between the spirals so that they sort of 'blend together' in
> the viewer's eye. I haven't thought this through in detail, though. By using
> different spiral 'frequencies? Maybe it's not possible geometrically.
> 

By using eval_pigment perhaps, or a pigment function, to evaluate the 
colour, then using the result to change the colour of the individual 
cones in the spiral...?

-- 
Thomas


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From: Thomas de Groot
Subject: Re: Spiral
Date: 11 Feb 2022 02:40:58
Message: <6206130a$1@news.povray.org>
Op 11/02/2022 om 08:20 schreef m@b:
> On 06/02/2022 11:22 pm, David Buck wrote:
>> This makes me wonder if you could get the illusion of a full-color 
>> image by having three spirals - one red, one green and one blue - that 
>> are separate but which spiral out together.
>>
>> David
> 
> It's quick and dirty, but here it is, 3 spirals, one red, one green and 
> one blue:

Yes! Excellent!

I wondered earlier, in my answer to Kenneth here, if it would be 
possible to tint differently individual cones in a spiral? That way only 
one spiral would be needed, but I guess that is not allowed.

-- 
Thomas


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From: Kenneth
Subject: Re: Spiral
Date: 11 Feb 2022 11:35:00
Message: <web.62068ffac95e65754cef624e6e066e29@news.povray.org>
"m@b" <sai### [at] googlemailcom> wrote:
> On 06/02/2022 11:22 pm, David Buck wrote:
> > This makes me wonder if you could get the illusion of a full-color image
> > by having three spirals - one red, one green and one blue - that are
> > separate but which spiral out together.
> >
> > David
>
> It's quick and dirty, but here it is, 3 spirals, one red, one green and
> one blue:

It worked! That is really cool.

I half-thought that the solution might be to simply scale each successive spiral
slightly larger. But instead, it looks like each spiral begins (in the center)
at 120-degree rotations from each other. Great! I imagine that *more* than 3
colors could be used with the same technique, by simply dividing-up the
rotations differently (and making the spirals appropriately thinner, maybe.)
Like, 6 spirals-colors would use 360/6 rotation adjustments.


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From: David Buck
Subject: Re: Spiral
Date: 11 Feb 2022 20:01:27
Message: <620706e7$1@news.povray.org>
Wow.  I think that works really well.  If you look closely, you just see 
red, green and blue but an overall glance gives you subtle shades of 
color.  Cool!

David Buck

On 2022-02-11 2:20 a.m., m@b wrote:
> On 06/02/2022 11:22 pm, David Buck wrote:
>> This makes me wonder if you could get the illusion of a full-color 
>> image by having three spirals - one red, one green and one blue - that 
>> are separate but which spiral out together.
>>
>> David
> 
> It's quick and dirty, but here it is, 3 spirals, one red, one green and 
> one blue:


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From: Bald Eagle
Subject: Re: Spiral
Date: 12 Feb 2022 10:40:00
Message: <web.6207d45fc95e65751f9dae3025979125@news.povray.org>
David Buck <dav### [at] simberoncom> wrote:
> Wow.  I think that works really well.  If you look closely, you just see
> red, green and blue but an overall glance gives you subtle shades of
> color.  Cool!


Right, I saw this effect a while ago, and hadn't gotten around to posting it.
Now it seems like it might have some utility to inspire some experimentation.
:)

https://petapixel.com/2019/07/31/this-black-and-white-photo-uses-color-grid-lines-to-trick-your-brain/

Pretty cool effect / illusion.

I wonder if all 3 spirals could be coincident or layered with rgbf pigments.

Also wondering what a single spiral of closely arranged spheres would look like
with full rgb pigmentation of each individual sphere...


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From: Cousin Ricky
Subject: Re: Spiral
Date: 12 Feb 2022 16:56:18
Message: <62082d02@news.povray.org>
On 2022-02-06 11:22 (-4), David Buck wrote:
> This makes me wonder if you could get the illusion of a full-color image
> by having three spirals - one red, one green and one blue - that are
> separate but which spiral out together.

Turns out it wasn't so difficult.

The file sizes for these things are tricky.  Quite often, the PNGs are
smaller than the JPEGs, though I can /sometimes/ get the JPEGs smaller
by using compression 75.


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me-pats-cspiral.png


 

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