"LanuHum" <Lan### [at] yandexru> wrote:
> Hi! I am interested in the question: is it possible to create a thread without a
> mesh of triangles? We need a smooth surface of the thread in the picture
> 38400x21600 (4K * 10)

https://news.povray.org/5eec257c%241%40news.povray.org

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Le 2026-03-07 à 11:17, jr a écrit :
> hi,
> 
> "LanuHum" <Lan### [at] yandexru> wrote:
>> Wow. I found a rectangular thread in the documentation
> 
> nice.  as I said, I've no maths, but if that profile can be rotated by 45
> degrees..
> 
> 
> regards, jr.
> 
function{
      f_helix1(
         x,y,z,
         1,    // number of helixes, (1 = single helix, 2 = double helix 
etc.)
         22,   // period,      turns on the length of 2*pi
         0.07, // minor radius,
         0.80, // major radius,
         1,    // shape parameter,
         0.3,  // cross section type, (0.0 to 1.0 = square ... rounded 
to circle
               //     over 2.0 to 3.0 = rounded to diamond and concave 
diamond
         0     // cross section rotation angle
       )
   }

The last parameter «cross section rotation angle» is the rotation of the 
shape in degree.

The 9th parameter let you change the shape.

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"LanuHum" <Lan### [at] yandexru> wrote:
> Hi! I am interested in the question: is it possible to create a thread without a
> mesh of triangles? We need a smooth surface of the thread in the picture
> 38400x21600 (4K * 10)


Here is a simple idea.
#declare i=0;
#while(i<18 )
cone{0,.5,y*-.5,0 translate < .4,-2>  rotate y*360*i translate -y*i*.5
pigment{blue 1}}
 cone{0,.5,y*.5,0 translate <.4,-2>  rotate y*360*i translate -y*i*.5
pigment{red 1}}
#declare step=.01 ;
#declare i=i+step;
#end   translate <0,9,0>}

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Alain Martel <kua### [at] videotronca> wrote:

> function{
>       f_helix1(
>          x,y,z,
>          1,    // number of helixes, (1 = single helix, 2 = double helix
> etc.)
>          22,   // period,      turns on the length of 2*pi
>          0.07, // minor radius,
>          0.80, // major radius,
>          1,    // shape parameter,
>          0.3,  // cross section type, (0.0 to 1.0 = square ... rounded
> to circle
>                //     over 2.0 to 3.0 = rounded to diamond and concave
> diamond
>          0     // cross section rotation angle
>        )
>    }
>

> shape in degree.
>
> The 9th parameter let you change the shape.

The 9th parameter. I'm distracted.  I turned 90 degrees and saw no change. ))) I
should have been 45!!! Thank you so much!!!

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"Jeff Reifel" <jef### [at] gmailcom> wrote:
> "LanuHum" <Lan### [at] yandexru> wrote:
> > Hi! I am interested in the question: is it possible to create a thread without a
> > mesh of triangles? We need a smooth surface of the thread in the picture
> > 38400x21600 (4K * 10)
>
>
> Here is a simple idea.
> #declare i=0;
> #while(i<18 )
> cone{0,.5,y*-.5,0 translate < .4,-2>  rotate y*360*i translate -y*i*.5
> pigment{blue 1}}
>  cone{0,.5,y*.5,0 translate <.4,-2>  rotate y*360*i translate -y*i*.5
> pigment{red 1}}
> #declare step=.01 ;
> #declare i=i+step;
> #end   translate <0,9,0>}

Thanks, it's a good idea, but for a big picture you need to increase the number
of steps many times. Otherwise, defects are visible :(

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> "LanuHum" <Lan### [at] yandexru> wrote:
> > Hi! I am interested in the question: is it possible to create a thread
> > without a mesh of triangles?

"Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> https://news.povray.org/5eec257c%241%40news.povray.org

There is also this thread:
http://news.povray.org/povray.general/thread/%3Cweb.64ff068eb373d57cf00fef66b571e5b2%40news.povray.org%3E/

Always do a search for "prior art" when trying to accomplish a task.
"povray screw threads" or similar.

I'm sure there are several similar projects in the newsgroups - I know that I
have modeled screw threads and drill bits, and other helical shapes in the past.

- BE

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"LanuHum" <Lan### [at] yandexru> wrote:
> Hi! I am interested in the question: is it possible to create a thread without a
> mesh of triangles? We need a smooth surface of the thread in the picture
> 38400x21600 (4K * 10)

Hi, Also, though it may be less physically accurate with respect to its
geometry,
this scene on Jaime Vives Piqueres site still works out of the box and features
a nice lighting and composition setup:
http://ignorancia.org/uploads/zips/boltstill.zip
....If you just drop all of the lightsys macro files within the same folder :
http://ignorancia.org/uploads/zips/lightsys4b.zip

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"Bald Eagle" <cre### [at] netscapenet> wrote:
> > "LanuHum" <Lan### [at] yandexru> wrote:
> > > Hi! I am interested in the question: is it possible to create a thread
> > > without a mesh of triangles?
>
> "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> > https://news.povray.org/5eec257c%241%40news.povray.org
>
> There is also this thread:
>
http://news.povray.org/povray.general/thread/%3Cweb.64ff068eb373d57cf00fef66b571e5b2%40news.povray.org%3E/
>
> Always do a search for "prior art" when trying to accomplish a task.
> "povray screw threads" or similar.
>
> I'm sure there are several similar projects in the newsgroups - I know that I
> have modeled screw threads and drill bits, and other helical shapes in the past.
>
> - BE

Thanks. I tried to search, but immediately the word spiral thread is associated
with the hyper threads of a computer processor. )))

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"Mr" <m******r******at_hotmail_dot_fr> wrote:
> "LanuHum" <Lan### [at] yandexru> wrote:
> > Hi! I am interested in the question: is it possible to create a thread without a
> > mesh of triangles? We need a smooth surface of the thread in the picture
> > 38400x21600 (4K * 10)
>
> Hi, Also, though it may be less physically accurate with respect to its
> geometry,
> this scene on Jaime Vives Piqueres site still works out of the box and features
> a nice lighting and composition setup:
> http://ignorancia.org/uploads/zips/boltstill.zip
> ....If you just drop all of the lightsys macro files within the same folder :
> http://ignorancia.org/uploads/zips/lightsys4b.zip

Hi! Thanks, I saw a height_field in the file. This is a bad decision for my
purpose. Scattering media with photons example + drum kit. 2 Up pictures from
documentation and demo scenes. I want to create a real scene based on two
examples from the documentation. The camera will be in different locations. In
some cases, this spiral thread will be perfectly visible.I need clear, smooth
lines with no signs of a low-poly gamedev.

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"LanuHum" <Lan### [at] yandexru> wrote:
> "Mr" <m******r******at_hotmail_dot_fr> wrote:
> > "LanuHum" <Lan### [at] yandexru> wrote:
> > > Hi! I am interested in the question: is it possible to create a thread without a
> > > mesh of triangles? We need a smooth surface of the thread in the picture
> > > 38400x21600 (4K * 10)
> >
> > Hi, Also, though it may be less physically accurate with respect to its
> > geometry,
> > this scene on Jaime Vives Piqueres site still works out of the box and features
> > a nice lighting and composition setup:
> > http://ignorancia.org/uploads/zips/boltstill.zip
> > ....If you just drop all of the lightsys macro files within the same folder :
> > http://ignorancia.org/uploads/zips/lightsys4b.zip
>
> Hi! Thanks, I saw a height_field in the file. This is a bad decision for my
> purpose. Scattering media with photons example + drum kit. 2 Up pictures from
> documentation and demo scenes. I want to create a real scene based on two
> examples from the documentation. The camera will be in different locations. In
> some cases, this spiral thread will be perfectly visible.I need clear, smooth
> lines with no signs of a low-poly gamedev.

Why do you mention low poly? it's non-mesh... also the heightfield is used only
for the head, which you don't need.
But anyway many other answers before I mentioned Jaime's offer other non-mesh
alternatives so by now, you end up having too many options, so you need more
time to just pick one of them :-P The scene will be awesome!

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