Dear POV-Experts,

I have tried to get the helix function running --- it didn't work.
I then tried out the spiral function (f_spiral()) in the same setup -inside a
standard isosurface definition - and it worked right away as expected, so it's
not the fault of the test setup.

The best i could get out with the helix1 function was a cylinder in y-direction
when i used P3<P2 (Major < Minor radius!) unlike told in the help file.
I tried various values for P2 and P3, what changed the radius of the cylinder
but didn't have any other effect, no helix to be seen.
I also tried different values (i.e. 0.1, 0.5, 1, 2, 10) for P1 and well... no
effect.
For P4 i also tried 0 and 1 without effect.
P0=1, P5=2, P6=0;

[ f_helix1(x,y,z, P0, P1, P2, P3, P4, P5, P6) ]

Has anyone successfully created a helix with this function and can provide me
with a piece of working code or tell me what i did wrong?

Thanx and Merry Christmas

Volker

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Wasn't it Volker who wrote:
>Dear POV-Experts,
>
>I have tried to get the helix function running --- it didn't work.
>I then tried out the spiral function (f_spiral()) in the same setup -inside a
>standard isosurface definition - and it worked right away as expected, so it's
>not the fault of the test setup.
>
>The best i could get out with the helix1 function was a cylinder in y-direction
>when i used P3<P2 (Major < Minor radius!) unlike told in the help file.
>I tried various values for P2 and P3, what changed the radius of the cylinder
>but didn't have any other effect, no helix to be seen.
>I also tried different values (i.e. 0.1, 0.5, 1, 2, 10) for P1 and well... no
>effect.
>For P4 i also tried 0 and 1 without effect.
>P0=1, P5=2, P6=0;
>
>[ f_helix1(x,y,z, P0, P1, P2, P3, P4, P5, P6) ]
>
>Has anyone successfully created a helix with this function and can provide me
>with a piece of working code or tell me what i did wrong?

There's an example at
  http://www.econym.demon.co.uk/isotut/builtin1.htm#helix1

  isosurface {
    function { f_helix1(x,y,z,2,5,0.1,0.3,1,2,45) }
        max_gradient 3
        contained_by{sphere {0,1}}
        pigment {rgb .9}
  }

For some values you may need high values of max_gradient. Check the
warnings in the Messages output.

-- 
Mike Williams
Gentleman of Leisure

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Mike Williams <nos### [at] econymdemoncouk> wrote:
>
> There's an example at
>   http://www.econym.demon.co.uk/isotut/builtin1.htm#helix1
>
>   isosurface {
>     function { f_helix1(x,y,z,2,5,0.1,0.3,1,2,45) }
>         max_gradient 3
>         contained_by{sphere {0,1}}
>         pigment {rgb .9}
>   }
>
> For some values you may need high values of max_gradient. Check the
> warnings in the Messages output.
>
> --
> Mike Williams
> Gentleman of Leisure

Dear Mike,

Thanx a lot, now it works! I have no idea why it didn't work first, seems pretty
simple now.
I'll play around a bit now and see if i can get the result i wished for.

Merry Christmas and a Happy New Year!

Volker

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