I am rendering the following file and POV-Ray for Windows 3.6.0.id8.win32
and am getting really weird artifacts in the texture.  Anyone else seeing
the same thing?  Anyone have an idea of the cause?

===8<===8<===8<===8<===8<===8<===
camera{
        sky z
        location -5*y
        look_at 0
}

background{ rgb 0.5 }

#include "functions.inc"

isosurface {
    function { f_torus(x, y, z, 1.6, 0.4)-f_noise3d(x, y, z) }
    contained_by { box { -2, 2 } }
    material{ texture{ pigment{ rgb 1 }}}
}

light_source{
        <3,-3,3> color rgb 1
}
===8<===8<===8<===8<===8<===8<===

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"Alex Wollangk" <ale### [at] tdsnet> wrote in message
news:web.4101d717e7ea1bd6aed149a60@news.povray.org...
> am getting really weird artifacts in the texture.

You should use max_gradient in the isosurface. If you read the warning
message POV gives you, after rendering without it, you'll see that it
suggests what value to give that. Check the documentation for isosurface and
you'll find out more about that. A value of around 1.6 should clear it up,
although I noticed its shading still had speckles so I'm not sure what it
would take to make those go away.

Bob H.

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"Hughes, B." <bob### [at] charternet> wrote:
> You should use max_gradient in the isosurface.

Ah.  RTFM ("Read the ***** message") :)

That did it...

Although the first time I rendered it, it told me that I should use a
max_gradient of 1.549.  I set it to 1.55 and rendered again and it told me
that I needed 1.635.  Hmmm...  Setting it to 1.64 eliminated any warnings.

Thanks,

Alex

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In article <web.410267fe6a733d77aed149a60@news.povray.org> , "Alex Wollangk"
<ale### [at] tdsnet> wrote:

> Although the first time I rendered it, it told me that I should use a
> max_gradient of 1.549.  I set it to 1.55 and rendered again and it told me
> that I needed 1.635.  Hmmm...  Setting it to 1.64 eliminated any warnings.

What you get is only an estimate.  To determine the exact value to first
time would require to always render assuming an infinite maximum gradient.
Also note that the value reported may change if you render with a higher
resolution because more samples may find places in the function needing a
different maximum gradient.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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