Maxime Marrow nous apporta ses lumieres en ce 2008/03/23 10:32:
> Consider the following POV-Ray code:
> 
> #include "functions.inc"
> 
> background{1}
> 
> camera {
>    location  1.5
>    look_at   0
> }
> 
> isosurface{
>  function { f_noise3d(3*x, 3*y, 3*z) - 1/2 }
> 
>  max_gradient 4
> 
>  hollow
>  pigment { rgbf 1 }
> 
>  interior{
>   media{
>    intervals 100
>    absorption 1
>   }
>  }
> }
> 
> What is the reason for the black spots and is there a way to avoid them?
> 
> Thank you,
> Maxime
Apart from the obvious isue with max_trace_level.

You may need to add "all_intersections" to your isosurface. Without that, you 
will miss most surfaces after the first one encountered.

Maybe the 100 intervals are causing some artefacts.

Try this for your media:

media{ samples 300 absorbtion 1}

This will guive you the same total number of samples as your current setting.
Should be a lot faster to.
Media defaults: method 3, samples 3, intervals 1.
Don't change intervals.
Keep samples larger than 2.
Please read about media sampling method 3, whitch is the default with all 
versions greater than 3.5.

In short, it's always beter to increase the samples that increasing the 
intervals. LOT faster, beter quality, reduction of possible artefacts.


-- 
Alain
-------------------------------------------------
An unbreakable toy is useful for breaking other toys.

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