Forgive the weird subject of this posting, but that's as close as I get to
the origin of the problem.

I use a transparant difference to create a spherical shell. Visible through
this shell is a part of a transparant cyclinder. For some reason the rays
that pass through both objects end up with the wrong color.

The following code is a minimum example that exhibits this problem. It was
rendered with version 3.1g.watcom.win32 on Windows 95 SE.

Any ideas anybody? Am I right in the assumption that this is a bug, or am I
overlooking something obvious?

Berend Meijer

// **********************************************

// A nearly transparant vertical cyclinder ...

cylinder
{
  <0,-1,0>, <0,0,0>, 0.5
  pigment
  {
    color <1,1,1>
    filter 0.8     // <-- This seems to be (part of) the problem
  }
}

// ... with on top a nearly transparant spherical shell ...

difference
{
  sphere
  {
    <0,0.5,0>, 0.5
  }
  sphere
  {
    <0,0.5,0>, 0.49
  }
  pigment
  {
    color <1,1,1>
    filter 0.9
  }
}

// ... against a white background

plane
{
  <0,0,-1>, -2
  pigment
  {
    color <1,1,1>
  }
}

// **********************************************

light_source
{
  <3,3,0>
  color <1,1,1>
}

camera
{
  location <0,1,-3>
  look_at <0,0,0>
}

--

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Have you already tried increasing the max_trace_level value in the
global_settings block (from its default value of 5)?

-- 
#macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
],13),8)-3,10>#end blob{N(array[6]{11117333955,
7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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It was the 'overlooking something obvious'. Increasing max_trace_level does
the trick.

Thanks.

--

"Warp" <war### [at] tagpovrayorg> wrote in message
news:3bd87513@news.povray.org...
>   Have you already tried increasing the max_trace_level value in the
> global_settings block (from its default value of 5)?
>
> --
> #macro N(D,I)#if(I<6)cylinder{M()#local D[I]=div(D[I],104);M().5,2pigment{
> rgb M()}}N(D,(D[I]>99?I:I+1))#end#end#macro M()<mod(D[I],13)-6,mod(div(D[I
> ],13),8)-3,10>#end blob{N(array[6]{11117333955,
> 7382340,3358,3900569407,970,4254934330},0)}//                     - Warp -

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