POV-Ray : Newsgroups : povray.binaries.images : --- : Re: Server Time
18 Aug 2024 02:19:38 EDT (-0400)
  Re:  
From: Trevor Quayle
Date: 29 Aug 2001 08:31:53
Message: <3b8ce0b9@news.povray.org>
After playing with the scene for a bit I think I may have found somewhat of
an answer.
Some of the black came from the black background (you do have walls but not
on all sides, try  "background {color <1,1,1>}".  Some of the black are
artifacts from not having max_trace_level high enough (I used 100 *ulp* to
make sure there weren't any left but you can get away with lower).  After
changing these any black that's left appear to come from the glass texture
itself.  You have filter set to 0.7 so eventually, after moving through the
glass enough, the light fades to black. Try setting the filter value in your
glass texture higher (plus the other fixes mentioned) and the black should
eventually disappear (at least I was able to get it to). Unless you want
your glass to appear like that. As a side note, you may also want to try use
light fading in your glass to achieve the look you want for your glass. Good
luck


-tgq

Image 1 - no changes
Image 2 - change "background {color <1,1,1>}"
Image 3 - change "max_trace_level 100"
Image 4 - change "color rgbf <1.0, 1.0, 1.0, 0.9>" in Glass2
Bonus:
Image 5 - add   "fade_distance 3  fade_power 1" to interior of Glass2


"Paragon" <use### [at] hostcom> wrote in message news:3b8c449c@news.povray.org...
> Thank you for the reply but it seems to have not done the trick.  I tried
> taking away the reflection from the glass material as well as increasing
the
> max_trace_level but I still get the black distortions (even with very high
> max_trace_levels).  I have attached the files for the scene if anybody
> wishes to try their hand at it.
>
> -Paragon
>
> "Scott Hill" <nos### [at] nospamthanks> wrote in message
> news:3b8c2695@news.povray.org...
> > "Paragon" <use### [at] hostcom> wrote in message
> news:3b8c20d9@news.povray.org...
> > > I've been experimenting with glass and have come
> > > across some problems...
> > >                                          ...the shot glass has all
those
> > > black inconsistencies.  There are walls covering all sides
> > > of the objects, so the black is not anything reflected or
> > > refracted.
> >
> >     First off, HTML posts are frowned upon by most people round here
(yes,
> > even in the binaries groups)...
> >
> >     Now to answer your question - Whilst you are right the black bits
> aren't
> > reflections of anything in your scene, they are caused by reflection...
> try
> > removing the reflection from the glass material and the black bits
should
> > disappear...
> >     You see, what's happening is the combination of reflection and
> > refraction is causing 'total internal reflection' - where the rays POV
is
> > calculating bounce around and around inside the glass without leaving -
of
> > course POV won't do this forever - it only calculates upto a finite
amount
> > of reflections and if it hasn't calculated a colour within that number
it
> > just colors the pixel black.
> >     Fortunately you can specify how many reflections POV calculates - I
> > don't know how you do it in Moray, but you can add the following to top
of
> > your .pov file :
> >
> > global_setting { max_trace_level <level> }
> >
> >     where <level> is the number of reflections you wish it to
calculate -
> > now the only problem is you may find that you never get rid of the black
> > bits completely and the higher the value for max_trace_level you pick
the
> > longer POV will spend rendering these parts of the scene...
> > --
> > Scott Hill.
> > Software Engineer.
> > E-Mail        : sco### [at] innocentcom
> > Pandora's Box : http://www.pandora-software.com
> >
> > *Everything in this message/post is purely IMHO and no-one-else's*
> >
> >
> >
>
>
>
>
>


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