POV-Ray : Newsgroups : povray.general : Refraction question. Server Time
1 Nov 2024 18:18:37 EDT (-0400)
  Refraction question. (Message 1 to 3 of 3)  
From: Simen Kvaal
Subject: Refraction question.
Date: 21 May 2000 14:19:54
Message: <392828ca@news.povray.org>
I have some problems with refraction. If I put an object inside another;
both transparent; the innermost turns black! When only partially inside, the
part inside still is black, but the bart outside looks fine. Here's a
detailed description:

I wanted to make an image with a glass and water inside it. The glass has
ior 1.44 and the water an ior of 1.33. The glass is a merge-thing:

merge {
    intersection { a cylinder with a smaller cylinder }  // this makes a
cylinder with one end open and kind of hollowed out; just like a real glass
("water-container".)
    torus // at the rim of the glass
    texture {
        pigment { color rgbf 1 }
        finish { some phong, no reflection }
    }
    interior { ior 1.44 }
}

And the water is placed inside:

intersection {
    a plane, tilted to make a sloped surface on the water
    a cylinder, slightly smaller than the inside of the glass
    texture { same as glass }
    interior { ior 1.33 }
}

There is a checkered gound plane, too... :)

The problem is, that although the water-object is fully visible, it is
black! Also, when I change the ior of the glass to 1, the problem still
persists. Also, when I extend the water to be higher than the glass, the
part outside the glass is fully transparent.

Things I've tried, but didn't make me any wiser:
*max_intersections increase.
*removal of the glass - water looks fine.
*transmit instead of filter (ecxactly the same results)
*render it in megapov (blind shot, there...)

I cannot figure this out, and it really makes me angry at my computer! Can
anyone explain these results or maybe solve my problem, before I smash my
screen! (nonono...I won't.)

Regards,
Simen Kvaal.


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From: Sebastian Strand
Subject: SV: Refraction question.
Date: 21 May 2000 14:43:41
Message: <39282e5d@news.povray.org>
"Simen Kvaal" <sim### [at] studentmatnatuiono> skrev i meddelandet
news:392828ca@news.povray.org...
> I have some problems with refraction. If I put an object inside another;
> both transparent; the innermost turns black! When only partially inside,
the
> part inside still is black, but the bart outside looks fine.
[snip]
>Things I've tried, but didn't make me any wiser:
> *max_intersections increase.
> *removal of the glass - water looks fine.
> *transmit instead of filter (ecxactly the same results)
> *render it in megapov (blind shot, there...)

Hmm, you haven't raised max_trace_level? If not, then I'm sure that's the
culprit...

Sebastian Strand
   E-mail: thezeb -at- bigfoot -dot- com
    URL: http://www.zeb.f2s.com/


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From: Simen Kvaal
Subject: Re: Refraction question.
Date: 21 May 2000 18:14:03
Message: <39285fab@news.povray.org>
Thank you! I read the docs about max_trace_level, and at first I didn't
catch the difference from max_intersections. This solved my problem, and
thank you and Chris Huff for pointing it out for me! :) I am _so_ happy, and
my computer screen survived once again. ;-)

Simen.

>Hmm, you haven't raised max_trace_level? If not, then I'm sure that's the
>culprit...


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