Hello!

Yesterday I got an idea I wanted to try in povray. A glass bowl containing
some blue liquid.

I made the bowl easily:

difference {
   sphere <0, 0, 0>, 1
   sphere <0, 0, 0>, 0.98
  ...and a plane to cut the top off...
  texture { T_Glass3 }
}

and then I made the 'liquid' in a similar way (one sphere with radius 0.98
and cut the top off with a plane).

However.. When looking at this 'bowl' I see the grayish color I set the bowl
to have, but eventhough it is transparent, I cannot see the 'blue liquid
object' through it.

It I remark the 'bowl' and only render the 'liquid' object, it looks great.

When I look at the object from 'above' it looks as it should.


Am I missing something?

Dan Farmer has made glass truely transparent in his Wg6.pov, Why can't I?
(The answer being pretty obvious :-)

Any ideas?


(Btw, using povray3)



 /j

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A problem of coinciding surfaces?

Try making your "liquid" sphere a bit smaller than 0.98 (like 0.979)

Just a guess,
Johannes.

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Jan Danielsson <Jan### [at] falunmailteliacom> wrote:
: However.. When looking at this 'bowl' I see the grayish color I set the bowl
: to have, but eventhough it is transparent, I cannot see the 'blue liquid
: object' through it.

  The coinciding surfaces -problem. Leave a 0.00001 sized space between
the glass and the liquid.

-- 
                                                              - Warp. -

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"Jan Danielsson" <Jan### [at] falunmailteliacom> writes:

> Hello!
> 
> Yesterday I got an idea I wanted to try in povray. A glass bowl containing
> some blue liquid.
> 
> I made the bowl easily:
> 
> difference {
>    sphere <0, 0, 0>, 1
>    sphere <0, 0, 0>, 0.98
>   ...and a plane to cut the top off...
>   texture { T_Glass3 }
> }
> 
> and then I made the 'liquid' in a similar way (one sphere with radius 0.98
> and cut the top off with a plane).
> 
> However.. When looking at this 'bowl' I see the grayish color I set the bowl
> to have, but eventhough it is transparent, I cannot see the 'blue liquid
> object' through it.
> 
> It I remark the 'bowl' and only render the 'liquid' object, it looks great.
> 
> When I look at the object from 'above' it looks as it should.

IMO this is not the 'coincing surfaces problem' (but you should avoid them
anyway). I suppose you have to change the max_trace_level. See section 7.8.6
of the docs. The default value is five and therefore too small: four 
intersections with the glass object and two more with the liquid.

I hope this helps

ThW

-- 
Tho### [at] uni-konstanzde
http://www.informatik.uni-konstanz.de/~willhalm/
Tschieses lavs ju

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Jan Danielsson wrote:

> Hello!
> Yesterday I got an idea I wanted to try in povray. A glass bowl containing
> some blue liquid.
> Any ideas?
> (Btw, using povray3)

  Not wanting to beat a dead horse too many more times But! With the rich
programing language and amazing diversity of PovRay there are always different
ways of getting from here to there.
For example:

  merge{
  difference{
  sphere{y*0,50}
  sphere{y*0,49.99 inverse}clipped_by{plane{y,5}}
  texture{Glass pigment{Yellow filter 1}finish{ambient .6}}}
  sphere{y*0,49.999 clipped_by{plane{y,-10}}
  texture{Glass pigment{Orange filter 1}finish{ambient .6}}}}

  plane{y,-50 pigment{rgb 1}}
  plane{y, 50 pigment{rgb 1}}
  light_source{<0,0,0>color White}
  camera{location -290*z look_at y*0}

 Instead of reducing the size of your "liquid" object try over sizing it just a
scunch and use the often overlooked merge CSG function. What with spherical
abhorration and the physical characteristics of
refraction I believe you'll never detect the slight demarcation line produced by
minimal over sizing.

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