Watching a game show on TV the other night, I saw this great piece of 
jewellery: A black pearl set with diamonds. So I decided it was a good 
time to play with photons. However I'm not sure where to go, so I beg 
for help.

The image following has photons set with this:

photons {
	count 20000
	autostop 0
	jitter .4
	save_file "photons-save-load.pho"
}

However it's all too bright. The diamonds look like they're emitting a 
ton of light. How do I reduce the light so it looks real?

Cheers!
Rick Measham

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Rick Measham wrote:
> The image following has photons set with this:

Strange .. there's no image .. posting again ...

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Attachments:
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Preview of image 'blackpearl.jpg'

"Rick Measham" <rickm*at%isite.net.au> wrote in message 
news:4357ae74@news.povray.org...

    Are you sure it was a black pearl the diamonds were set into? If so, 
then I would expect a thin gold setting around the diamond to hold the 
diamond securely. If not, then they are probably Cubic Zirconia's, and glued 
in. I even doubt the latter, because no-one would glue a CZ into a black 
pearl - they're just too expensive for CZ's. (Perhaps you saw a black 
enamelled piece with diamonds - which would make more sense?)

     Nice start though. How are you going to get the lustre/sheen of a 
(black) pearl?

      ~Steve~

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Rick Measham <rickm*at%isite.net.au> wrote:
> Rick Measham wrote:
> > The image following has photons set with this:
>
> Strange .. there's no image .. posting again ...

How about a layered, Pearlescent type of texture for the pearl?
Alter the pigments and play with the specular and transmit values on the for
nice effects.
Results in nice pearlescent paint as well.


  #declare Rmin=.1;
  #declare Rmax=.33;
  #declare T_inner=White; #declare T_outer=Black;
   //#declare T_inner=White; #declare T_outer=Black;
   //#declare T_inner=Black; #declare T_outer=White;
   //#declare T_inner=Blue*0.3; #declare T_outer=Red*0.0+Green*0.9+Blue*0.9;
   //#declare c1=Red*0.5; #declare c2=Red*0.9+Green*0.9+Blue*0.0;

  #declare T_Layers=
  texture{
    pigment{rgb T_inner}
    finish{specular 2 metallic roughness .1 brilliance 10}
  }
  texture{
    pigment{rgb T_outer transmit .33}
    finish{
    specular 1 roughness .0125 diffuse 1-rmax reflection{Rmin,Rmax}
conserve_energy
    }
  }

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St. wrote:
>    Are you sure it was a black pearl the diamonds were set into? If so, 
> then I would expect a thin gold setting around the diamond to hold the 
> diamond securely.

I assume there was a thin gold setting then .. as the piece was worth 
half a small fortune!

Thanks!

Rick Measham

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Rick Measham <rickm*at%isite.net.au> wrote:
> St. wrote:
> >    Are you sure it was a black pearl the diamonds were set into? If so,
> > then I would expect a thin gold setting around the diamond to hold the
> > diamond securely.
>
> I assume there was a thin gold setting then .. as the piece was worth
> half a small fortune!
>
> Thanks!
>
> Rick Measham


Rick, how is the ambient_light's value? its may be zero..

Hasan.

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Rick Measham wrote:
>> The image following has photons set with this:

OK, here's the latest version ..

Q: How do I give an idea of the scale?

Notes:
- I've used/changed the texture provided by 'ts'
- I've changed the light to an area_light (always intended)
- I've turned off radiosity .. don't think it's really needed
- I've turned off the photons .. I like it already :)

Thoughts/Comments/Suggestions always welcome. Source available on request.

Cheers!
Rick Measham

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Attachments:
Download 'blackpearl.jpg' (22 KB)

Preview of image 'blackpearl.jpg'

> Q: How do I give an idea of the scale?
You could put it against a wooden surface with an appropriate grain, or
have a macroscopic background (maybe of a room you have done in the
past) heavily focus-blurred. You could attach a slender chain or thread
to it, or have some visible skin near it (a finger, a neck) if you are
feeling like spending a lot of time on the background.

-- 
But like the blackbird on the wire    And like the blackbird on the wire
I will not take the prey on you    [ surreal ]       I just watch you by
You wouldn't want me to            [ .istic. ]  The tears I knew I'd cry
For I am too soft for such a thing [   org   ] Fall unnoticed down below

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Daniel Hulme <pho### [at] isticorg> wrote:
> > Q: How do I give an idea of the scale?
> You could put it against a wooden surface with an appropriate grain, or
> have a macroscopic background (maybe of a room you have done in the
> past) heavily focus-blurred. You could attach a slender chain or thread
> to it, or have some visible skin near it (a finger, a neck) if you are
> feeling like spending a lot of time on the background.
you could just hang it from an ear, like the girl with a pearl earring in
this year's POVCOMP.
Now we can see the pink diamonds it's clear why it would be so expensiVe!
I would expect a black pearl to have an iridescent surface, and may be some
irregularity of shape.
Joanne
http://www.onewhiteraven.com

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Rick Measham <rickm*at%isite.net.au> wrote:
> Rick Measham wrote:

> Notes:
> - I've used/changed the texture provided by 'ts'

i may have messed up on that code Rick ...
try the following instead ...
playing with the variable "Trans" to tweak the transparency.

//------- Pearlescent Texture -----------
#declare Rmin=.1;
#declare Rmax=.33;
#declare Trans=.5; //Alter transmission of outer texture
#declare T_inner=White; #declare T_outer=Black; // *****
//#declare T_inner=Silver; #declare T_outer=Black;
//#declare T_inner=Yellow; #declare T_outer=Red; //easier to see the results
in color

#declare TOpal=
    texture{pigment{rgb T_inner} finish{specular 1 metallic roughness .1
brilliance 25}}
    texture{pigment{rgb T_outer transmit Trans}
      finish{specular 1 roughness .0125 diffuse 1-Rmax reflection{Rmin,Rmax}
conserve_energy}
    }

The attached file shows the results of using White as the inner
texture and transparent Black as the outer ...
the upper left sphere being the inner texture alone ...
then with Black at 0.9 transmit, 0.8 going left to right ...
the 2nd row down 0.7, 0.6, 0.5 ... ect all the way to 0 transparency
bottom center.
It may be easier to see if you uncomment the Yellow/Red pigment line above
....
and of course one can use Silver or even one of the Metal textures for
the inner.

I haven't tried adding a bump normal ...
not sure one can with layer textures.
and suggestions in that area would be appreciated.

> Thoughts/Comments/Suggestions always welcome. Source available on request.
>
> Cheers!
> Rick Measham

sure ... please do post the source ...
I never have done well using diamonds so ...
would appreciate if you could point me in the right direction.

-ts-

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