An old trace, now with 75% more photons!

(I can send a 1600x1200 if you ask nicely)


Best,

    S.

-- 
Steven Pigeon, Ph. D.
ste### [at] stevenpigeoncom
ste### [at] videotronca

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Very nice, although tht quartz looks a little odd to me. Too clear and 
dark, maybe.

-Xplo

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I'm trying a trace with a lot more photons
I'll see what  it will look like.

-- 
Steven Pigeon, Ph. D.
ste### [at] stevenpigeoncom
ste### [at] videotronca
"Xplo Eristotle" <xpl### [at] infomagicnet> wrote in message 
news:424603fc@news.povray.org...
> Very nice, although tht quartz looks a little odd to me. Too clear and 
> dark, maybe.
>
> -Xplo

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Steven Pigeon wrote:

> I'm trying a trace with a lot more photons
> I'll see what  it will look like.

Lack of photons isn't the issue; the quartz is just too perfectly 
glassy. It's not uncommon for it to have cloudy parts or other 
imperfections; check out some photos (there are many online).

Of course, changing that might be more work than you want to put in, 
especially when I did identify it. ;p

Also, is it using the IOR of quartz? (I don't remember the number 
offhand, although I remember it being quite a bit higher than glass, and 
it probably wouldn't make a big difference.. but it probably should use 
quartz IOR, regardless.)

-Xplo

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Can't remember the exact IOR right now,
but I think it's closer to glass anyway. Quartz
and diamond have IOR around 2.0



-- 
Steven Pigeon, Ph. D.
ste### [at] stevenpigeoncom
ste### [at] videotronca
"Xplo Eristotle" <xpl### [at] infomagicnet> wrote in message 
news:424630d0$1@news.povray.org...
> Steven Pigeon wrote:
>
>> I'm trying a trace with a lot more photons
>> I'll see what  it will look like.
>
> Lack of photons isn't the issue; the quartz is just too perfectly glassy. 
> It's not uncommon for it to have cloudy parts or other imperfections; 
> check out some photos (there are many online).
>
> Of course, changing that might be more work than you want to put in, 
> especially when I did identify it. ;p
>
> Also, is it using the IOR of quartz? (I don't remember the number offhand, 
> although I remember it being quite a bit higher than glass, and it 
> probably wouldn't make a big difference.. but it probably should use 
> quartz IOR, regardless.)
>
> -Xplo

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Steven Pigeon nous apporta ses lumieres en ce 2005-03-27 00:58:
> Can't remember the exact IOR right now,
> but I think it's closer to glass anyway. Quartz
> and diamond have IOR around 2.0
> 
> 
> 
Quartz a little bit over 2
Diamond: 2.5

Alain

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From my Material IORs chart:
Glass, Fused Silica        1.459

Glass, Albite              1.489

Glass, Crown, Zinc         1.517
Glass                      1.51714
Glass, Crown               1.52
Quartz                     1.544
Glass, Flint (29% Lead)    1.569
Glass, Flint (light)       1.58038
Glass, Flint (medium)      1.62725
Glass, Flint (heavy)       1.65548
Glass, Flint (dense)       1.66
Glass, Flint (55% Lead)    1.669
Glass, Flint (Lanthanum)   1.8
Glass, Flint (71% Lead)    1.805
Glass, Flint (heaviest)    1.89
Glass, Arsenic Trisulfide  2.04
Diamond                    2.417

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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Tim Cook <z99### [at] bellsouthnet> wrote:
> From my Material IORs chart:

> Diamond                    2.417

Correct, so why does consts.inc still have

#declare Diamond_Ior     = 2.47;

like it has since the days of DKBTrace? :(

Attached is an Ideal-Cut diamond with correct IOR, but the photons are not
quite realistic, although it does give a rather pretty effect, IMNSHO. :)

// Persistence of Vision Ray Tracer version 3.5 Include File
// File: brilliant5.inc
// Desc: The 'brilliant' gem-cut. Parameters from "Diamond Design" by
M.Tolkowsky
// Date: 2004.5.28
// Auth: PM 2Ring
// The "Brilliant" object is centered on the Origin, with girdle in the XZ
plane.
//
// INCLUDE FILE: DO NOT RENDER DIRECTLY!

#version 3.5;

//"Brilliant" parameters from "Diamond Design" by Tolkowsky. h:height,
r:radius, a:angle
#local htable =  0.324;
#local rtable =  0.550 * .89;
#local rgird  =  1.000;
#local hpav   = -0.862;
#local hculet = hpav+1/64;

#local acrown = -34.5;
#local astar = -20;
#local agirdhi = -39;
#local agirdlo = 42.75;
#local apav = 40.75;

#local ff=.9815;        //Fudge factor. Well, you know... :)

//Create MK facets, 'phase' K. Facet 0 passes through (X,Y,0) at angle A.
//N is facet (normal) direction: 1=face up, -1=face down.
#macro Facet(K, MK, X, Y, A, N)
  #local T=radians(A);

  //Find height of plane through (X,Y,0), with angle A to +ve X-axis
  #local H=N*(Y*cos(T) - X*sin(T));

  #while (K<MK)
    plane{N*y,H rotate <A,360*K/MK,0>}
    #local K=K+1;
  #end
#end

//Brilliant cut
#local BBound = cylinder{hculet*y, htable*y, rgird}
//#local BBound = box{<-rgird,hculet,-rgird>, <rgird,htable,rgird>}

#declare Brilliant =
intersection{
  object{BBound}

  plane{y,htable}                         //Table
  Facet(0.5, 8, rtable,htable,astar, 1)   //Stars
  Facet(0.0, 8, rgird,0,acrown, 1)        //Crown
  Facet(0.5,16, rgird*ff,0,agirdhi, 1)    //Upper Girdle

  Facet(0.5,16, rgird*ff,0,agirdlo, -1)   //Lower Girdle
  Facet(0.0 ,8, 0,hpav,apav, -1)          //Pavillion
  plane{-y,-hculet}                       //Culet

  bounded_by{BBound scale 1.001}
}

//Conical Brilliant
#declare BrillCone =
merge{
  cone{0,rgird, y*htable,rtable}
  cone{y*hpav,0, 0,rgird}
}

// ----------------------------------------

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