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From: JRG
Subject: Re: test with depth of field
Date: 26 Aug 2001 15:11:57
Message: <3b8949fd@news.povray.org>
"Jari Juslin" <zds### [at] ikifi> ha scritto nel messaggio
news:3B8833EF.9DA81B52@iki.fi...
> JRG wrote:
> > Simple scene to test some metallic textures.
>
> Nice pic. What metals are the spheres supposed to present? The "iron"
> ones (white) look very real. The yellow ones (gold? brass?) do not look
> very good. They look more like a plastic metallic spheres hung on x-mas
> tree than real metal.

To me they look right, but de gustibus non est disputandum... ;)

>I encountered similar problems when I tried to
> create realistic antique gold texture based on your magnificent
> iridescent metal but failed miserably.

Which metal? I don't think to remember something like that.

>I think at the basic problem with
> your spheres is that they are too polished and reflective; real gold
> tends to not reflect a much, but instead it has highlights that have
> this far been resisted all my attemps to model them with POV-Ray.
> Combining strong highlites with a little different colour than the
> diffuse color of the metal and possibly using blurred reflection is my
> best guess right now.

Now that you make me notice that, I think youre right... In fact I'm using
finish_D (highly polished and reflective) from my metals.inc... the problem
here is that I have no gold here at the moment...;) BTW I think that (with
POV) it's best designing your metal textures according to the scene you're
developing. It's sad having to admit that there aren't settings which
combine physical correctness to realism at all (at least with POV)...

>
> In fact I almost came to conclusion that it's impossible to model
> real-looking gold with POV-Ray, but you guys have repeatedly proved my
> asumptations of this kind false, so I expect you to do it this time too.
> One problem with gold is that it is not possible to have a real life
> look at any golden item, that would have big smooth surfaces. I have to
> rely on few very small gold items I own and to pictures. And almost all
> the pictures are taken in studio environments, with no possibility to
> know about lighting, surroundings etc. I have also noticed, that ancient
> gold items semm to look more greenish, at least on hightlights, than
> modern gold items - is this due to differences in alloy, environment of
> the items in photographs or something completely else is something I
> have not been able to find out this far.

Normals or displacing can be handy here:


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From: JRG
Subject: Re: test with depth of field
Date: 26 Aug 2001 15:17:57
Message: <3b894b65@news.povray.org>
1024x960 maybe, to preserve aspect ratio.

"Simen Kvaal" <sim### [at] remove_mestudentmatnatuiono> ha scritto nel
messaggio news:3b890616$1@news.povray.org...
> This is a very pretty image! Any chance for a larger version, say
1280x1024?
> (hint, hint).
>
> regards,
> Simen Kvaal.
>
> "JRG" <jrg### [at] hotmailcom> wrote in message
> news:3b881e41@news.povray.org...
> > Simple scene to test some metallic textures.
> > The tiles are textured with eval_pigment (which makes things a lot
> faster),
> > and the spheres are placed with my clutter macro.
> > It's my first try with *real* focal blur, and I'm quite impressed... I
> > thought it would look grainy... and, I may be wrong, but its sampling
> method
> > looks even better than aa method 2 to me...
> >
> > Cheers,
> >
> > --
> > Jonathan
> >
>
>
>


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From: Y
Subject: Re: test with depth of field
Date: 26 Aug 2001 16:29:43
Message: <3b895c37@news.povray.org>
> >  You lost me there ... what are you evaluating ?
>
> The single color of each tile.
>
> > and ... faster than what ???
>
> Than setting the color inside the loop which places the tiles, something
> like #declare p1=0; #if (p1=0) #declare Color=red #else ...
> --
> Jonathan
>
Hmmmm ... so what is eval looking at to determine the color/texture ?
You still place the tiles but when and how do you color them ?
Sorry . . . how you are doing this still escapes me and it seems that a
decision still has to be made somewhere in the code to determine what
texture to apply . . .

An example would do me much better as then I can see it ...
would you be willing to share some simple code that demos the color
evaluation and then the coloring and placement?
Thanks.
--
Y


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From: JRG
Subject: Re: test with depth of field
Date: 27 Aug 2001 03:40:28
Message: <3b89f96c@news.povray.org>
Sorry, of course I meant 1280x960...

--
Jonathan

"Simen Kvaal" <sim### [at] remove_mestudentmatnatuiono> ha scritto nel
messaggio news:3b890616$1@news.povray.org...
> This is a very pretty image! Any chance for a larger version, say
1280x1024?
> (hint, hint).
>
> regards,
> Simen Kvaal.
>
> "JRG" <jrg### [at] hotmailcom> wrote in message
> news:3b881e41@news.povray.org...
> > Simple scene to test some metallic textures.
> > The tiles are textured with eval_pigment (which makes things a lot
> faster),
> > and the spheres are placed with my clutter macro.
> > It's my first try with *real* focal blur, and I'm quite impressed... I
> > thought it would look grainy... and, I may be wrong, but its sampling
> method
> > looks even better than aa method 2 to me...
> >
> > Cheers,
> >
> > --
> > Jonathan
> >
>
>
>


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From: JRG
Subject: Re: test with depth of field
Date: 27 Aug 2001 03:42:44
Message: <3b89f9f4@news.povray.org>
#declare tile = superellipsoid { <0.03,0.03> translate -y scale 0.5}
#declare fin =finish {diffuse 0.7 specular 0.3 roughness 0.08 reflection
0.25}

#declare mio_pig=  pigment {pigment_pattern {checker color rgb 1, color rgb
0 scale 2}
                pigment_map {
                        [0 checker color rgb <.2,.35,.55>, color rgb
<1,1,.9>]
                        [1 checker color rgb <.55,.2,.35>, color rgb
<1,1,.9>]}
}

#declare land=
union{
#declare I=seed(0);
#declare i=-30;
#while (i<=30)
#declare j=40;
#while (j>=-10)
object {tile pigment {rgb eval_pigment(mio_pig,<i,0,j>)} finish {fin}
translate <i,-0.075+rand(I)*0.05,j>}
#declare j=j-1;
#end
#declare i=i+1;
#end
}

--
Jonathan


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From: Fabien Mosen
Subject: Re: test with depth of field
Date: 27 Aug 2001 08:20:44
Message: <3b8a3b1c$1@news.povray.org>
"ben paschke" wrote :

> except for the fact that features in the blur (for example, the
> highlights on the most blurred spheres) appear to diffuse into a square
> shape due to the way pov distributes the blurring rays.
> What would be ultra nice is if pov could send out rays in a circular
> pattern or even hexagonal to mimic more closely the shape of a real
> camera's apeture.

There is a potential very interesting patch to introduce, here.
Look at this :

http://www.flarg.com/bokeh.html

That's a feature found in very high-end rendering software, and,
as far as I understand it, one just has to tweak to shape of the
distribution, and the relative weight of the samples.

Fabien.


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From: Y
Subject: Re: test with depth of field
Date: 27 Aug 2001 09:40:07
Message: <3b8a4db7@news.povray.org>
> object {tile pigment {rgb eval_pigment(mio_pig,<i,0,j>)} finish {fin}
 > --
> Jonathan
>
 Ah ha!!!  Thanks, Jonathan ...
now I can see the speed-up comes from.
Nice code.
--
Y


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From: ben paschke
Subject: Re: test with depth of field
Date: 28 Aug 2001 20:39:47
Message: <3B8C3A40.8D087E57@rsp.com.au>
Yes! I think it would be a great addition! A simple thing, yet so
effective: there's nothing like a good defocus effect.

Fabien Mosen wrote:
> 
> "ben paschke" wrote :
> 
> > except for the fact that features in the blur (for example, the
> > highlights on the most blurred spheres) appear to diffuse into a square
> > shape due to the way pov distributes the blurring rays.
> > What would be ultra nice is if pov could send out rays in a circular
> > pattern or even hexagonal to mimic more closely the shape of a real
> > camera's apeture.
> 
> There is a potential very interesting patch to introduce, here.
> Look at this :
> 
> http://www.flarg.com/bokeh.html
> 
> That's a feature found in very high-end rendering software, and,
> as far as I understand it, one just has to tweak to shape of the
> distribution, and the relative weight of the samples.
> 
> Fabien.


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