POV-Ray : Newsgroups : povray.binaries.images : Photons, lighting, reflection... WIP Server Time
16 Aug 2024 16:16:04 EDT (-0400)
  Photons, lighting, reflection... WIP (Message 1 to 9 of 9)  
From: Tim Nikias
Subject: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 14:40:19
Message: <3C4DBFF5.7847E30D@gmx.de>
Hi there!

I'm working on an image which should finally appear to be
photo-realistic,
but yet abstract.
The object is supposed to be made of something like gold or... erm.
Don't
know the translation of the metal that looks similiar...
So, on the object I'm playing with variable reflection, using falloff
and exponent.
The highlights are caused by the actual lightsource-object (the
media-sphere),
there is no specular or phong highlighting in the finish-statement.

The light is a high rgb area-light (using rgb 8 in this one, I think),
but with a low
fade_distance to diminish the lighting quickly. Sadly, the photons are
pretty bright
because of this too, so does someone know a trick to have a low-rgb
lightsource
shoot the photons, while another lightsource does the actual lighting?
Or am I totally wrong and photons don't care if the rgb is 8?

The floor also needs some work, but for now, I want to focus on lighting

and the object's textures. So, gimme comments, suggestions and critics!

Tim
--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: JRG
Subject: Re: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 14:50:15
Message: <3c4dc277@news.povray.org>
"Tim Nikias" <tim### [at] gmxde> ha scritto nel messaggio
news:3C4DBFF5.7847E30D@gmx.de...
> Hi there!
>
> I'm working on an image which should finally appear to be
> photo-realistic,
> but yet abstract.

Very nice.

> The object is supposed to be made of something like gold or... erm.
> Don't
> know the translation of the metal that looks similiar...

Hmm, brass?

> So, on the object I'm playing with variable reflection, using falloff
> and exponent.
> The highlights are caused by the actual lightsource-object (the
> media-sphere),
> there is no specular or phong highlighting in the finish-statement.

The highlights look pretty good imo.

> The light is a high rgb area-light (using rgb 8 in this one, I think),
> but with a low
> fade_distance to diminish the lighting quickly. Sadly, the photons are
> pretty bright
> because of this too, so does someone know a trick to have a low-rgb
> lightsource
> shoot the photons, while another lightsource does the actual lighting?
> Or am I totally wrong and photons don't care if the rgb is 8?

Now, perhaps I'm totally wrong, but I believe that all those settings that Kari and
others suggested you work best with radiosity (and assumed_gamma 1).
But have to admit I like the dim lighting of this one.

> --
> Tim Nikias
> Homepage: http://www.digitaltwilight.de/no_lights/index.html
>
>

#local j=text{ttf"arial""JRG".2,0}#local J=0;#while(J<10)#local R=0;#while
(R<2)#local G=0;#while(G<1)#if(inside(j<R,G.1>))object{j scale.025translate
<R-1G-J/20J/-40+2>pigment{rgb<9J>}}#debug"O"#else#debug" "#end#local G=G+
.025;#end#local R=R+.05;#debug"\n"#end#local J=J+1;#end// JRG

Home: http://digilander.iol.it/jrgpov  //New: Kitchen scene WIP


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From: Tim Nikias
Subject: Re: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 15:14:40
Message: <3C4DC80B.5E7194DF@gmx.de>
>
> Very nice.
>

Thanks

> Hmm, brass?
>

That'd be it!

>
> The highlights look pretty good imo.
>

Thanks again.

>
> Now, perhaps I'm totally wrong, but I believe that all those settings that Kari and
> others suggested you work best with radiosity (and assumed_gamma 1).
> But have to admit I like the dim lighting of this one.
>

Now I don't get the actual sense of this sentence: should I use
the "settings Kari and others suggested", or should I go for
radiosity (since they didn't mention that)?

Also, something strange occured on my in a test: I had colored
reflections, and then, all of a sudden, the colors wheren't in
shades of <.7,.4,0>^x, but instead also blues (no where's
the blue in <.7,.4,0>?). I do want to look at it more closely,
but since the lightsource has some blue in it, that might be
why...


--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: JRG
Subject: Re: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 15:31:56
Message: <3c4dcc3c@news.povray.org>
"Tim Nikias" <tim### [at] gmxde> ha scritto nel messaggio
news:3C4DC80B.5E7194DF@gmx.de...
> Now I don't get the actual sense of this sentence: should I use
> the "settings Kari and others suggested", or should I go for
> radiosity (since they didn't mention that)?

Yes, the sentence was badly written. I meant the "settings that Kari and others
suggested_you", work best etc..

Using very bright lightsources with pretty 'short' fade distance is a technique
generally used with (high quality) radiosity. I think that Kari thought you were
going to use it (but, as I said, I may be wrong).

> Also, something strange occured on my in a test: I had colored
> reflections, and then, all of a sudden, the colors wheren't in
> shades of <.7,.4,0>^x, but instead also blues (no where's
> the blue in <.7,.4,0>?). I do want to look at it more closely,
> but since the lightsource has some blue in it, that might be
> why...

Might be... Are you using reflection {metallic}, or are you explicitly using coloured
reflections?


--
#local j=text{ttf"arial""JRG".2,0}#local J=0;#while(J<10)#local R=0;#while
(R<2)#local G=0;#while(G<1)#if(inside(j<R,G.1>))object{j scale.025translate
<R-1G-J/20J/-40+2>pigment{rgb<9J>}}#debug"O"#else#debug" "#end#local G=G+
.025;#end#local R=R+.05;#debug"\n"#end#local J=J+1;#end// JRG

Home: http://digilander.iol.it/jrgpov  //New: Kitchen scene WIP


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From:
Subject: Re: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 15:33:38
Message: <3c4dcca2@news.povray.org>
> Hi there!

Hi Tim,

> because of this too, so does someone know a trick to have a low-rgb
> lightsource
> shoot the photons, while another lightsource does the actual lighting?
> Or am I totally wrong and photons don't care if the rgb is 8?

Well, I don't know with which POV version you're working but in Pov Demo3.5
you can choose if a light source should be a photon source or not. In this
case you may add two light sources: a dim one which is a photon source and
the bright one which does the rest but has photons turned off.
See the documentation "photons and light_sources".

If you are working with something else then sorry, I don't know.

Anyway the object looks nice. Like made of brass. For gold put more yellow
in the texture (by reducing red)
Do you have a special purpose for this object or is it just because?

regards
SY


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From:
Subject: Re: Photons add-on
Date: 22 Jan 2002 15:36:41
Message: <3c4dcd59$1@news.povray.org>
AFAIK does the rgb vector of a light source not influence the number of
photons. You declare in the global_settings section how many photons you
would like to be present and spread over the photon target(s). The
"strength" depends on the density of photons on the target surfaces.

regards
sy


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From: Tim Nikias
Subject: Re: Photons, lighting, reflection... WIP
Date: 22 Jan 2002 16:40:36
Message: <3C4DDC30.8B32FAB5@gmx.de>
I am using reflection{ metallic }, but I will render a version
with that tomorrow, as of right now, bedtime has arrived...

Gotta stand up early!

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Tim Nikias
Subject: Re: Photons add-on
Date: 22 Jan 2002 16:44:34
Message: <3C4DDD1D.9E63D746@gmx.de>
I am using POV-Ray3.5 Beta, OF COURSE... It's just the
best you can get (I still think some 1000$ aren't up to
what POV can do, and does!).

You are right about switching lights with photons and
without, but I think you are right, it depends on
density (at least that what it looks like to me during all
those smaller test-renders I'm doing), not on rgb. So
there is no need for two lightsources.
Thanks anyway.

Yup, the object is made of brass (at least its supposed to
be, you never know... ;) and its something a brother
of mine made in some manufacturing practicum
(though not as clean and polished...).

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html


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From: Hugo
Subject: Re: Photons add-on
Date: 22 Jan 2002 17:04:02
Message: <3c4de1d2$1@news.povray.org>
> I am using POV-Ray3.5 Beta, OF COURSE... It's just the
> best you can get (I still think some 1000$ aren't up to
> what POV can do, and does!).

Glad to see someone talks positive about Pov. I agree with your statement.
According to radiosity I don't think it's necessary for you to use it, when
you have blurred reflective surfaces. You'll need a high quality radiosity
for an object like this, and it's gonna take lots of render time.

Hugo


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