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16 Nov 2024 03:25:19 EST (-0500)
  povray for reflector design? (Message 1 to 10 of 10)  
From: Gary
Subject: povray for reflector design?
Date: 28 Mar 2004 21:29:53
Message: <40678a21$1@news.povray.org>
Hi,
I am an engineer designing a solar water heater.  The design uses a 
reflector to reflect solar energy onto a tank.  I am trying to optimize 
the rflector design such that a maximum amount of energy is reflected 
onto the tank as the sun position changes throughout the day.  The 
reflector under consideration is fixed (non-tracking).

I would like to know if Povray could be useful for modeling candidate 
reflector geometries.

For example, if I define a tank object, reflector object(s), and a light 
source(the sun), will Povray not only show the light that shines 
directly on the tank from the sun, but also show the light that is 
reflected onto the tank by the reflector?

If the answer to the question above is true, than I could use a series 
of light positions to model the path of the sun through the day, and see 
the resulting reflector performance?

I am only interested in seeing the pattern of light that results from 
each candidate reflector geometry -- I do not need Povray to show light 
intensities that are exactly true to the physics.

As is probably obvious, I don't know much about Povray, but did use it 
years ago for a couple problems, and remember being favorably impressed 
by its capabilities.  I am hoping that a Povray "guru" can take a quick 
look at my problem, and tell me whether its worth relearning enough 
Povray to give it a try.

Thanks -- Gary


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From: Rafal 'Raf256' Maj
Subject: Re: povray for reflector design?
Date: 28 Mar 2004 21:40:48
Message: <Xns94BB2F8FA9419raf256com@203.29.75.35>
cre### [at] montanadslnet news:40678a21$1@news.povray.org

> I would like to know if Povray could be useful for modeling candidate 
> reflector geometries.

Yes,
 
> For example, if I define a tank object, reflector object(s), and a light 
> source(the sun), will Povray not only show the light that shines 
> directly on the tank from the sun, but also show the light that is 
> reflected onto the tank by the reflector?

yes it will, this is done by the Photons special effect.
 
> If the answer to the question above is true, than I could use a series 
> of light positions to model the path of the sun through the day, and see 
> the resulting reflector performance?

again yes, You might want to write script to calculate X,Y,Z pozition of 
sun, or input data from external file
 
> I am only interested in seeing the pattern of light that results from 
> each candidate reflector geometry -- I do not need Povray to show light 
> intensities that are exactly true to the physics.

POV will probably do both things quite accurate
 
> As is probably obvious, I don't know much about Povray, but did use it 
> years ago for a couple problems, and remember being favorably impressed 
> by its capabilities.  I am hoping that a Povray "guru" can take a quick 
> look at my problem, and tell me whether its worth relearning enough 
> Povray to give it a try.

Btw, I'm writting to Yours email from adress - me {at} raf256 [.] com (in 
case You are using anti-spam filters etc)

-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: laurent artaud[AT]free fr
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 07:27:56
Message: <4068164c$1@news.povray.org>
>>If the answer to the question above is true, than I could use a series 
>>of light positions to model the path of the sun through the day, and see 
>>the resulting reflector performance?
> 
> 
> again yes, You might want to write script to calculate X,Y,Z pozition of 
> sun, or input data from external file
>  
> 

You can use the "sunpos.inc" included in the standard POV distribution.

Regards,

-- 
Laurent ARTAUD (lau### [at] freefr)


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From: Christopher James Huff
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 08:18:01
Message: <cjameshuff-581D63.08182729032004@news.povray.org>
In article <40678a21$1@news.povray.org>, Gary <cre### [at] montanadslnet> 
wrote:

> For example, if I define a tank object, reflector object(s), and a light 
> source(the sun), will Povray not only show the light that shines 
> directly on the tank from the sun, but also show the light that is 
> reflected onto the tank by the reflector?

It can render an image of the tank with light being reflected onto it. 
With some added media, it can show the path the light takes through the 
air (the optics.pov sample scene demonstrates this). It can't compute 
the actual light intensities though...you can't get the amount of light 
that hits the tank as a single numeric value, you get a picture of the 
tank. You *could* hack that into the code, but it would require poking 
around in the photon code...it'd be easier to write a custom simulation, 
patch it into POV as a function and use the scene language as a control 
language for it. Be interesting to use a genetic algorithm...


> I am only interested in seeing the pattern of light that results from 
> each candidate reflector geometry -- I do not need Povray to show light 
> intensities that are exactly true to the physics.

In that case, POV-Ray's photon mapping ought to be sufficient.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/


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From: Rafal 'Raf256' Maj
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 08:24:28
Message: <Xns94BB9CAE7F121raf256com@203.29.75.35>
cja### [at] earthlinknet
news:cjameshuff-581D63.08182729032004@news.povray.org 

> It can't
> compute the actual light intensities though...you can't get the amount
> of light that hits the tank as a single numeric value, you get a
> picture of the tank. You *could* hack that into the code, but it would
> require poking around in the photon code...it'd be easier to write a

How about - put a camera directly above plane on with rays are reflected, 
plane have diffuse 0, it is lighten only by photons, with some camera 
tweeking (ortographic) You would probably get imge with intensity map


-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: Christopher James Huff
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 10:26:46
Message: <cjameshuff-CB4B6B.10271229032004@news.povray.org>
In article <Xns94BB9CAE7F121raf256com@203.29.75.35>,
 "Rafal 'Raf256' Maj" <spa### [at] raf256com> wrote:

> How about - put a camera directly above plane on with rays are reflected, 
> plane have diffuse 0, it is lighten only by photons, with some camera 
> tweeking (ortographic) You would probably get imge with intensity map

With high dynamic range output, this could work. However, the clipping 
done to images in the official version would throw the results off.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/


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From: Rafal 'Raf256' Maj
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 10:31:49
Message: <Xns94BBB244F753Braf256com@203.29.75.35>
cja### [at] earthlinknet news:cjameshuff-
CB4B6B.10271229032004@news.povray.org

> With high dynamic range output, this could work. However, the clipping 
> done to images in the official version would throw the results off.

I suggest rendering 2-3 images with different light_source brighness i.e. 
0.01 0.1 and 1

btw some time ago I suggest and float-text format, this is another example 
when it could be usable...

-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: Christopher James Huff
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 13:12:42
Message: <cjameshuff-EFD7C0.13130729032004@news.povray.org>
In article <Xns94BBB244F753Braf256com@203.29.75.35>,
 "Rafal 'Raf256' Maj" <spa### [at] raf256com> wrote:

> btw some time ago I suggest and float-text format, this is another example 
> when it could be usable...

Too bulky. The files would be *big*, and not really any easier to 
handle...see the recent debate on XML, text, and binary files for 
details.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: <chr### [at] tagpovrayorg>
http://tag.povray.org/


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From: Rafal 'Raf256' Maj
Subject: Re: povray for reflector design?
Date: 29 Mar 2004 13:37:33
Message: <Xns94BBD1C13EBE4raf256com@203.29.75.35>
cja### [at] earthlinknet news:cjameshuff-
EFD7C0.13130729032004@news.povray.org

> Too bulky. The files would be *big*, and not really any easier to 
> handle...see the recent debate on XML, text, and binary files for 
> details.

But there would be option - text format (with given max. precision) or 
binary format (with given format)... I ll tryto make an RFD



-- 
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics


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From: Phil Cook
Subject: Re: povray for reflector design?
Date: 30 Mar 2004 08:23:23
Message: <opr5ofiascp4ukzs@news.povray.org>
On Mon, 29 Mar 2004 08:18:27 -0500, Christopher James Huff 
<cja### [at] earthlinknet> wrote:

> In article <40678a21$1@news.povray.org>, Gary <cre### [at] montanadslnet>
> wrote:
>
> It can render an image of the tank with light being reflected onto it.
> With some added media, it can show the path the light takes through the
> air (the optics.pov sample scene demonstrates this). It can't compute

Thanks I forgot this scene existed, helped clear up some questions I was 
having understanding media, re Scattering media and photons thread in 
p.general

--
Phil

-- 
All thoughts and comments are my own unless otherwise stated and I am 
happy to be proven wrong.


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