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29 Jul 2024 12:30:06 EDT (-0400)
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From: Rohan Bernett
Subject: Lens flares without third party addons
Date: 28 Jul 2002 22:01:02
Message: <web.3d44a1b0b730afe8d02c7b870@news.povray.org>
How do I make a lens flare WITHOUT using a third party addon (like CC's one
or NKFlare)?

Rohan _e_ii


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From: Peter Popov
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 03:52:39
Message: <0qs9kug6mbrfggv22l780fdkje8ahi4ob5@4ax.com>
On Sun, 28 Jul 2002 22:00:16 EDT, "Rohan Bernett" <rox### [at] yahoocom>
wrote:

>How do I make a lens flare WITHOUT using a third party addon (like CC's one
>or NKFlare)?

Make one yourself? :)

Seriously, both Nathan's and Chris' use the same technique - they use
textured discs placed very close to the camera and facing it, so that
they appear in front of all other objects. Every element of the flare
is a disk (or a triangle or a polygon). The positions and coloring are
calculated depending on the parameters you feed (flare type, flare
location, brightness, camera location etc.)

There is a way to make semi-real lens flare using photons. Basically,
you have to reconstruct the geometry of the camera (the optics system
with all its lens and the shutter etc.) and then observe the scene
through it. If you use photons, there will be visible flares in the
image. However, this is very slow, and photons do not model
diffraction so you won't get the most peculiar flare effects at all.

Hope this helps.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Simon Adameit
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 04:33:08
Message: <3d44fdc4@news.povray.org>
"Peter Popov" wrote:
>
> There is a way to make semi-real lens flare using photons. Basically,
> you have to reconstruct the geometry of the camera (the optics system
> with all its lens and the shutter etc.) and then observe the scene
> through it. If you use photons, there will be visible flares in the
> image. However, this is very slow, and photons do not model
> diffraction so you won't get the most peculiar flare effects at all.
>

Why do you have to use photons? Wouldn't it also work with simple specular
highlights?


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From: Peter Popov
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 05:30:10
Message: <6m2akucpltthqdkqgkavh3hei1pksqi90e@4ax.com>
On Mon, 29 Jul 2002 10:29:51 +0200, "Simon Adameit" <gom### [at] gmxde>
wrote:

>Why do you have to use photons? Wouldn't it also work with simple specular
>highlights?

No.

For a more precise answer... think about it, why are we using photons
at all? If specular highlights and faked caustics were enough, there
would be no need of photons. Yet there is... I am sure Nathan Kopp,
and Hendrik van Jensen before that, didn't invest years in vain.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Simon Adameit
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 06:27:44
Message: <3d4518a0@news.povray.org>
"Peter Popov" wrote:
>
> No.
>
> For a more precise answer... think about it, why are we using photons
> at all? If specular highlights and faked caustics were enough, there
> would be no need of photons. Yet there is... I am sure Nathan Kopp,
> and Hendrik van Jensen before that, didn't invest years in vain.
>

But imho lensflares aren't caustics but multiple specular reflections of a
light source.
So why do you need photons to simulate them?


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From: TinCanMan
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 08:24:22
Message: <3d4533f6$1@news.povray.org>
> But imho lensflares aren't caustics but multiple specular reflections of a
> light source.
> So why do you need photons to simulate them?
>
>

Yes you are right and it can be done but it is very time-consuming and
difficult to get the look you want to acheive using this method.  I have
done it myself.

-tgq


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From: Warp
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 08:45:05
Message: <3d4538d1@news.povray.org>
Rohan Bernett <rox### [at] yahoocom> wrote:
> WITHOUT using a third party addon (like CC's one
> or NKFlare)?

  Why?

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Christopher James Huff
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 10:10:29
Message: <chrishuff-A4D575.09032529072002@netplex.aussie.org>
In article <3d4518a0@news.povray.org>, "Simon Adameit" <gom### [at] gmxde> 
wrote:

> But imho lensflares aren't caustics but multiple specular reflections of a
> light source.
> So why do you need photons to simulate them?

Most surfaces wouldn't be directly exposed to the light, so they would 
either be in shadow or be getting transmitted light that should have 
been refracted or reflected. Highlights alone won't do the job, they 
will always look as though they come from light directly from the light 
source.

However, I never heard about doing it with photons...my idea of the 
technique was always to put a very small reflection on the lens and make 
a very bright object or a glow at the light position. That would 
simulate all the refraction and reflection and doesn't need photons.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/


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From: Peter Popov
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 10:56:13
Message: <jrlaku4gds9bjfijavt2ma99h348knn6nu@4ax.com>
On Mon, 29 Jul 2002 09:03:25 -0500, Christopher James Huff
<chr### [at] maccom> wrote:

>However, I never heard about doing it with photons...

I think Ron made one with photons.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: JRG
Subject: Re: Lens flares without third party addons
Date: 29 Jul 2002 17:59:36
Message: <3d45bac8$1@news.povray.org>
"Warp" wrote:
> Rohan Bernett <rox### [at] yahoocom> wrote:
> > WITHOUT using a third party addon (like CC's one
> > or NKFlare)?
>
>   Why?

Why not? I want to spend time on it, I don't want anyone to think that this isn't
completely work of mine, I want to be proud of it and achieving it will make me feel
godlike...


--
Jonathan.


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