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From: Geoff Wedig
Subject: Glow Tutorial?
Date: 5 Feb 2001 07:38:50
Message: <3a7e9ed9@news.povray.org>
There doesn't seem to be anything on glows in the Megapov docs.  Anyone know
where I can find a tutorial?  I've got the options from various examples,
but I don't know what the various parameters do, and experimenting with
types and the like has be less than illuminating (no pun intended, really)

Also, do glows interact with other objects?  When I placed a glow in a hole
in one object, I got glow effects on the outside of the object.  Is that
supposed to happen?

Geoff


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From: Christoph Hormann
Subject: Re: Glow Tutorial?
Date: 5 Feb 2001 11:14:16
Message: <3A7ED158.8CD2A6F8@gmx.de>
Geoff Wedig wrote:
> 
> There doesn't seem to be anything on glows in the Megapov docs.  Anyone know
> where I can find a tutorial?  I've got the options from various examples,
> but I don't know what the various parameters do, and experimenting with
> types and the like has be less than illuminating (no pun intended, really)

I have some sample pictures on:

http://www.schunter.etc.tu-bs.de/~chris/pov/glow.html

but i don't know if they are useful.  

> 
> Also, do glows interact with other objects?  When I placed a glow in a hole
> in one object, I got glow effects on the outside of the object.  Is that
> supposed to happen?
> 

Yes, but using additional parameters like size and fade_power sometimes
also leads to wrong interactions.  This is a known problem.  

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Geoff Wedig
Subject: Re: Glow Tutorial?
Date: 5 Feb 2001 12:55:28
Message: <3a7ee90f@news.povray.org>
Christoph Hormann <chr### [at] gmxde> wrote:



> Geoff Wedig wrote:
>> 
>> There doesn't seem to be anything on glows in the Megapov docs.  Anyone know
>> where I can find a tutorial?  I've got the options from various examples,
>> but I don't know what the various parameters do, and experimenting with
>> types and the like has be less than illuminating (no pun intended, really)

> I have some sample pictures on:

> http://www.schunter.etc.tu-bs.de/~chris/pov/glow.html

> but i don't know if they are useful.  

They are, but only from an intuitive sense.  It seems that type 1 has a
double boundary, for lack of a better word, which is to say there is a white
area, then a colored then it drops sharply as it fades out.  T0 has a white
boundary, but fades out much more smoothly from there.  Size affects how big
and bright, radius cuts off the glow effect after a distance, and fade power
changes the sharpness of the drop off.  That's basically all I needed to
know.


>> 
>> Also, do glows interact with other objects?  When I placed a glow in a hole
>> in one object, I got glow effects on the outside of the object.  Is that
>> supposed to happen?
>> 

> Yes, but using additional parameters like size and fade_power sometimes
> also leads to wrong interactions.  This is a known problem.  

Drat.  I was afraid of that.  Can you size the glow by intensifying the
color, then, or would that not work?

Geoff


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From: Christoph Hormann
Subject: Re: Glow Tutorial?
Date: 5 Feb 2001 13:26:00
Message: <3A7EF02E.6E2722ED@gmx.de>
Geoff Wedig wrote:
> 
> They are, but only from an intuitive sense.  It seems that type 1 has a
> double boundary, for lack of a better word, which is to say there is a white
> area, then a colored then it drops sharply as it fades out.  T0 has a white
> boundary, but fades out much more smoothly from there.  

That 'double boundary' is only due to 'overexposure', meaning that the
brightness of the glow exceeds the output range.  

> [...]
> 
> > Yes, but using additional parameters like size and fade_power sometimes
> > also leads to wrong interactions.  This is a known problem.
> 
> Drat.  I was afraid of that.  Can you size the glow by intensifying the
> color, then, or would that not work?
> 

That's possible, it was the only way to influence a glow's appearance in
earlier versions.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/


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From: Marc-Hendrik Bremer
Subject: Re: Glow Tutorial?
Date: 5 Feb 2001 16:29:45
Message: <3a7f1b49@news.povray.org>
What's wrong with chapter 9.21 of the Megopov 0.6 docs? Not that long, but
it tells the basics, I think. But "glow" is indeed no keyword in the
index-list ...

Marc-Hendrik


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From: Geoff Wedig
Subject: Re: Glow Tutorial?
Date: 6 Feb 2001 07:44:19
Message: <3a7ff1a3@news.povray.org>
Marc-Hendrik Bremer <Mar### [at] t-onlinede> wrote:

> What's wrong with chapter 9.21 of the Megopov 0.6 docs? Not that long, but
> it tells the basics, I think. But "glow" is indeed no keyword in the
> index-list ...

Yeah, it doesn't show on the index, and for some reason, doing a find didn't
work.  And doing scans on object types and such wasn't helpful either.

But speaking of which, while nosing around the povray ftp site, I saw a
bunch of files for Megapov 0.7.... Is there actually going to *be* a megapov
7?  I thought we were waiting for 3.5 before creating a new megapov.

Geoff


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From: Geoff Wedig
Subject: Re: Glow Tutorial?
Date: 6 Feb 2001 08:45:03
Message: <3a7fffdf@news.povray.org>
Geoff Wedig <wed### [at] darwinepbicwruedu> wrote:

> Marc-Hendrik Bremer <Mar### [at] t-onlinede> wrote:

>> What's wrong with chapter 9.21 of the Megopov 0.6 docs? Not that long, but
>> it tells the basics, I think. But "glow" is indeed no keyword in the
>> index-list ...

> Yeah, it doesn't show on the index, and for some reason, doing a find didn't
> work.  And doing scans on object types and such wasn't helpful either.

> But speaking of which, while nosing around the povray ftp site, I saw a
> bunch of files for Megapov 0.7.... Is there actually going to *be* a megapov
> 7?  I thought we were waiting for 3.5 before creating a new megapov.

Er, um, I guess there is a 0.7... posts crossing in the wind. ;)

I see size works now.  Does transforming a glow in a union?  Doesn't say so,
so I guess probably not.

Geoff


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From: Chris Huff
Subject: Re: Glow Tutorial?
Date: 6 Feb 2001 19:09:01
Message: <chrishuff-01DFBF.19100206022001@news.povray.org>
In article <3a7fffdf@news.povray.org>, Geoff Wedig 
<wed### [at] darwinepbicwruedu> wrote:

> I see size works now.  Does transforming a glow in a union?  Doesn't say 
> so, so I guess probably not.

I'm not sure how much of the glow code I sent them was used, I had 
partially started something like this.
In the future, it will be an effect that is added to objects, and it 
behaves more like media than an object, so don't rely on it being 
transformed along with an object. (though I may add a glow_object to 
help work around this)

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


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From: Geoff Wedig
Subject: Re: Glow Tutorial?
Date: 7 Feb 2001 08:00:10
Message: <3a8146da@news.povray.org>
Chris Huff <chr### [at] maccom> wrote:

> In article <3a7fffdf@news.povray.org>, Geoff Wedig 
> <wed### [at] darwinepbicwruedu> wrote:

>> I see size works now.  Does transforming a glow in a union?  Doesn't say 
>> so, so I guess probably not.

> I'm not sure how much of the glow code I sent them was used, I had 
> partially started something like this.
> In the future, it will be an effect that is added to objects, and it 
> behaves more like media than an object, so don't rely on it being 
> transformed along with an object. (though I may add a glow_object to 
> help work around this)

Well, it works weirdly.  If I attach a glow to a declared light, with the
light in a CSG object later, the transforms on the CSG seem to affect the
glow (it travels with them), but the transforms directly on the light (in
the light statement itself, even) don't seem to.  It stays at the light's
base position.  Still, at least if the glow is transformed the same as the
light in the bounding CSG, that makes things a little bit better, since I
can do the light's transforms on the glow manually if need be.

Geoff


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