POV-Ray : Newsgroups : povray.binaries.images : Media Wheel Server Time
13 Aug 2024 09:33:35 EDT (-0400)
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From: Tim Cook
Subject: Re: Media Wheel
Date: 2 May 2003 12:03:31
Message: <3eb296d3$1@news.povray.org>
Philippe Debar wrote:
> The order is quite nice too, with the "symmetries" well chosen. I'll 
> suggest another order which might be easier to read (or might not): 
> starting from 12 o'clock and going clockwise, I'd go
> (0, 0, 0),(0, 0,.5),(0,.5, 0),(.5, 0, 0),(.5,.5, 0),
> (.5, 0,.5),(0,.5,.5),(.5,.5,.5),...
> (if I understood correctly, symmetries will take care of the rest.)

I'm playing around with rearranging them myself now, if it
doesn't turn out well I'll try your variation...or I could
do both. ;)

> Is the the wheel of constant depth and are the media of uniform densities?

Yes.  The wheel is a cylinder with radius of 4 height 1 at 0,0,0,
the media having only the properties of scattering, emission, and/or
absorption with rgb values -0.5, 0.0, or 0.5.

> How is the light located?

The scattered light is located at 0,0,0.5 with fade distance of 1.0
and fade power of 2.0.  There is an additional non-scattering light
at 0,0,20 to provide ambient illumination, with fade distance of 0
and fade power of 1.

> Is the wheel in front of (over) the spheres?

The dot/lines are located 0.5 units over the origin at a distance
of 3.5 units.  The coloured spheres lie at z=0.

> Where do the glows come?

The scattering light is the only light source affected by media,
all glows are properties of the media through which the light is
travelling.

> Is there media outside the wheel?

No.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


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From: Anonymous
Subject: Re: Media Wheel
Date: 2 May 2003 13:00:42
Message: <3eb2a43a@news.povray.org>
"Tim Cook" <z99### [at] bellsouthnet> wrote

> Probably could arrange it in a prettier way...

Nice. Maybe something like "+/-S", "+/-E" ...etc  instead of the spheres
would be clearer.


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From: Tim Cook
Subject: Re: Media Wheel
Date: 2 May 2003 15:21:37
Message: <3eb2c541@news.povray.org>
Arranged in a prettier way.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


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From: Tim Cook
Subject: Re: Media Wheel
Date: 2 May 2003 15:22:34
Message: <3eb2c57a$1@news.povray.org>
Good god that's some hideous compression artifacting...

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


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From: Shay
Subject: Re: Media Wheel
Date: 2 May 2003 16:02:49
Message: <3eb2cee9$1@news.povray.org>
"Tim Cook" <z99### [at] bellsouthnet> wrote in message
news:3eb1e0eb@news.povray.org...
| Probably could arrange it in a prettier way...
|

That's pretty damn cool.

 -Shay


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From: Will W
Subject: Re: Media Wheel
Date: 3 May 2003 00:38:34
Message: <3eb347ca@news.povray.org>
Thank you, Tim! Seeing this is helping me understand media.

One thing I don't understand, though, is the way some of the wedges show
pronounced variations from the center outward. Especially noticeable in
red-white-red and red-green-red. Does this have something to do with the
placement of the light source?

--
Will Woodhull
Thornhenge, SW Oregon, USA
willl.at.thornhenge.net


"Tim Cook" <z99### [at] bellsouthnet> wrote in message
news:3eb2c541@news.povray.org...
> Arranged in a prettier way.

<snip>


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From: Tim Cook
Subject: Re: Media Wheel
Date: 3 May 2003 00:58:32
Message: <3eb34c78@news.povray.org>
Will W wrote:
> One thing I don't understand, though, is the way some of the wedges show
> pronounced variations from the center outward. Especially noticeable in
> red-white-red and red-green-red. Does this have something to do with the
> placement of the light source?

the light source is placed at the exact centre of the wheel, providing
the same illuminative properties to each wedge.  the red/*/red areas
are unique in the amount they increase the light that passes through
them, because they are scattering rgb -0.5 AND absorbing rbg -0.5.
what sets those three pieces apart from each other is the emission
value; green is emitting rgb 0.5, white nothing, red emitting rgb -0.5.

-- 
Tim Cook
http://home.bellsouth.net/p/PWP-empyrean

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------


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From: Will W
Subject: Re: Media Wheel
Date: 4 May 2003 11:24:21
Message: <3eb530a5@news.povray.org>
"Tim Cook" <z99### [at] bellsouthnet> wrote in message
news:3eb34c78@news.povray.org...
> Will W wrote:
<snip>
> the light source is placed at the exact centre of the wheel, providing
> the same illuminative properties to each wedge.  the red/*/red areas
> are unique in the amount they increase the light that passes through
> them, because they are scattering rgb -0.5 AND absorbing rbg -0.5.
> what sets those three pieces apart from each other is the emission
> value; green is emitting rgb 0.5, white nothing, red emitting rgb -0.5.

Ok, that helps me correct my mental model of what is going on. So what we
are seeing in this are the effects as viewed from outside the plane of the
light rays that cause the effects. Neat!


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