POV-Ray : Newsgroups : povray.newusers : Media Help Server Time
5 Nov 2024 05:22:42 EST (-0500)
  Media Help (Message 1 to 7 of 7)  
From: Buddy13
Subject: Media Help
Date: 28 Mar 2004 17:25:00
Message: <406750bc@news.povray.org>
I can't seem to get media to work properly. I want the cones of light to 
actually be visible (not too visible, but enough to give the impression 
of being slightly foggy).

I tried some stuff from the help file, and even copied the media 
statement from that "Chickens and Aliens" scene from the IRTC (with and 
without the containing sphere).

Nothing seems to make my lights visible -- although some things make the 
whole scene too murky to even see.

Code is as follows:

----snip----
media{
   intervals 5
   samples 1,5
   confidence .99
   variance 1/150
   ratio .75
   scattering { 2, rgb 1 extinction 1 }
   density {
     spherical color_map {
       [0.0 rgb 0]
       [.5 rgb .035]
       [1.0 rgb .07]
     }
   }
   density {
     bozo color_map {
       [0.0 rgb 0]
       [1.0 rgb .07]
     }
     turbulence .25
     scale .25
   }
}
----snip----

Am I doing something wrong? Perhaps I'm just retarded.

Thanks.


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From: Hughes, B 
Subject: Re: Media Help
Date: 28 Mar 2004 18:16:40
Message: <40675cd8$1@news.povray.org>
"Buddy13" <bud### [at] themappersguildcom> wrote in message
news:406750bc@news.povray.org...
>
> Nothing seems to make my lights visible -- although some things make the
> whole scene too murky to even see.

The 'spherical' pattern doesn't reach outside of a 1 unit radius, that will
need to be scaled upward to fit the bounds of your scene. Other than that, I
think you'll also need to raise the density values, so try ten times of what
they are currently.

Also, you could leave out the intervals and other settings, since the
defaults in version 3.5 usually do okay, at least until you get a look at
the media.

P.S.
Where I suggested to raise the densities: special attention for the
spherical pattern since scaling it larger will also thicken the media,
keeping in mind that media densities should be inverse to scaling. In this
case, using the values already given for the spherical part and ten times
for the bozo part should work good.

-- 
Bob H.
http://www.3digitaleyes.com


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From: Buddy13
Subject: Re: Media Help
Date: 28 Mar 2004 18:40:43
Message: <4067627b@news.povray.org>
Hughes, B. wrote:

> "Buddy13" <bud### [at] themappersguildcom> wrote in message
> news:406750bc@news.povray.org...
> 
>>Nothing seems to make my lights visible -- although some things make the
>>whole scene too murky to even see.
> 
> 
> The 'spherical' pattern doesn't reach outside of a 1 unit radius, that will
> need to be scaled upward to fit the bounds of your scene. Other than that, I
> think you'll also need to raise the density values, so try ten times of what
> they are currently.
> 
> Also, you could leave out the intervals and other settings, since the
> defaults in version 3.5 usually do okay, at least until you get a look at
> the media.
> 
> P.S.
> Where I suggested to raise the densities: special attention for the
> spherical pattern since scaling it larger will also thicken the media,
> keeping in mind that media densities should be inverse to scaling. In this
> case, using the values already given for the spherical part and ten times
> for the bozo part should work good.
> 
Thanks, I'm trying it now.


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From: Hughes, B 
Subject: Re: Media Help
Date: 28 Mar 2004 20:18:13
Message: <40677955$1@news.povray.org>
"Buddy13" <bud### [at] themappersguildcom> wrote in message
news:4067627b@news.povray.org...
> Hughes, B. wrote:
>
> > Where I suggested to raise the densities: special attention for the
> > spherical pattern since scaling it larger will also thicken the media,
> > keeping in mind that media densities should be inverse to scaling. In
this
> > case, using the values already given for the spherical part and ten
times
> > for the bozo part should work good.
> >
> Thanks, I'm trying it now.

Should be okay for camera to subject distances of around 10 units. I just
neglected to mention that before. Other scene scales will certainly need
more adjustments made.

Curiously, I think I've stumbled across a bug about spherical patterned
(only global?) media that shows itself when using a spotlight along with
sky_sphere or background color. Posting about it to the povray.general group
to get any feedback about it. Summed up, it blanks out the background where
the spotlight passes through the media.

-- 
Bob H.
http://www.3digitaleyes.com


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From: Christopher James Huff
Subject: Re: Media Help
Date: 28 Mar 2004 23:42:36
Message: <cjameshuff-CCE766.23430228032004@news.povray.org>
In article <40675cd8$1@news.povray.org>,
 "Hughes, B." <omn### [at] charternet> wrote:

> Where I suggested to raise the densities: special attention for the
> spherical pattern since scaling it larger will also thicken the media,
> keeping in mind that media densities should be inverse to scaling. In this
> case, using the values already given for the spherical part and ten times
> for the bozo part should work good.

To clarify: scaling does not affect the media density. A ray passing 
through the center of a media-filled 1-unit sphere will pass through 2 
units of media. The same ray passing through that sphere scaled to 2 
units radius will pass through 4 units of the same media, so you will 
have to halve the density to obtain the same result.

POV can't compensate automatically because the transformation may affect 
the scale differently in different directions. For instance: say you 
scale the sphere by < 1, 0.1, 1>. From the sides, the density will 
appear the same, but from the top, it will be 1/10 as thick.

-- 
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: Buddy13
Subject: Re: Media Help
Date: 29 Mar 2004 14:59:36
Message: <40688028@news.povray.org>
Hughes, B. wrote:
> "Buddy13" <bud### [at] themappersguildcom> wrote in message
> news:4067627b@news.povray.org...
> 
>>Hughes, B. wrote:
>>
>>
>>>Where I suggested to raise the densities: special attention for the
>>>spherical pattern since scaling it larger will also thicken the media,
>>>keeping in mind that media densities should be inverse to scaling. In
> 
> this
> 
>>>case, using the values already given for the spherical part and ten
> 
> times
> 
>>>for the bozo part should work good.
>>>
>>
>>Thanks, I'm trying it now.
> 
> 
> Should be okay for camera to subject distances of around 10 units. I just
> neglected to mention that before. Other scene scales will certainly need
> more adjustments made.
> 
> Curiously, I think I've stumbled across a bug about spherical patterned
> (only global?) media that shows itself when using a spotlight along with
> sky_sphere or background color. Posting about it to the povray.general group
> to get any feedback about it. Summed up, it blanks out the background where
> the spotlight passes through the media.
> 
My standard distance in this scene is 150 units back.
In this scene, I think it's close to 1unit=1inch.

Is the spherical even needed? I really don't know what I'm doing in 
regards to media, this is my first time using it. The only reason the 
spherical is there is because it was in that scene I copied it from.

I've read the documentation over and over but it's greek to me.


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From: Hughes, B 
Subject: Re: Media Help
Date: 30 Mar 2004 00:35:40
Message: <4069072c@news.povray.org>
"Buddy13" <bud### [at] themappersguildcom> wrote in message
news:40688028@news.povray.org...
> My standard distance in this scene is 150 units back.
> In this scene, I think it's close to 1unit=1inch.

When adjusting the media density, scattering, absorption, etc., the "unit"
distances will matter a lot. So try to think in terms of 1 unit being 1/10
of 10 units and 100 units being 10 times 10. Simple arithmetic for the media
/ scales correlation.

> Is the spherical even needed? I really don't know what I'm doing in
> regards to media, this is my first time using it. The only reason the
> spherical is there is because it was in that scene I copied it from.

No, not needed. Just allows for a variance from center to outer edge. If
you'd like the patterns you use for density to be uniform, or rather of one
pattern only, then don't use others in combination.

> I've read the documentation over and over but it's greek to me.

Like most things to begin with. I know what you mean though, sometimes it's
easiest to read only one little part concerning the thing you want to learn.
Other times it takes some linking up various parts together, which I think
the documentation is capable of if used right. What I do most is search it
with the keywords but that takes knowing of them first, hence the keyword
list section is great to check through what all is there. I realize this
advice might be pointless if the content itself is confusing but it's all
written in a form a got used to over the past 10 years and I think it works.
I always consider it only 90% complete anyhow, since the remaining info is
found out by asking things or looking around the internet.
:-)

-- 
Bob H.
http://www.3digitaleyes.com


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