hello,

i have a very basic question.  i'm wanting to do some light
rays streaming in a window.  ken and marc and some
other good people have already given me some good tips.

although i believe that i eventually want to confine the media
inside an object, right now i'm looking at atmospheric media
with a spotlight.

my scene looked ok with regular lighting.  when i put the
media in, i got a whiteout scene, and this was true whether
the light had the media turned on or off.

my question:  what's going on?  i thought that the media would
not be seen if the light had media attenuation off.

i actually have another question:  is media different in 3.5?
is what i'm learning with 3.1 media a waste of time?  i down-
loaded the 3.5 and i'm dangerously close to loading it.  can
i run two versions at once?

thank you, miker

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MR wrote:
> 
> hello,
> 
> i have a very basic question.  i'm wanting to do some light
> rays streaming in a window.  ken and marc and some
> other good people have already given me some good tips.
> 
> although i believe that i eventually want to confine the media
> inside an object, right now i'm looking at atmospheric media
> with a spotlight.
> 
> my scene looked ok with regular lighting.  when i put the
> media in, i got a whiteout scene, and this was true whether
> the light had the media turned on or off.
> 
> my question:  what's going on?  i thought that the media would
> not be seen if the light had media attenuation off.

It is hard to trouble shoot without some code to look at, seriously.
 
> i actually have another question:  is media different in 3.5?
> is what i'm learning with 3.1 media a waste of time?  i down-
> loaded the 3.5 and i'm dangerously close to loading it.  can
> i run two versions at once?

The implementation of media in v3.5 is essentially the same as in v3.1
but it has a few extra options that produce smoother media and offers
a little better control. However, you should be able to take what you
learn in v3.1 and apply it to v3.5 without suffering too much permanent
brain damage.

Yes you can run both version if you install them in different locations
on your hard drive. If you install v3.5 over v3.1 then you lose :~)

-- 
Ken Tyler

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"MR" <a### [at] bnet> wrote in message news:3be09305$1@news.povray.org...
> hello,
>
> my question:  what's going on?  i thought that the media would
> not be seen if the light had media attenuation off.

As Ken said, hard to give an answer without seeing your code.
I was working on a similar problem a few months ago. Here's
my media code. Hope this gives you some help.

box {
 <-2.9,-0.1,2>,<1.6,3.8,5>
 pigment {rgbt 1}
 interior {
  media {
   scattering {1,rgb 0.65 extinction 0}
   method 3
   intervals 3
   samples 1,1
  }
 }
 hollow
}

light_source {
 <3,3.25,1.5>
 rgb <0.55,0.8,0.1>*0.35
 media_interaction on
}

Gail
--
*************************************************************************
* gsh### [at] monotixcoza                *   Step into the abyss,           *
* http://www.rucus.ru.ac.za/~gail/   *   and let go.          Babylon 5 *
*************************************************************************
* Just think of me as the storm before the calm     Magic: The Gathering*
*************************************************************************

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hi gail and ken,

i think i found my problem.  i didn't understand why i was seeing
atmospheric media (not in an object) with media not turned on
in the lights.  i had a room light besides the spotlight sun outside.
after several renders, i believe that i was wrong to assume that
media_interaction was off by default.  it appears that its on instead.
and because i had no specific setting for the room light, the media
was on and it was creating the whiteout.

i've read thru the tutorial that you mentioned, ken, and i've done
about 15 renders today using atmospheric media, and i'm starting
to get a feel for the very narrow use that i have for it.

the one thing i'm having trouble with is keeping the light rays
visible and still keeping some non-media light in the room.  that
doesn't surprise me... all the light ray examples i've seen were in
fairly dark scenes.  i've been playing with extinction, scattering,
light intensity, and secondary non-media interacting lighting.

my next step is to shape a transparent object where the light rays
will be and try the media inside an object.  along with several
examples from the delivered povray scenes, i'll try out your code,
gail.   as pointed out by marc, the advantage of this method is
that the foggy look is more easily confined.

thanks, miker


"MR" <a### [at] bnet> wrote in message news:3be09305$1@news.povray.org...
> hello,
>
> i have a very basic question.  i'm wanting to do some light
> rays streaming in a window.  ken and marc and some
> other good people have already given me some good tips.
>
> although i believe that i eventually want to confine the media
> inside an object, right now i'm looking at atmospheric media
> with a spotlight.
>
> my scene looked ok with regular lighting.  when i put the
> media in, i got a whiteout scene, and this was true whether
> the light had the media turned on or off.
>
> my question:  what's going on?  i thought that the media would
> not be seen if the light had media attenuation off.
>
> i actually have another question:  is media different in 3.5?
> is what i'm learning with 3.1 media a waste of time?  i down-
> loaded the 3.5 and i'm dangerously close to loading it.  can
> i run two versions at once?
>
> thank you, miker
>
>

Post a reply to this message

MR wrote:
> 
> hi gail and ken,
> 
> i think i found my problem.

The road to enlightenment can be a bumpy one but glag to hear that you
are starting to understand the process.

-- 
Ken Tyler

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hi gail,

you're sneaky!  snuck some 3.5 syntax in on me, didn't you?
hahaha.  my 3.1g doesn't much care for the media method.
i downloaded the 3.5 v7.  i guess everybody has been, subtly
or not so sublty, telling me i oughta be using it or megapov.

guess i better go for it, huh?    ;-)

thanks, miker


"Gail Shaw" <gsh### [at] monotixcoza> wrote in message
news:3be0e8ef@news.povray.org...
>
> "MR" <a### [at] bnet> wrote in message news:3be09305$1@news.povray.org...
> > hello,
> >
> > my question:  what's going on?  i thought that the media would
> > not be seen if the light had media attenuation off.
>
> As Ken said, hard to give an answer without seeing your code.
> I was working on a similar problem a few months ago. Here's
> my media code. Hope this gives you some help.
>
> box {
>  <-2.9,-0.1,2>,<1.6,3.8,5>
>  pigment {rgbt 1}
>  interior {
>   media {
>    scattering {1,rgb 0.65 extinction 0}
>    method 3
>    intervals 3
>    samples 1,1
>   }
>  }
>  hollow
> }
>
> light_source {
>  <3,3.25,1.5>
>  rgb <0.55,0.8,0.1>*0.35
>  media_interaction on
> }
>
> Gail
> --
> *************************************************************************
> * gsh### [at] monotixcoza                *   Step into the abyss,           *
> * http://www.rucus.ru.ac.za/~gail/   *   and let go.          Babylon 5 *
> *************************************************************************
> * Just think of me as the storm before the calm     Magic: The Gathering*
> *************************************************************************
>
>

Post a reply to this message

"MR" <a### [at] bnet> wrote in message news:3be2d421@news.povray.org...
> hi gail,
>
> you're sneaky!  snuck some 3.5 syntax in on me, didn't you?
> hahaha.  my 3.1g doesn't much care for the media method.
> i downloaded the 3.5 v7.  i guess everybody has been, subtly
> or not so sublty, telling me i oughta be using it or megapov.

Sorry about that. It's not 3.5, but Megapov syntax

Gail
--
*************************************************************************
* gsh### [at] monotixcoza                *   Step into the abyss,           *
* http://www.rucus.ru.ac.za/~gail/   *   and let go.          Babylon 5 *
*************************************************************************
* Just think of me as the storm before the calm     Magic: The Gathering*
*************************************************************************

Post a reply to this message