POV-Ray : Newsgroups : povray.newusers : media interaction with background Server Time
30 Jul 2024 18:18:12 EDT (-0400)
  media interaction with background (Message 1 to 3 of 3)  
From: Penners
Subject: media interaction with background
Date: 19 Aug 2003 20:00:02
Message: <web.3f42b8d429ca6431382a10e70@news.povray.org>
Hi,
  When I specify a media with a specific color_map, for example in example
file "galaxy.pov", it looks fine with a black background.  However, when I
add a background to it, for example a blue sky sphere, the media changes
color.  (In this case to white).  Is there a way to keep the color of the
media as well as have a non-black background in my scene?

Thanks for any suggestions!


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From: Warp
Subject: Re: media interaction with background
Date: 19 Aug 2003 20:18:56
Message: <3f42be70@news.povray.org>
You should not post binary attachments to a non-binaries group.

  The images should be posted on povray.binaries.images

-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -


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From: Hughes, B 
Subject: Re: media interaction with background
Date: 19 Aug 2003 21:24:24
Message: <3f42cdc8@news.povray.org>
"Penners" <pen### [at] hotmailcom> wrote in message
news:web.3f42b8d429ca6431382a10e70@news.povray.org...
>   When I specify a media with a specific color_map, for example in example
> file "galaxy.pov", it looks fine with a black background.  However, when I
> add a background to it, for example a blue sky sphere, the media changes
> color.  (In this case to white).  Is there a way to keep the color of the
> media as well as have a non-black background in my scene?

You will be needing both an absorbing and emitting media of the same
pattern, which can be within the same interior statement. Make the absorbing
colors (densities) opposing the emitting ones. To do that, you can use
1-RGB_Density. Example: rgb <0.4,0.6,0.8> changed to rgb 1-<0.4,0.6,0.8> or
<0.6,0.4,0.2>.

Hopefully I've explained this correctly. I don't practice it enough and
didn't see an example in a quick search of the POV-Ray doc. However, you
should be able to locate some examples here in the povray newsgroups.

It might prove difficult to adjust intensities for the exact appearance you
want to achieve when a partly cloudy sky background is used instead of a
solid color. Meaning the values of either emission or absorption could need
raising or lowering; possibly just the overall density values.

P.S. I won't repeat what Warp said about the file attachment, except to
point you over to the group povray.frequently-asked-questions where you
should read the posting guidelines.

Bob H.


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