Hi Tracers!

Finally, by trial and error, I found out how to render the atmosphere
from orbit correctly... but now a new problem occurs.

As you can see, I used a sky sphere with stars - and all stars behind
the media-filled sphere which makes up the atmosphere appear exaggerated
in size and brightness. Is there any way to avoid this effect?

Here the POV code for the "air" in the atmosphere sphere:

#declare Air =

   material  // Air

   {

      texture

      {

         pigment

         {

            color rgbft <1.0, 1.0, 1.0, 1.0, 1.0>

         }

      }

      interior

      {

         ior 1
         media

         {

            scattering

            {

               4 ,  rgb <0.0, 0.5, 1.0> // isotropic scattering

            }

            density

            {

               spherical

            }

         }

      }

   }

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Attachments:
Download 'afghan sunrise.jpg' (133 KB)

Preview of image 'afghan sunrise.jpg'

I am not going to be much help with your problem, media just acts that way
sometimes, but I wanted Ken to note the proper way to indent and arrange
code. Especially note the double spaced close-braces at the end.


>
> #declare Air =
>
>    material  // Air
>
>    {
>
>       texture
>
>       {
>
>          pigment
>
>          {
>
>             color rgbft <1.0, 1.0, 1.0, 1.0, 1.0>
>
>          }
>
>       }
>
>       interior
>
>       {
>
>          ior 1
>          media
>
>          {
>
>             scattering
>
>             {
>
>                4 ,  rgb <0.0, 0.5, 1.0> // isotropic scattering
>
>             }
>
>             density
>
>             {
>
>                spherical
>
>             }
>
>          }
>
>       }
>
>    }
>

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sorry to spoil it for you bill, but i think he's using moray.

Bill DeWitt wrote:
> 
> I am not going to be much help with your problem, media just acts that way
> sometimes, but I wanted Ken to note the proper way to indent and arrange
> code. Especially note the double spaced close-braces at the end.
> 

> >
> > #declare Air =
> >
> >    material  // Air
> >
> >    {
> >
> >       texture
> >
> >       {
> >
> >          pigment
> >
> >          {
> >
> >             color rgbft <1.0, 1.0, 1.0, 1.0, 1.0>
> >
> >          }
> >
> >       }
> >
> >       interior
> >
> >       {
> >
> >          ior 1
> >          media
> >
> >          {
> >
> >             scattering
> >
> >             {
> >
> >                4 ,  rgb <0.0, 0.5, 1.0> // isotropic scattering
> >
> >             }
> >
> >             density
> >
> >             {
> >
> >                spherical
> >
> >             }
> >
> >          }
> >
> >       }
> >
> >    }
> >

Post a reply to this message

have you checked out any other planets people here have made?  i've done
some.  my latest (which i haven't posted) is pretty darn good in my
opinion.  i think i posted some source in p.t.s-f.  just look for my
name as the poster (postee?).  i based my atmosphere on jeff lee's
tutorial, but changed quite a few things.  i used image maps which
you'll have to replace with your own.  good luck.


> 
> Hi Tracers!
> 
> Finally, by trial and error, I found out how to render the atmosphere
> from orbit correctly... but now a new problem occurs.
> 
> As you can see, I used a sky sphere with stars - and all stars behind
> the media-filled sphere which makes up the atmosphere appear exaggerated
> in size and brightness. Is there any way to avoid this effect?
> 
> Here the POV code for the "air" in the atmosphere sphere:
> 
> #declare Air =
> 
>    material  // Air
> 
>    {
> 
>       texture
> 
>       {
> 
>          pigment
> 
>          {
> 
>             color rgbft <1.0, 1.0, 1.0, 1.0, 1.0>
> 
>          }
> 
>       }
> 
>       interior
> 
>       {
> 
>          ior 1
>          media
> 
>          {
> 
>             scattering
> 
>             {
> 
>                4 ,  rgb <0.0, 0.5, 1.0> // isotropic scattering
> 
>             }
> 
>             density
> 
>             {
> 
>                spherical
> 
>             }
> 
>          }
> 
>       }
> 
>    }
> 
>   ------------------------------------------------------------------------
>  [Image]

Post a reply to this message

news:39CCB00D.1012C1E3@ndh.net...
|
| As you can see, I used a sky sphere with stars - and all stars behind
| the media-filled sphere which makes up the atmosphere appear exaggerated
| in size and brightness. Is there any way to avoid this effect?

Try adding absorption <0.5,0.5,0.5> to media and adjust the vector to fit
what you need for color.  Also might want to try removing the transmit (rgbf
<1.0,1.0,1.0,1.0> instead) from the container pigment as well since that can
enhance background object colors causing a brightening.
This will cause a darkening of the media so scattering will need to be
changed to counteract.

Bob

Post a reply to this message

ryan constantine schrieb:

> sorry to spoil it for you bill, but i think he's using moray.
>

Yes, I in fact use Moray... it's a good aid to control whether an object is
inside the field of view or not, in "pure" POV-Ray I found that VERY difficult
to do...

But nevertheless I also feel uncomfortable with Moray in some respects,
especially when it comes to the different coordinate system (z up instead of
y...), and still there are some features (like sky spheres) which are not even
supported by the 3.2 version...

See you in Khyberspace!

Yadgar

Post a reply to this message

Bob Hughes schrieb:

> Try adding absorption <0.5,0.5,0.5> to media and adjust the vector to fit
> what you need for color.  Also might want to try removing the transmit (rgbf
> <1.0,1.0,1.0,1.0> instead) from the container pigment as well since that can
> enhance background object colors causing a brightening.
> This will cause a darkening of the media so scattering will need to be
> changed to counteract.
>

I removed the translucency statement, and the distortion of the stars
disappeared... with enhanced scattering color (I used a multiplier
factor of 10!), the media, i. e. the gradiented fringe along the
horizon, also
retained its brightness... but, whether I use your proposed amount of
absorption
or no absorption at all, now the Earth's surface appears in dull
twilight,
just as if the sun still was below the horizon (which is not, in fact,
it's about

future
versions I will rotate Earth a bit back, so that the sun actually can be
seen
(using a customized lensflare effect) slightly above the horizon).

Just increasing the sun's brightness only resulted in an "overexposure"
of the media, but not in a lit surface with realistic contrast... how to
fix
that?

See you in Khyberspace!

Yadgar

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>            color rgbft <1.0, 1.0, 1.0, 1.0, 1.0>


There's your problem.  Remove either the F or the T component.  Also, try
increasing the "diffuse" component of the planet's finish.

Mark

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I don't know if this will help, this is an adaptation from a tutorial I 
was following.  I vaguely remember some improvement in making the 
absorption media and scattering media in separate declarations.  The 
tutorial advised dividing the color statement by the scale used to match 
the radius of the atmosphere.

---code
#declare atmos = media {     file://atmospheric scatter
   scattering {4, rgb <.6,.5,1>/8280.5}
   intervals 1        file://set to 10 for final
   samples 2, 20
   confidence 0.9999
   variance 1/1000
   density {
      spherical
      color_map{ 
         [0,    rgbf <0,0,0,1>] 
         [.075, rgbf <.75, .75, .75, 1>] 
         [.15   rgbf 1] 
         [.6,   rgbf 1] 
         [.61,  rgbf <0,0,0,1>] 
         [1,    rgbf <0,0,0,1>]
      }
   }
scale 8280.5}

#declare atmos2 = media {     file://atmospheric absorption
   absorption rgb <.6, .5, 0>/8280.5
   intervals 1      file://set to 20 for final
   samples 2, 20
   confidence 0.9999
   variance 1/1000
   density {
      spherical
      color_map{ 
         [0,    rgbf <0,0,0,1>] 
         [.075, rgbf <.75, .75, .75, 1>]
         [.15   rgbf 1] 
         [.6,   rgbf 1] 
         [.61,  rgbf <0,0,0,1>]
         [1,    rgbf <0,0,0,1>]
      }
   }
scale 8280.5}

sphere {0, 8280.5 hollow    file://atmosphere upper layer (low 
refraction)
   pigment{rgbt 1.0}
   interior {ior 1.000292 media {atmos} media {atmos2}} file://050
   } 
---

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"sacrofts" <sac### [at] tinyonlinecouk> wrote in message
news:39cdbfbe@news.povray.org...
I don't know if this will help, this is an adaptation from a tutorial I was
following.  I vaguely remember some improvement in making the absorption
media and scattering media in separate declarations.  The tutorial advised
dividing the color statement by the scale used to match the radius of the
atmosphere.

Do you have the URL to that tutorial available to post here? TIA if you do
because I'm sure people will want a look.
Reason I said absorption <0.5,0.5,0.5> was because of the uncertainty about
how it would fit in to begin with, so I was really just saying try
absorption.

Bob

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