Here is a scene I am trying to render with POV 3.1g for win 98.
No ground fog ever appears. Why? 
// Persistence of Vision Ray Tracer Scene Description File
// File: ?.pov
// Vers: 3.1
// Desc: Basic Scene Example
// Date: mm/dd/yy
// Auth: ?[esp]
//

#version 3.1;

#include "colors.inc"
#include "tex.inc" //contains the texture definition.

global_settings
{
  assumed_gamma 1.4
}
default {texture {pigment {color Red}} }
//#include "fog.inc"
fog { fog_type 2 //Layer: Layer2
    rgb <0.620, 0.000, 0.000>
    fog_offset 6
    fog_alt 0.5 //fade away rate
} //fog


// ----------------------------------------
camera
{
  location  <0.0, 0.5, -4.0>
  direction 1.5*z
  right     4/3*x
  look_at   <0.0, 0.0,  0.0>
}

sky_sphere
{
  pigment
  {
    gradient y
    color_map { [0.0 color blue 0.6] [1.0 color rgb 1] }
  }
}

light_source
{
  0*x // light's position (translated below)
  color red 1.0  green 1.0  blue 1.0  // light's color
  translate <-30, 30, -30>
}

light_source
{
  0*x // light's position (translated below)
  color red 1.0  green 1.0  blue 1.0  // light's color
  translate <30, -30, -30>
}

// ----------------------------------------

//#include "shape.inc" //has preview shape
plane { y, -1 pigment {color rgb <0.7,0.5,0.3>}}

sphere { 0.0, 1 //start of shape
    texture { Texture1 }
} //Sphere


-- 
See my Free stuff page. It compares free website providers, and
lists free internet access providers.
http://www.crosswinds.net/~robertsc/free.htm

Win98 help file loaded with hints and tips, including securing a
Win 95/98 PC in a classroom setting. VB4 help file with lots of
code and hints. 
At http://www.crosswinds.net/~robertsc/

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Put the keyword "hollow" into the sky_sphere.

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In article <39c8cb76@news.povray.org> , "Bob Hughes" 
<per### [at] aolcom?subject=PoV-News:> wrote:

> Put the keyword "hollow" into the sky_sphere.

This is nonsense.  They keyword hollow does not belong in the sky_sphere (in
fact it won't work there at all!).   sky_sphere does not have any volume, it
is infinite - otherwise you would also get the "camera in non-hollow object"
warning!   sky_spheres are explained in the POV-Ray manual.


Now to the problem. Simply add the "distance [value]" to the fog statement,
for example:

fog { fog_type 2 //Layer: Layer2
    rgb <0.620, 0.000, 0.000>
    distance  20
    fog_offset 6
    fog_alt 0.5 //fade away rate
} //fog

This will make the fog very visible.


      Thorsten

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Thank you, that worked. The help file led me to believe that
"distance" was only for type 1 fog. 

Thorsten Froehlich wrote:
> 
> In article <39c8cb76@news.povray.org> , "Bob Hughes"
> <per### [at] aolcom?subject=PoV-News:> wrote:
> 
> Now to the problem. Simply add the "distance [value]" to the fog statement,
> for example:
> 
> fog { fog_type 2 //Layer: Layer2
>     rgb <0.620, 0.000, 0.000>
>     distance  20
>     fog_offset 6
>     fog_alt 0.5 //fade away rate
> } //fog
> 
> This will make the fog very visible.
> 
>       Thorsten

-- 
See my Free stuff page. It compares free website providers, and
lists free internet access providers.
http://www.crosswinds.net/~robertsc/free.htm

Win98 help file loaded with hints and tips, including securing a
Win 95/98 PC in a classroom setting. VB4 help file with lots of
code and hints. 
At http://www.crosswinds.net/~robertsc/

Post a reply to this message

Thank you, that worked. The help file led me to believe that
"distance" was only for type 1 fog. 

Thorsten Froehlich wrote:
> 
> In article <39c8cb76@news.povray.org> , "Bob Hughes"
> <per### [at] aolcom?subject=PoV-News:> wrote:
> 
> Now to the problem. Simply add the "distance [value]" to the fog statement,
> for example:
> 
> fog { fog_type 2 //Layer: Layer2
>     rgb <0.620, 0.000, 0.000>
>     distance  20
>     fog_offset 6
>     fog_alt 0.5 //fade away rate
> } //fog
> 
> This will make the fog very visible.
> 
>       Thorsten

-- 
See my Free stuff page. It compares free website providers, and
lists free internet access providers.
http://www.crosswinds.net/~robertsc/free.htm

Win98 help file loaded with hints and tips, including securing a
Win 95/98 PC in a classroom setting. VB4 help file with lots of
code and hints. 
At http://www.crosswinds.net/~robertsc/

Post a reply to this message

Just for a try. Does 'inverse' to the plane resolve the problem as well ?

Fabien H



> Thank you, that worked. The help file led me to believe that
> "distance" was only for type 1 fog.
>
> Thorsten Froehlich wrote:
> >
> > In article <39c8cb76@news.povray.org> , "Bob Hughes"
> > <per### [at] aolcom?subject=PoV-News:> wrote:
> >
> > Now to the problem. Simply add the "distance [value]" to the fog statement,
> > for example:
> >
> > fog { fog_type 2 //Layer: Layer2
> >     rgb <0.620, 0.000, 0.000>
> >     distance  20
> >     fog_offset 6
> >     fog_alt 0.5 //fade away rate
> > } //fog
> >
> > This will make the fog very visible.
> >
> >       Thorsten
>
> --
> See my Free stuff page. It compares free website providers, and
> lists free internet access providers.
> http://www.crosswinds.net/~robertsc/free.htm
>
> Win98 help file loaded with hints and tips, including securing a
> Win 95/98 PC in a classroom setting. VB4 help file with lots of
> code and hints.
> At http://www.crosswinds.net/~robertsc/

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"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:39c8d2d0$1@news.povray.org...
| In article <39c8cb76@news.povray.org> , "Bob Hughes"
| <per### [at] aolcom?subject=PoV-News:> wrote:
|
| > Put the keyword "hollow" into the sky_sphere.
|
| This is nonsense.  They keyword hollow does not belong in the sky_sphere
(in
| fact it won't work there at all!).   sky_sphere does not have any volume,
it
| is infinite - otherwise you would also get the "camera in non-hollow
object"
| warning!   sky_spheres are explained in the POV-Ray manual.

Curiously the Scene Help doesn't mention that fact in the section The Sky
Sphere or the fog sections either from what I could see there.
I hate to lead people astray like that, sorry.  Glad you corrected me
Thorsten.
I still use sphere instead of sky_sphere so much it's second nature to add
hollow to that anyway.  Guess when I make the mistake and get the error when
putting hollow into one that I don't think twice about it and remove it.

Bob

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news:39C926BB.1B23DBF2@club-internet.fr...
| Just for a try. Does 'inverse' to the plane resolve the problem as well ?

Shouldn't.  The normal of a plane isn't flipped when the float is negative,
only when the plane normal itself is negative.  Inside and outside of a
plane remains constant otherwise.  Unless I'm wrong about that too.

Bob

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Bob Hughes wrote:

> Curiously the Scene Help doesn't mention that fact in the section The Sky
> Sphere or the fog sections either from what I could see there.

You may be suffering from one of those misconceptions that Warp has
been talking about. A sky_sphere is not a sphere object. It is more
like the background feature that has spherical pigment properties.

-- 
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/

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Thorsten Froehlich <tho### [at] trfde> wrote:
:> Put the keyword "hollow" into the sky_sphere.

: This is nonsense.  They keyword hollow does not belong in the sky_sphere (in
: fact it won't work there at all!).   sky_sphere does not have any volume, it
: is infinite - otherwise you would also get the "camera in non-hollow object"
: warning!   sky_spheres are explained in the POV-Ray manual.

  Perhaps it could be a good idea to actually TEST the suggestion between
posting it. :)

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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