hey### [at] omabe wrote:

> hello,
> After (a lot) of trial and error I came to the attached result. There
> still is a problem with the horizon at the back: I want to soften or
> blur it to make the landscape and the sky fade into each other and
> become foggy or misty. I tried with adding fog but wasn't succesfull.
> Any help or suggestions will be appreciated.
> Thanks in advance.
> regards

Say.. where did you get the cool europe heightfield?

Simon
http://home.istar.ca/~sdevet

Post a reply to this message

thanks for the comments but the problem remains unsolved:
1. using both types of fog, I can create a more realistic scene but
there remains some detail to be seen at the horizon: the separation
between clouds and landscape is still visible. looks like I can't
create fog that is strong or dense enough to hide all details at the
horizon.
2. I did not use any spheres or other closed objects; just 2
heigthfields. so, I am not inside an hollow object.
3. complete, detailed heightfields can be downloaded from:
http://edcwww.cr.usgs.gov/landdaac/gtopo30
gtopo30 is a global digital elevation model (DEM) with a horizontal
grid spacing of 30 arc seconds (approx. 1 kilometer).
further comments are welcomed.

Post a reply to this message

On Thu, 27 Aug 1998 14:45:25 GMT, hey### [at] omabe <hey### [at] omabe> wrote:
>thanks for the comments but the problem remains unsolved:
...
>2. I did not use any spheres or other closed objects; just 2
>heigthfields. so, I am not inside an hollow object.

(By the way, please don't post binaries in this group.  That's why there are
binaries groups.)

You can be inside a heightfield, as well.  If your sky heightfield isn't 
"upside-down" you will be inside of it.  Basically, the "inside" of an 
untransformed heightfield is everything with a y value below the level of 
the surface and with 0<=x<=1 and 0<=z<=1.  Yes, everything - heightfields 
are infinite objects, despite the fact that they are documented in the 
"finite solid primitives" section of the manual.

Post a reply to this message

In article <35e587e6.0@news.povray.org>, par### [at] my-dejanewscom says...

>Yes, everything - heightfields 
>are infinite objects, despite the fact that they are documented in the 
>"finite solid primitives" section of the manual.

Interesting, I didn't knew that !  I tought their inside was limited
to the 0,1 box...  
So they're a bit like planes...

To "heylen" : the parser should give you a warning message if the
cam'ra is inside something.  But your problem may be different...

Fabien.

Post a reply to this message

Fabien Mosen wrote:

> In article <35e587e6.0@news.povray.org>, par### [at] my-dejanewscom says...
>
> >Yes, everything - heightfields
> >are infinite objects, despite the fact that they are documented in the
> >"finite solid primitives" section of the manual.
>
> Interesting, I didn't knew that !  I tought their inside was limited
> to the 0,1 box...
> So they're a bit like planes...
>
> To "heylen" : the parser should give you a warning message if the
> cam'ra is inside something.  But your problem may be different...
>
> Fabien.

I think the problem doesn't lie in some construction error, but the fact that
it isn't all that easy to create a nice blurry horizon with fog layers. I've
tried myself a few times and it was a disaster. If anyone ever succeeded in
creating a nice distant fog that blurs out the horizon, I'd be really
interested in how he/she accomplished that.

JK

Post a reply to this message

>I think the problem doesn't lie in some construction error, but the fact
that
>it isn't all that easy to create a nice blurry horizon with fog layers.
I've
>tried myself a few times and it was a disaster. If anyone ever succeeded in
>creating a nice distant fog that blurs out the horizon, I'd be really
>interested in how he/she accomplished that.
>
>JK


Yes, please do tell, i'm still at the newbie stage and will soon be
attempting to add some haze to the horizon of my current study scene.
What i'm envisioning is the addition of enough fog to obscure but not
completely eliminate the horizon line on my heightfield ground plane.
Any hints on how to accomplish this will be much appreciated. Also, i
am interested in any good sky texture hints, specifically how do i
create nice 'fluffy' cirrus clouds.

Adrian Pederson

Post a reply to this message

Adrian Pederson wrote:

> >I think the problem doesn't lie in some construction error, but the fact
> that
> >it isn't all that easy to create a nice blurry horizon with fog layers.
> I've
> >tried myself a few times and it was a disaster. If anyone ever succeeded in
> >creating a nice distant fog that blurs out the horizon, I'd be really
> >interested in how he/she accomplished that.
> >
> >JK
>
> Yes, please do tell, i'm still at the newbie stage and will soon be
> attempting to add some haze to the horizon of my current study scene.
> What i'm envisioning is the addition of enough fog to obscure but not
> completely eliminate the horizon line on my heightfield ground plane.
> Any hints on how to accomplish this will be much appreciated. Also, i
> am interested in any good sky texture hints, specifically how do i
> create nice 'fluffy' cirrus clouds.
>
> Adrian Pederson

  Greetings !

The following will attempt to show you how to read the manual
and provide you an example of using a fog to blur the horizon.
It may not be suitable to a given scene but clearly demonstrates
the desired affect. You may make your checks and money orders
out to ...

K.Tyler

camera{location<0,5,-5>look_at 5}
  light_source{<0,40,-670>rgb 1}
  sphere{<0,0,0>,1 scale <9000000,9000000,500000>inverse
  texture{pigment{bozo turbulence 0.56 colour_map {
  [0.0 0.5  colour red 0.3 green 0.3 blue 1.0
            colour red 0.3 green 0.3 blue 1.0]
  [0.5 1.0  colour red 0.3 green 0.3 blue 1.0
            colour red 1.0 green 1.0 blue 1.0]}}
  finish{ambient 0.7 diffuse 0 brilliance 1 }
  scale <300000,300000,10000>}
  texture{pigment{gradient<0,0,1>colour_map{
  [0.0 0.003 colour red 1.0 green 1.0 blue 1.0 filter 0
             colour red 1.0 green 1.0 blue 1.0 filter 0]
  [.003 .016 colour red 1.0 green 1.0 blue 1.0 filter 0
             colour red 1.0 green 1.0 blue 1.0 filter 1.0]
  [.016 1.01 colour red 1.0 green 1.0 blue 1.0 filter 1.0
             colour red 1.0 green 1.0 blue 1.0 filter 1.0]}}
  finish{ambient .7 diffuse 0 brilliance 1}
  scale <10,10,40000000>}
  translate <19.8928165,31.9178133,66.4087372>}

  fog {color  fog_type 2 fog_offset 555 fog_alt 1
  rgbf 1 transmit .5 distance 30000}

  plane{y,-150 pigment{rgb<.4,.25,.05>}finish{ambient .6}}

Post a reply to this message

>
>I think the problem doesn't lie in some construction error, but the fact that
>it isn't all that easy to create a nice blurry horizon with fog layers. I've
>tried myself a few times and it was a disaster. If anyone ever succeeded in
>creating a nice distant fog that blurs out the horizon, I'd be really
>interested in how he/she accomplished that.
>
>JK

Yes, it's quite difficult to get it right; I once had to do it with
2 layered fogs and 1 ordinary fog, playing with transmit value of the 
fog's color.
In fact, you must have one opaque fog to hide the horizon line, and
another transparent one to blend more nicely in the background...

Cheers,
Fabien.

Post a reply to this message

Try adding a ground and a sky fog with their up vectors "tilted" a little
towards the camera... can yield interesting results. BTW, HF clouds are a
great idea!

--Peter

pet### [at] usanet

Post a reply to this message

hey### [at] omabe wrote:
> 
> After (a lot) of trial and error I came to the attached result. There
> still is a problem with the horizon at the back: I want to soften or
> blur it to make the landscape and the sky fade into each other and
> become foggy or misty. I tried with adding fog but wasn't succesfull.
> Any help or suggestions will be appreciated.

I can't be sure of the way your scene is set up (scales, lighting,
etc.); providing that you're not getting a "Camera is inside a
non-hollow object" error, you should be able to use fogs to get the hazy
effect you want.  I often find it better to use a ground fog, because
this doesn't obscure too much of the clouds above the camera.  I think
the trickiest part is working out what altitude, distance, and
particularly the colour you should use.  Perhaps start with a fog_alt of
half the height of the clouds, and a distance of about 10 times this
amount.  If you want to see more of the clouds, try halving both the
fog_alt and distance values.

For your scene, I'd probably try a dark blue, say rgb <.1, .2, .3>.  A
lighter colour might make the scene look more like a soupy fog is
rolling in, while a darker colour might make the scene look more like
night.  Personally, I prefer fog colours that aren't too saturated, ie.
the red, green, and blue values are quite close together; fogs that
contain too much colour tend to look very unnatural to me.

Post a reply to this message