Since I do a lot of outdoor scenes I'd like it very much if there were a simple
feature like 'atmospheric perspective'. At the moment a horizontal plane will
get darker towards the horizon and this is opposite to what you might expect. It
should be simple to implement such a thing which simply makes the color get
lighter at a bigger distance. At the moment I find myself struggling with fog or
media every time and not really getting the right result. Besides fog/media can
slow down rendering whereas the other option will make almost no difference.
It'd need only one parameter which defines how light (close to white) you want
the horizon to be.
Is this a stupid idea?

Rem

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Use a light source that is far enough and your
problem should go away...

Markus

Rem wrote:
> 
> Since I do a lot of outdoor scenes I'd like it very much if there were a simple
> feature like 'atmospheric perspective'. At the moment a horizontal plane will
> get darker towards the horizon and this is opposite to what you might expect. It
> should be simple to implement such a thing which simply makes the color get
> lighter at a bigger distance. At the moment I find myself struggling with fog or
> media every time and not really getting the right result. Besides fog/media can
> slow down rendering whereas the other option will make almost no difference.
> It'd need only one parameter which defines how light (close to white) you want
> the horizon to be.
> Is this a stupid idea?
> 
> Rem

-- 

 Ich nicht eine Sekunde!!!" H. Heinol in Val Thorens

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A new feature would be difficult - every artist will want to finesse it
differently, and there's no clear one best way, even if if allowed several
parameters.

Better:  Use texture map to make the ground plane turn transparent at far
distances, letting the sky sphere (or whatever the distant background is) show
thru.   Or use scattering media in a huge torus occluding the horizon.  

Many clever solutions to the dark horizon problem may be found in the IRTC
entries - www.irtc.org


-- 
Daren Scot Wilson
dar### [at] pipelinecom 
www.newcolor.com
----
"A ship in a harbor is safe, but that is not what ships are built for"
                                            -- William Shedd

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Rem <user> wrote:
: Besides fog/media can slow down rendering

  No, fog doesn't slow down rendering considerably. Actually I think
that fog does exactly what you want. I don't see the problem.
  My understanding is that fog is as slow as, for example, a phong
highlight (if not even faster).

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

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A thin white fog is another solution.


Rem wrote:
> 
> Since I do a lot of outdoor scenes I'd like it very much if there were a simple
> feature like 'atmospheric perspective'. At the moment a horizontal plane will
> get darker towards the horizon and this is opposite to what you might expect. It
> should be simple to implement such a thing which simply makes the color get
> lighter at a bigger distance. At the moment I find myself struggling with fog or
> media every time and not really getting the right result. Besides fog/media can
> slow down rendering whereas the other option will make almost no difference.
> It'd need only one parameter which defines how light (close to white) you want
> the horizon to be.
> Is this a stupid idea?
> 
> Rem

-- 
//Spider
        [ spi### [at] bahnhofse ]-[ http://www.bahnhof.se/~spider/ ]
What I can do and what I could do, I just don't know anymore
                "Marian"
        By: "Sisters Of Mercy"

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On Tue, 23 Mar 1999 13:11:00 +0100, Rem <use### [at] ghost> wrote:

>Since I do a lot of outdoor scenes I'd like it very much if there were a simple
>feature like 'atmospheric perspective'. At the moment a horizontal plane will
>get darker towards the horizon and this is opposite to what you might expect. It
>should be simple to implement such a thing which simply makes the color get
>lighter at a bigger distance. At the moment I find myself struggling with fog or
>media every time and not really getting the right result. Besides fog/media can
>slow down rendering whereas the other option will make almost no difference.
>It'd need only one parameter which defines how light (close to white) you want
>the horizon to be.
>Is this a stupid idea?
>
>Rem

You can achieve the result you are after with a little post-
processing. Here's a possible solution:

1. Make a copy of your scene. Enclose the whole scene in a union and
give it a white pigment and ambient 1. Set a black fog so that objects
get darker with the distance.

2. Use the resulting image as a selection in a paint program (say
PhotoShop) and adjust the saturation/brightness to suit your needs

or

2. If you are a POV snob and/or you are planning to submit the picture
to the IRTC, you can achieve the same in POV. Render your picture,
render the black-and-white thing described in 1. and combine them
using POV's average pigment (as image_maps on a plane or box).

Hope this helps.



---------
Peter Popov
ICQ: 15002700

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Peter Popov wrote:
> 
> On Tue, 23 Mar 1999 13:11:00 +0100, Rem <use### [at] ghost> wrote:
> 
> >Since I do a lot of outdoor scenes I'd like it very much if there were a simple
> >feature like 'atmospheric perspective'. At the moment a horizontal plane will
> >get darker towards the horizon and this is opposite to what you might expect. It
> >should be simple to implement such a thing which simply makes the color get
> >lighter at a bigger distance. At the moment I find myself struggling with fog or
> >media every time and not really getting the right result. Besides fog/media can
> >slow down rendering whereas the other option will make almost no difference.
> >It'd need only one parameter which defines how light (close to white) you want
> >the horizon to be.
> >Is this a stupid idea?
> >
> >Rem
> 
> You can achieve the result you are after with a little post-
> processing. Here's a possible solution:
> 
> 1. Make a copy of your scene. Enclose the whole scene in a union and
> give it a white pigment and ambient 1. Set a black fog so that objects
> get darker with the distance.
> 
> 2. Use the resulting image as a selection in a paint program (say
> PhotoShop) and adjust the saturation/brightness to suit your needs
> 
> or
> 
> 2. If you are a POV snob and/or you are planning to submit the picture
> to the IRTC, you can achieve the same in POV. Render your picture,
> render the black-and-white thing described in 1. and combine them
> using POV's average pigment (as image_maps on a plane or box).
> 
> Hope this helps.
> 
> ---------
> Peter Popov
> ICQ: 15002700

Your reply is the most helpful sofar but still misses the point. What I'm asking
for is not something that can't be done in a different way, it's just meant to
make things easier and isn't that what computer are for (among other things)?
As I tried to explain I have already tried several solutions with fog,
groundfog, combinations of both and media, not getting the result I'd like while
losing a lot of time either coding or rendering.
I'll illustrate my point:
A simple groundfog won't work because everything sticking out above it would
still get darker in the distance. Normal fog would obviously not work because
where'd be the sky on a clear sunny day?
If I'd use fog I'd have to have a ground fog which gets higher when getting
further away, so I tried rotating it but even that didn't work. 
So, I tried media, but after putting in a lot of time and effort I thought:
things could/should be simpler.

Just to make things clear: I'm not worried about just a dark horizon (that's
easy) but about objects on that horizon (buildings, mountains, the Chinese wall
for all I care).

Why shouldn't POV be able to do what Rennaissance-painter already were already
doing every day? Just a bit of simple 'sfumato' to make life easier, shouldn't
be that hard? As far as I can see you'd need only one parameter, perhaps two,
but after what I've seen with the photon-thing that could hardly be an obstacle.

Actually I'm a bit amazed about the negative reactions to this simple thing. 
Well, carry on ;-)

Rem

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Rem <use### [at] ghost> writes:

> A simple groundfog won't work because everything sticking out above
> it would still get darker in the distance. Normal fog would
> obviously not work because where'd be the sky on a clear sunny day?

Huuh?  Your sky isn't on a sky_sphere, is it?  If it is, then change
it so that it is no more.  If it already isn't, then make it closer
and you'll see it through your fog.

> Actually I'm a bit amazed about the negative reactions to this
> simple thing.  Well, carry on ;-)

We just do not get the point "normal fog won't work".  It always did
for me and many of us.  Anyway, I'm pretty sure your patch would find
useful applications.  We just don't see any for now.  Maybe you could
code it, then publish it with some samples of what it could do that
fog cannot...  See how the photon patch gets rewarded :-)  Its author
has been worshipped ever since he published it.

We're not negative (well, I certainly am not), we just don't see the
use of such a thing.  Yet, I hope.

Roland.
-- 
Roland Mas

Qu'est-ce qui est petit, jaune et vachement dangereux ?
Un canari avec le mot de passe de root.

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I'm often negatively charged, but that's beside the point ;)
Sorry Roland, but you might want to try not speaking for "everyone" too
much, okay? I just now am replying here.
I get the idea behind this horizon diffusion thing I think. However, I
don't see it happening like I first thought when reading about it. See
if this is what was meant: a transmitted white gradient texture
extending from camera to most distant visible point (on landscape) with
clearest at camera and less clear at most distant reach applied to
entire scene as a whole. Similar to what was already suggested. The
"what could go wrong?" question posed by this solution(?) would be that
if any layered textures already exist it isn't going to parse (at least
I don't think it will).

P.S. to Roland. Not jumping on you, "we" know you mean well.

Roland Mas wrote:
> We're not negative (well, I certainly am not), we just don't see the
> use of such a thing.  Yet, I hope.

-- 
 omniVERSE: beyond the universe
  http://members.aol.com/inversez/homepage.htm
 mailto:inv### [at] aolcom?Subject=PoV-News

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Is your name Rem or REM... in which case do you Lucid Dream?  (and for the
ignorant, no, it's not some kind of mind-bending drug)

--
Lance.


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