With all this talk about underwater - it would be nice to see some.  Anyone
have some old underwater scenes they'd like to post?  Give Robert some
ideas...



"Robert Jefferson" <bob### [at] mindspringcom> wrote in message
news:3921c60a@news.povray.org...
> First, sorry about the grammar.
> Second, I have not seen to many scenes underwater and was wondering how it
> was done.
>
> Actually I would like to do a scene half underwater and half above water.
> It would be of a child fishing with a pole go into the water from a boat
or
> a pier.
> Under his boat/pier is a normal size fish which is also about to be eaten
by
> a model I have of Nessy.
>
> I think it would be fun to do.
>
> See my scene of the unicorn in the appropiate group.
>
> Lastly i have 2 masters degree so please dont insult my intelligence.
>
> --
> -----------------------------------------------------
> Click here for Free Video!!
> http://www.gohip.com/freevideo/
>
> "Robert Jefferson" <bob### [at] mindspringcom> wrote in message
> news:392089d5@news.povray.org...
> > ok, how to make a pov look like it si underwater
> >
> > --
> > -----------------------------------------------------
> > Click here for Free Video!!
> > http://www.gohip.com/freevideo/
> >
> >
> >
>
>

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In article <3921c60a@news.povray.org>, "Robert Jefferson" 
<bob### [at] mindspringcom> wrote:

> First, sorry about the grammar.
> Second, I have not seen to many scenes underwater and was wondering 
> how it was done.

There have been a few, but not many. The main things seem to be some 
media for light beams and distance fading(or sometimes just fog or 
fade_color) and some way of making caustics on the ground.(a partially 
transparent plane between the ground and the light source, faked 
caustics, or photon mapping)
If the surface is visible, it is a good idea to use variable reflection.


> Actually I would like to do a scene half underwater and half above 
> water. It would be of a child fishing with a pole go into the water 
> from a boat or a pier.
> Under his boat/pier is a normal size fish which is also about to be 
> eaten by a model I have of Nessy.

First, I recommend that you get MegaPOV at 
http://nathan.kopp.com/patched.htm if you have not done so already.
It includes features like trace(), isosurfaces, angle dependant 
reflection, fade_color, media sampling types, etc, which would make this 
kind of scene much easier to do.

You could use a height field or an isosurface as the water surface, the 
isosurface would be more flexible and less memory-consuming, but slower 
and harder to use.
I would use "difference" to remove an area around the camera(a sphere or 
box would do) to simulate a waterproof barrier between the camera lens 
and the water. Otherwise, you won't get a visible waterline(since the 
camera normally exists at a point). You could use the trace() function 
to make camera placement easier.
For the under-water portion, you could use a scattering media to get 
visible light rays and either absorbing media or fade_color to get the 
effect of murkyness and to simulate the partially transparent nature of 
water.
For the water surface, the best way to get good results is by using 
angle-dependant reflection, a nearly completely transparent white 
pigment(water coloring is taken care of by the media/fade_color), some 
kind of highlight(I prefer blinn or specular), and an ior(water is 
around 1.3).
Another thing which many people forget: wet surfaces usually get darker. 
You might want to use layered textures to darken wet portions of the 
scene.
Ok, I think that was about everything, I will be working on a scene to 
demonstrate these techniques(most of which I am still experimenting 
with).


> Lastly i have 2 masters degree so please dont insult my intelligence.

Sorry if my message seemed to be insulting, I did not intend it that way.

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/

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In article <3921a079@news.povray.org>, "Chris S." 
<chr### [at] bluelectrodecom> wrote:

> However, it sounded to me as if Chris was merely mentioning a few 
> pointers to someone who may be new and/or have English as a second 
> language.

This is what I intended, some constructive criticism in a half-joking 
manner, but it obviously wasn't taken that way. :-(

-- 
Christopher James Huff - Personal e-mail: chr### [at] yahoocom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://chrishuff.dhs.org/
TAG Web page: http://tag.povray.org/

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just off the top of my head...

make a plane (the water)
make it hollow
give it some type 3 media (absorbtion or scatering)

give the plane a normal
give it variable reflection

this might work, but if you want a 1/2 in & 1/2 out of the water scene
you'll be better off with an isosurface instead of a plane...

if you want ideas look for scuba diving web sites...

Hope this helped you

Andre de Avillez

P.S. sorry if I misspelled anything ;-)

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Here is a nice non-pov reference image.
http://www.wacom.de/Art/tsevis/work3.html


-----------------------------------------------------------------------
Kari Kivisalo                                          www.kivisalo.net

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One of the best examples I have seen was Nathan O'Brians entry for the
School round of the IRTC.
You can get the zip file here:

 http://oz.irtc.org/ftp/pub/stills/1997-04-30/13school.zip

and the image here:

http://oz.irtc.org/ftp/pub/stills/1997-04-30/13school.jpg

This is very impressive, and was written for POVRay 3.1

( I apologize if this post is messed up, I seem to be having problems
with Netscape at the moment.)

Josh

Robert Jefferson wrote:

> ok, how to make a pov look like it si underwater
>
> --
> -----------------------------------------------------
> Click here for Free Video!!
> http://www.gohip.com/freevideo/

--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."

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Robert,
Check out the Ruins Round of the IRTC (www.irtc.org).  There are some pretty
good underwater effects there and the source for a few of them.

As for the Spelling and Grammer, "Sticks and stones may break my....."
Good luck on your project.
Wil Hale
Robert Jefferson <bob### [at] mindspringcom> wrote in message
news:392089d5@news.povray.org...
> ok, how to make a pov look like it si underwater
>
> --
> -----------------------------------------------------
> Click here for Free Video!!
> http://www.gohip.com/freevideo/
>
>
>

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Have you noticed that there are all those responces for this one question,
yet they don't pretain to making an under water scene.

Robert, if you want a simple, yet realistic scene try the following:

camera{
    location <0,-1,1>
    look_at <0,-1,0>
}

light_source{
    <1000,1000,1000> // Supposed to be the sun
    color <1,1,1>
}
fog{
    distance 125
    color blue 0.5
    turbulence 0.5
}

plane{
    y,0  // The water
    pigment{
        color rgbf <1,1,1,1>
    }
    interior{
        ior 1.33 // The index-of-refraction of water
        caustics 1 // To give the bright-spots on the ocean floor
    }
    hollow
}

plane{
    y,-5
    pigment{
        color <1,1,1>
    }
    hollow
}

A somewhat basic underwater scene.  If you are using POV-Ray for windows,
click the word that you don't understand and hit CTRL+F1(after you have
copied the above scene into POV-Ray).

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Brendan Orr wrote:
> 
> Have you noticed that there are all those responces for this one question,
> yet they don't pretain to making an under water scene.

<chuckle> Sometimes we enthusiastically get involved with showing off
our knowlege of the program and forget there was a real question that
needed answering. Human nature such as it is...

-- 
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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"Mike Weber" <mik### [at] pyxiscom> wrote in message
news:3921ce95@news.povray.org...
>
> With all this talk about underwater - it would be nice
> to see some.  Anyone have some old underwater
> scenes they'd like to post?  Give Robert some
> ideas...

Here's a scene I made with POV 3.0.  Just your basic fog.  There is no
surface to the water... I just moved the ship around until it looked good.

http://www.datasync.com/~ericfree/graphics/a/688.html

Eric
--------------------
http://www.datasync.com/~ericfree
--------------------
"I don't like it, and I'm sorry I ever had anything to do with it."
- Erwin Schrodinger talking about Quantum Mechanics.

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