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From: Chuck Roberts
Subject: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 08:43:30
Message: <39C21963.20239AE9@alleganisd.org>
Would someone mind commenting on this? I want to be accurate as I
can for the ranges of POV commands. 

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<html>
<head>
<title>POV command reference</title>
<meta name="keywords" content="">
<body>
<h3 align=center>POV texture command reference</h3>

<br clear=left>
<br clear=left>
<br clear=left>
<br clear=left>

A practical minimum (or practical maximum), as used here, means,
if the user exceeded this limit, the differences in the
appearance of the image would be negligible. 
<p><u>Data types</u>
<p>Data types can be: 
<ul>
<li>choice: parameter is limited to 2 or more choices. Choices
can be a numeric or a letter. All choices are listed in the
"practical min" column.
<li>color: a color in one of the following formats:
"rgbft<a,b,c,d,e>"; "color Red"; "NamedColor".
<li>float: a decimal number
<li>integer: a number without a decimal
<li>vector: in the format: <a, b, c> or just a. Each number is a
float. If the format is "a", that is equivalent to <a, a,
a>.
</ul>

<p>+ = almost infinity
<p>
<table border=1>
<tr><th>command <th>data type<th>practical min <th>practical
max<th> Notes
<tr><td><b>PIGMENTS</b><td><td><td>
<tr><td>color map amount<td>float<td>0.0<td>1.0
<tr><td>rgbtf<td>vector<td>0.0<td>1.0

<tr><td><b>PATTERNS</b><td><td><td>
<tr><td>agate_turb<td>vector<td>0.0<td>1.0
<tr><td>bump_size<td>float<td>0.0<td>5.0
<tr><td>interpolate<td>choice<td>2,4<td>
<tr><td>mandel iterations<td>float<td>0.0<td>+
<tr><td>pattern amount<td>float<td>0.0<td>1.0
<tr><td>quilt control0 and control1<td>float<td>0.0<td>1.0
<tr><td>spiral1, spiral2<td>integer<td>1<td>+
<tr><td>turbulence<td>vector<td>0.0<td>1.0

<tr><td><td><td><td>
<tr><td><td><td><td>

<tr><td><b>FINISH</b><td><td><td>
<tr><td>ambient<td>float<td>0.0<td>1.0
<tr><td>brilliance<td>float<td>1.0<td>10.0
<tr><td>diffuse<td>float<td>0.0<td>1.0
<tr><td>irid<td>float<td>0.0<td>1.0
<tr><td>irid thickness<td>float<td>0.0<td>1.0
<tr><td>irid turbulence<td>vector<td>0.0<td>10.0
<tr><td>metallic<td>float<td>0.0<td>1.0?
<tr><td>phong<td>float<td>0.0<td>1.0
<tr><td>phong_size<td>float<td>1.0<td>250.0
<tr><td>reflection<td>float<td>0.0<td>1.0
<tr><td>reflection_exponent<td>float<td>0.0<td>5.0<td>Requires
reflection_amount.
<tr><td>roughness<td>float<td>0.0<td>1.0 <td>Requires specular.
<tr><td>specular<td>float<td>0.0<td>1.0

<tr><td><td><td><td>
<tr><td><td><td><td>


<tr><td><b>GENERAL</b><td colspan=3>Commands used in multiple
places.<td><td>
<tr><td>blackhole falloff <td>float<td>0.0<td>100.0
<tr><td>blackhole radius<td>float<td>0.0<td>+
<tr><td>blackhole strength<td>float<td>0.0<td>+
<tr><td>frequency<td>float<td>0.0<td>1.0
<tr><td>lambda<td>float<td>1.0<td>100.0
<tr><td>octaves<td>integer<td>1<td>10
<tr><td>omega<td>float<td>0.0<td>10.0
<tr><td>phase<td>float<td>0.0<td>1.0
<tr><td>rotate<td>vector<td>0.0<td>1.0
<tr><td>scale<td>vector<td>0.0<td>1.0
<tr><td>translate<td>vector<td>0.0<td>1.0

<tr><td><td><td><td>
<tr><td><td><td><td>
<tr><td><td><td><td>

<tr><td><b>INTERIOR/MEDIA</b><td><td><td>
<tr><td>absorption<td>color<td><td>
<tr><td>caustics<td>float<td>0.0<td>10.0
<tr><td>confidence<td>float<td>0.0<td>1.0
<tr><td>eccentricity <td><td><td><td>Requires scatter type 5.
<tr><td>emission<td>color<td><td>
<tr><td>extinction <td>float<td>0.0<td>1.0<td>Requires any
scatter type.
<tr><td>fade_distance<td>float<td>0.0<td>100.0
<tr><td>fade_power<td>float<td>1.0<td>10.0
<tr><td>intervals<td>integer<td>1<td>+
<tr><td>ior<td>float<td>0.0<td>10.0
<tr><td>ratio<td>float<td>0.0<td>1.0<td>Ratio of lit to unlit
areas. .9 = 90% lit.
<tr><td>sample_min<td>integer<td>1<td>+
<tr><td>sample_max<td>integer<td>1<td>+
<tr><td>scatter_type <td>choice<td>1,2,3,5<td>
<tr><td>variance<td>float<td>0.0<td>1.0<td>If the variance is
below this threshold, then no more sampling is needed.

<tr><td><td><td><td>
<tr><td><td><td><td>
<tr><td><td><td><td>
<tr><td><td><td><td>


</table>
</body>
</html>

-- 
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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From: Warp
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 09:57:09
Message: <39c22ab4@news.povray.org>
Chuck Roberts <cro### [at] alleganisdorg> wrote:
: <li>color: a color in one of the following formats:
: "rgbft<a,b,c,d,e>"; "color Red"; "NamedColor".

  A color can also be "rgb <a,b,c>", "rgbf <a,b,c,d>" or "rgbt <a,b,c,d>".

  You should use < and >

: <li>float: a decimal number

  It can also be: A float in the format: <base>e<exponent>, eg. -1.23e-10,
a float identifier and the return value of a float function.

: <li>vector: in the format: <a, b, c> or just a. Each number is a
: float. If the format is "a", that is equivalent to <a, a,
: a>.

  A vector can also be two, four and five-dimensional.

: <tr><td>rgbtf<td>vector<td>0.0<td>1.0

  A color component can be larger than 1 and smaller than 0 and still have
a desired and considerable effect in the scene.

: <tr><td>turbulence<td>vector<td>0.0<td>1.0

  There's no reason why one should limit the turbulence value to 0-1. Negative
values and values larger than 1 can have a desired effect.

: <tr><td>ambient<td>float<td>0.0<td>1.0

  Setting the ambient and similar values larger than 1 can have a considerable
effect with things like fog, media, radiosity, etc.

  Some values (such as 100.0) seem quite arbitrarily chosen. Where did you
get those values?

-- 
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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From: Christoph Hormann
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:00:03
Message: <39C22B64.68264876@schunter.etc.tu-bs.de>
Chuck Roberts wrote:
> 
> Would someone mind commenting on this? I want to be accurate as I
> can for the ranges of POV commands.
> 

In most cases, the "practical max" does not make any sense (for example
fade_power, fade_distance, rgb(ft)).  Furthermore sometimes even negative values
make sense.  

For things like rotate/translate you should simply write "any value", for scale
0.0 is not allowed.

Anyway it could probably be a quite useful collection for the beginner.  

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


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From: Chuck Roberts
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:14:07
Message: <39C22E9E.5D30624D@alleganisd.org>
Thank you for your valuable comments.

Warp wrote:
> 
> Chuck Roberts <cro### [at] alleganisdorg> wrote:
> : <li>float: a decimal number
> 
>   It can also be: A float in the format: <base>e<exponent>, eg. -1.23e-10,
> a float identifier and the return value of a float function.

What is the float function and how is it used? An example would
be nice. 

> 
> : <li>vector: in the format: <a, b, c> or just a. Each number is a
> : float. If the format is "a", that is equivalent to <a, a,
> : a>.
> 
>   A vector can also be two, four and five-dimensional.

Under what conditions or POV statements would it be 4 or 5
dimensional? (Besides a color with the f and/or t parameters.)

> 
> : <tr><td>rgbtf<td>vector<td>0.0<td>1.0
> 
>   A color component can be larger than 1 and smaller than 0 and still have
> a desired and considerable effect in the scene.

Thanks. I didn't know that. 

> 
> : <tr><td>turbulence<td>vector<td>0.0<td>1.0
> 
>   There's no reason why one should limit the turbulence value to 0-1. Negative
> values and values larger than 1 can have a desired effect.

Thanks again. 

> 
> : <tr><td>ambient<td>float<td>0.0<td>1.0
> 
>   Setting the ambient and similar values larger than 1 can have a considerable
> effect with things like fog, media, radiosity, etc.
> 
>   Some values (such as 100.0) seem quite arbitrarily chosen. Where did you
> get those values?

They were arbitrary. I can remove the upper limits on some of
those commands.


-- 
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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From: Warp
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:23:19
Message: <39c230d5@news.povray.org>
Chuck Roberts <cro### [at] alleganisdorg> wrote:
: What is the float function and how is it used? An example would
: be nice. 

  It's not THE float function, it's A float function.

  It's any function returning a float value. For example: sin(), cos(),
strlen(), etc.

: Under what conditions or POV statements would it be 4 or 5
: dimensional? (Besides a color with the f and/or t parameters.)

  With the colors at least. I don't remember if there's any other place where
the 4th and 5th components have a meaning.

:>   A color component can be larger than 1 and smaller than 0 and still have
:> a desired and considerable effect in the scene.

: Thanks. I didn't know that. 

  For example, if you set the color of a light source larger than 1, it will
be brighter. It may also have some effect on things like fog, media, etc.

-- 
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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From: Tom Melly
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:24:14
Message: <39c2310e@news.povray.org>
"Chuck Roberts" <cro### [at] alleganisdorg> wrote in message
news:39C22E9E.5D30624D@alleganisd.org...

<snip>

It might, in some cases, be worth distinguishing between usable values (for
example colour components greater than 1 or less than 0) and "normal" values
(0-1 in the case of colour comps.).

A new user being told that the range for a colour component is - infinity to
+ infinity is being somewhat led astray.


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From: Chuck Roberts
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:28:38
Message: <39C23206.31727B14@alleganisd.org>
You sound like you really know POV. I would be glad if you could
test my material editor for Win 9x when the next beta comes out
(Beta 4). It's at http://www.sourceforge.net/projects/ute/


Chuck


-- 
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

From: Christoph Hormann
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:32:01
Message: <39C232E1.638F0786@schunter.etc.tu-bs.de>
Warp wrote:
> 
>   With the colors at least. I don't remember if there's any other place where
> the 4th and 5th components have a meaning.
> 

julia_fractal and function parameters in megapov for example.

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


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From: Josh English
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:41:48
Message: <39C23552.373E4085@spiritone.com>
Warp wrote:

> Chuck Roberts <cro### [at] alleganisdorg> wrote:
> : <li>color: a color in one of the following formats:
> : "rgbft<a,b,c,d,e>"; "color Red"; "NamedColor".
>
>   A color can also be "rgb <a,b,c>", "rgbf <a,b,c,d>" or "rgbt <a,b,c,d>".
>
>   You should use < and >

Actually you should use < and > because not all the browsers understand
the names, but they all understand the code. (OK, IE and NS understand them, but
there are lots of other browsers out there.)

--
Josh English -- Lexiphanic Lethomaniac
eng### [at] spiritonecom
The POV-Ray Cyclopedia http://www.spiritone.com/~english/cyclopedia/


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From: Warp
Subject: Re: Pov reference, minimums and maximums for statements
Date: 15 Sep 2000 10:46:49
Message: <39c23658@news.povray.org>
Josh English <eng### [at] spiritonecom> wrote:
: Actually you should use < and > because not all the browsers understand
: the names, but they all understand the code.

  Aren't < and > part of the HTML standard? Why should we restrict
ourselves to some browsers which do not support the standard?
  As long as we make strictly standardized HTML, there's no problem. If a
browser doesn't support the standard, it's the headache of the browser,
not the maker of the page.
  And does the HTML standard say that < means '<' (the browser might
not be using the unicode charset)?

-- 
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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