On Wed, 28 Nov 2001 14:26:08 +0000, s1631001 <s16### [at] namtarqubacuk> wrote:
> W?odzimierz ABX Skiba <abx### [at] babilonorg> wrote:
> > Do you know #include and #declare directive?
> I know I could just #declare a value for the golden ratio, (as I often
> do), but then we could do that for pi as well surely; we don't really
> _need_ them built-in, it's just handy.

Perhaps it is some kind of backward compatibility ?

> Mark Wagner <mar### [at] gtenet> wrote:
> > #fkill("c:\windows\win.com")
> Excellent point; I had considered that and, as Warp says, we would need
> restrictions on #fkill. Perhaps it could only kill files created by
> POV-Ray?

Why POV should introduce another level of privilages if it is rule of system
administrator ? AFAIK POV 3.5 inherits privilages from system.

> W?odzimierz ABX Skiba <abx### [at] babilonorg> wrote:
> > Are you thinking about matrices with transformations ?
> No, general matrices of arbitrary size. I guess my #macros will do the
> job (when finished), but I'd like to see built-in support.

So, the answer is IMO "POV-Ray is not mathematical tool but reytracer". POV
supports data structures nad programing tools to extend usage but base rule is
to trace objects.

> Now for the really contraversial one...
> I came up with the idea for the polygonal preview after a particulary
> long trace on my laptop (known as "The Breezeblock") which took several
> minutes for a test render (and this a fairly simple scene).
> isosurface{
>  $ISOSURFACE_STUFF$
>  approx_object{
>    union{
>      cylinder{ -2*x, 2*x, 1 }
>      cylinder{ -2*y, 2*y, 1 }
>      cylinder{ -2*z, 2*z, 1 }
>    }
>  }
> }

But you can still do that. Look below.

#declare Preview=yes; // or no
#if(Preview)
  isosurface{$ISOSURFACE_STUFF$}
#else
    union{
      cylinder{ -2*x, 2*x, 1 }
      cylinder{ -2*y, 2*y, 1 }
      cylinder{ -2*z, 2*z, 1 }
    }
#end

and this way is much more better
becouse you can mix previews with real appearances.

> Here's some more ideas for you to argue over...
>
> 5> animation variables "current_frame", "initial_frame", "total_frames"
> I am SO tired of having to redo an animation render because I #declared
> the wrong value for final_frame (usually because I test-render at a
> lower framecount)

you can find it in POV 3.5

> 6> The ability to tell POV-Ray when we only want an include file to be
> parsed once, instead of having to use special handling systems (check
> the very top and bottom of any standard include for example).

There is everything ok with 'special handling systems'. But you can read about
'project' idea sended by me in another thread.

ABX
--
#declare _=function(a,b,x){((a^2)+(b^2))^.5-x}#default {pigment{color rgb 1}}
union{plane{y,-3}plane{-x,-3}finish{reflection 1 ambient 0}}isosurface{ //ABX
function{_(x-2,y,1)|_((x+y)*.7,z,.1)|_((x+y+2)*.7,z,.1)|_(x/2+y*.8+1.5,z,.1)}
contained_by{box{<0,-3,-.1>,<3,0,.1>}}translate z*15finish{ambient 1}}//POV35

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Skiba <abx### [at] babilonorg>  wrote:

> Why POV should introduce another level of privilages if it is rule of system
> administrator ? AFAIK POV 3.5 inherits privilages from system.

Hmm, maybe because not every POV user is running Windows NT/2K/XP or a Unix
that is professionally administered by someone full-time?
Most people don't even know how to turn on/off java, let alone do they know
how to properly configure file/directory privileges in their system.  And
there are still many who run Windows 95/98/ME, which don't have any kind of
file/directory privileges.

    Thorsten

____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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On Wed, 28 Nov 2001 18:48:16 -0500, "Anders K." <and### [at] f2scom>
wrote:

>What definition? I'm not saying you're wrong or anything, just that I've
>seen it both ways.

Take a segment AB and a point C on AB. There is only one case in which
the ratio AC:BC equals BC:AB and this ratio is the golden ratio. If AB
is of unit length, then AC = 0.5*(sqrt(5)-1) and BC = 0.5*)sqrt(5)+1).


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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> What definition? I'm not saying you're wrong or anything, just that I've
> seen it both ways.

Just to give you an examples -- the golden ratio is defined as (sqrt(5) +
1)/2 in almost every site in Google's golden ratio category:

<http://directory.google.com/Top/Science/Math/Recreations/Specific_Numbers/p
hi/>
I say "almost" because one site was unclear about which of (sqrt(5) + 1)/2
or (sqrt(5) - 1)/2 it was calling the golden ratio, and two gave me 404s,
but every other one said it was (sqrt(5) + 1)/2.

Please don't misunderstand me -- I am not saying that one value is better
than the other one. You can decide for yourself which value you think is
right. I'm just saying that the golden ratio has been defined both ways, and
so including one of them as a builtin constant in POV-Ray would not be a
good idea.

Anders

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>
<http://directory.google.com/Top/Science/Math/Recreations/Specific_Numbers/p
> hi/>

Argh! Does anyone know of a way to keep Outlook Express from wrapping URLs?
:-)

Anders

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Peter Popov wrote:
> Take a segment AB and a point C on AB. There is only one case in which
> the ratio AC:BC equals BC:AB and this ratio is the golden ratio. If AB
> is of unit length, then AC = 0.5*(sqrt(5)-1) and BC = 0.5*)sqrt(5)+1).

A             B   A      C      B
._____________.   .______x______.  <- AC==AB, which leads to AB&&BC==0.5
if AB==1.  So make that 2 cases ;)

-- 
Tim Cook
http://empyrean.scifi-fantasy.com

-----BEGIN GEEK CODE BLOCK-----
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N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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"Thorsten Froehlich" <tho### [at] trfde> wrote in message
news:3c0652f1@news.povray.org...
>And
> there are still many who run Windows 95/98/ME, which don't have any kind
of
> file/directory privileges.

Thank goodness 3.5 does :)

...Chambers

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On Thu, 29 Nov 2001 22:49:25 -0500, "Timothy R. Cook"
<tim### [at] scifi-fantasycom> wrote:

>So make that 2 cases ;)

The Greek thought that a rectangle whose sides are in the golden ratio
is most pleasing to the eye. Now, whether you make them 1:1.618 or
0.618:1 is irrelevant, as this is the same ratio. So there - there
really is *one* ratio.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg

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Since t is a *ratio*, it doesn't matter whether you use t or 1/t,
they'll give the sme results. Interestingly for t = (1+sqrt(5))/2, 
(t-1) = (1/t)

Peter Popov wrote:
> 
> On Thu, 29 Nov 2001 22:49:25 -0500, "Timothy R. Cook"
> <tim### [at] scifi-fantasycom> wrote:
> 
> >So make that 2 cases ;)
> 
> The Greek thought that a rectangle whose sides are in the golden ratio
> is most pleasing to the eye. Now, whether you make them 1:1.618 or
> 0.618:1 is irrelevant, as this is the same ratio. So there - there
> really is *one* ratio.
> 
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] vipbg
> TAG      e-mail : pet### [at] tagpovrayorg

-- 
signature{
  "Grey Knight"
  contact{ email "gre### [at] yahoocom" }
  site_of_week{ url "http://mathworld.wolfram.com" }
}

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Peter Popov wrote:
> The Greek thought that a rectangle whose sides are in the golden ratio
> is most pleasing to the eye. Now, whether you make them 1:1.618 or
> 0.618:1 is irrelevant, as this is the same ratio. So there - there
> really is *one* ratio.

As I said, I wasn't paying attention to what I was writing; thought
it said AB:BC = BC:AB.
-- 
Tim Cook
http://empyrean.scifi-fantasy.com

-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GFA dpu- s: a?-- C++(++++) U P? L E--- W++(+++)>$
N++ o? K- w(+) O? M-(--) V? PS+(+++) PE(--) Y(--)
PGP-(--) t* 5++>+++++ X+ R* tv+ b++(+++) DI
D++(---) G(++) e*>++ h+ !r--- !y--
------END GEEK CODE BLOCK------

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