ingo said:

>Digital archeology, the business of the future?

and then ken said:

>Are you looking for a converter to convert from POV-Ray to another
> file format? If so stop looking. There is none.

hmm... so maybe we're not talking digital archaeology here
but digital astronomy instead...  a big dark hole that sucks
in any format that comes near it, emitting nothing but the
mysterious and puzzling mind-rendering pov rays.   ;-)

miker

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"MR" <a### [at] bnet> wrote in message news:3bb87843$1@news.povray.org...
> ingo said:
>
> hmm... so maybe we're not talking digital archaeology here
> but digital astronomy instead...  a big dark hole that sucks
> in any format that comes near it, emitting nothing but the
> mysterious and puzzling mind-rendering pov rays.   ;-)
>

The problem, as I understand it, is that POV scene-files do not (generally) just
list a series of primitives with simple csg. Most pov files contain macros and
other constructs that would defeat any rational process of conversion.
Converting such a scene would essentially require rendering the scene and then
applying some form of tesselation to the scene-objects. Not really practicle.

Most modelling packages output meshes or similiar which are relatively trivial
to convert.

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Tom Melly wrote:
> The problem, as I understand it, is that POV scene-files do not
> (generally) just list a series of primitives with simple csg.
> Most pov files contain macros and other constructs that would
> defeat any rational process of conversion.

Macros?  This is something I myself am unfamiliar with, so.
Why can't you convert .pov file that just has primitives/csg
to another format?

...of course, why would you want to use anything other than
POV...;)

-- 
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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"Timothy R. Cook" wrote:
> 
> Macros?  This is something I myself am unfamiliar with, so.
> Why can't you convert .pov file that just has primitives/csg
> to another format?
> 
> ...of course, why would you want to use anything other than
> POV...;)
> 

See:

http://www.students.tut.fi/~warp/povVFAQ/filesVFAQ.html#povtootherformatsdifficulty

You could of course define a restricted subset of the POV language for
conversion, but such a converter would not be of much practical use.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

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"Timothy R. Cook" wrote:

> Why can't you convert .pov file that just has primitives/csg
> to another format?

Just to illustrate how difficult it would be let's look at just some
of the many ways to describe a simple sphere object. Each of these
will accomplish the exact same thing yet the syntax used will vary -

//traditional
sphere{<1,1,1>,1 pigment{rgb 1}}

// Another
sphere{x+y+z,1 pigment{rgb 1}}

//Yet another
#declare a=x*1;
#declare b=y*1;
#declare c=z*1;
#declare d=1;
#declare My_Sphere = sphere{a+b+c,d}
object{My_Sphere pigment{rgb 1}}

//and one last one
#declare My_Vector = <1,1,1>;
sphere{My_Vector,1 pigment{rgb 1}}


Each of the above examples are perfectly valid and illustrate the
various types of POV-Ray scene file coding in practice today. A
pov2xxx conversion program would have to be able to recognize
each of those varations and decide what to do with them. That is
just the beginning. Then, since POV-Ray objects are mathematical
representations, they would have to be tesselated into a triangle
based or similar system, that most other 3D file formats use. Do
you start to see some of the practical problems involved ?

-- 
Ken Tyler

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Ken wrote:
> Each of the above examples are perfectly valid and illustrate the
> various types of POV-Ray scene file coding in practice today. A
> pov2xxx conversion program would have to be able to recognize
> each of those varations and decide what to do with them. That is
> just the beginning. Then, since POV-Ray objects are mathematical
> representations, they would have to be tesselated into a triangle
> based or similar system, that most other 3D file formats use. Do
> you start to see some of the practical problems involved ?

Hmm.  Yeah, that is a challenging thing.  But...pov can parse
each of the things, and there are already-existing tesselations
for spheres-to-triangles (it's what those other, wimpier 3d
modellers like 3d studio use).  So it's not impossible, nor
terribly unfeasable...pov IS open source, ain't it?  So the
parsing code is already available.

...but then, you're not allowed to use pieces of POV in
other software.  Ok, so much for that idea.

-- 
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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"Timothy R. Cook" wrote:

> Hmm.  Yeah, that is a challenging thing.

Quite.

>  But...pov can parse
> each of the things, and there are already-existing tesselations
> for spheres-to-triangles (it's what those other, wimpier 3d
> modellers like 3d studio use).  So it's not impossible, nor
> terribly unfeasable...pov IS open source, ain't it?  So the
> parsing code is already available.

Ah, but POV-Ray is not "open source". The source is provided for
educational purposes and so that you can make modifications to
it for your own edification and enjoyment. Redistribution has
strict rules that must be adhered to which limits for what
you suggest here.

> ...but then, you're not allowed to use pieces of POV in
> other software.  Ok, so much for that idea.

Bingo! If you could strip out the front end language parser
then you will have won a major part of the battle. In fact
nothing is preventing you from doing that for your own private
use. However you would not be able to redistribute it so the
time spent might not be worth the effort from a community
point of view.

-- 
Ken Tyler

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