Firstly, my experiance comes from having designed and developed
software since 1978, I wrote my first (of many) parser/compiler at
age 17, I have written my own Raytracer as a project more than
15 years ago, can program in more languages and several processors
assembly code than I can shake a stick at. I have A level (pre-university
level)
qualifications in Maths, Further maths and passed the "Special Mathematics
Paper",
I have a quality degree in Computer Science and currently own my own
sucessful software house with 20 staff!    So - I know
what is difficult and what is  not.  Anyone writing a parser that cannot
cope with a bit of whitespace (the difference between 1cm and 1 cm)
should not be writing parsers.

Secondly, you are clearly either too arrogant or too stupid not to read what
I am saying.   I am not talking about portability of complete scene files
but
portabillity of the objects defined within different files from different
people.
I clearly agree with your simple example - my maths skills do extend that
far,
but you have clearly or deliberately missed the point - which is that I
would
like to cut a 1 object from a room scene you have created and "drop" it
into mine along with several others from within other scene files -  without
modification and without worrying about what your units of measure are
compared to mine.

Lastly ... you are being deliberately contentious and a complete prat and
just
looking to score some childish points as illustrated by your "This is
exactly my
opportunity." statement.

"ABX" <abx### [at] abxartpl> wrote in message
news:gq1nkvsldnbj4ui2he626l1vto6t7qfb3k@4ax.com...
> On Tue, 26 Aug 2003 17:06:21 +0100, "Alan Smith"
<ala### [at] aurora-ukcom>
> wrote:
> > As I said in my original posting, I would not want to force people to
> > have to use units on dimensions - it would be optional.
> > Quote - "This would surely be a simple modification to the parser and
> > would still leave the ability for people to work in a 'unit-less'
fashion if
> > they like?"
>
> From what experience "surely" in that quote come? This is exactly my
> opportunity. There is probably much work and the only benefit is that you
> don't have to type "*" because "cm" still have to be typed. But some
people
> will complain that they do not want "1cm" - they want "1 cm" or "1 CM" or
> "1centimeter". Moreover more possibilities, and making this unit optional
> makes parser only more complicated internally and increases parsing time.
>
> > You said there is no difference between various units.inc - I beg to
differ.
>
> Then you do not understand that text is translated into floats during
_final_
> parsing, not during posting scene or object via mailer. Simple, imagine
you
> have units.inc:
>
>   #declare cm=0.75;
>   #declare m=100*cm;
>   #declare km=1000*m;
>
> and a scene:
>
>   #version 3.5;
>   global_settings{assumed_gamma 1.0}
>   camera{
>     up 1*cm
>     right (image_width/image_height)*cm
>     direction z*1*cm
>     location -10*z*cm
>     look_at 0
>   }
>   light_source{90*m rgb 1}
>   sphere{ 0 1*km pigment{agate scale .5*km}}
>
> render it to image1.png. Now send it to your friend and ask to write own
> units.inc. The only requirement is that it has to define cm, m, km in
correct
> _relation_. Now ask him for rendering to image2.png. Then compare result.
Note
> he don't have to cm as base. He can for example made his units.inc as:
>
>   #declare m=12*76.13/143;
>   #declare cm=.1*m;
>   #declare km=1000*m;
>
> And now tell me. Is result different ? :-)
>
> ABX

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