Brook Monroe wrote:
> 
> The Y axis is UP?  What country did YOU study geometry in? <G> This is
> going to ruddy well make things difficult to produce in Moray, you know.

Yeah, it is....x is left-right, z is forward-back (into-outof), and y is
up-down....even maths geometry bears this out, on a 2d graph, x is
horizontal, y is vertical...if you add a third axis it Must be
forward/backwards.
-- 
** The only good politician is a dead politician.
** Email me: bay### [at] coastlinkcomau
** Believe 1% of what you see or hear.
** Always read between the lines.

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Actually, traditional cartesian coordinates in 3-space have a vertical z
axis with x going in and out and y left to right.

Ken

BearFace wrote in message <348### [at] coastlinkcomau>...
>Brook Monroe wrote:
>>
>> The Y axis is UP?  What country did YOU study geometry in? <G> This is
>> going to ruddy well make things difficult to produce in Moray, you know.
>
>Yeah, it is....x is left-right, z is forward-back (into-outof), and y is
>up-down....even maths geometry bears this out, on a 2d graph, x is
>horizontal, y is vertical...if you add a third axis it Must be
>forward/backwards.
>--
>** The only good politician is a dead politician.
>** Email me: bay### [at] coastlinkcomau
>** Believe 1% of what you see or hear.
>** Always read between the lines.

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BearFace wrote:

> Brook Monroe wrote:
> >
> > The Y axis is UP?  What country did YOU study geometry in? <G> This is
> > going to ruddy well make things difficult to produce in Moray, you know.
>
> Yeah, it is....x is left-right, z is forward-back (into-outof), and y is
> up-down....even maths geometry bears this out, on a 2d graph, x is
> horizontal, y is vertical...if you add a third axis it Must be
> forward/backwards.
> --
> ** The only good politician is a dead politician.
> ** Email me: bay### [at] coastlinkcomau
> ** Believe 1% of what you see or hear.
> ** Always read between the lines.

  I disagree.  The Cartesian plane is 2D, x/y, traditionally considered to be
a flat horizontal surface (read "Flatland"), and we (the 3D folks) inhabit the
domains spread out along the Z axis.  To look at it another way, X is
east-west, Y is north-south, and Z is in the atmosphere or underground.  Don't
get all hornswoggled because your algebra teacher drew graphs on the
blackboard.

jbm!

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On Tue, 09 Dec 1997 21:42:01 -0500, Brook Monroe
<rin### [at] worldnetattnet> wrote:

>The Y axis is UP?  What country did YOU study geometry in? <G> This is
>going to ruddy well make things difficult to produce in Moray, you know.
>

Well, you know, that was my first thought.  I'm a long time user and
strong supporter of MORAY.   And although Y=UP is a bit alien to me
now too, it shouldn't be a problem.  I intend to use MORAY (for
Windows) and just build everything so that Y is UP, even if MORAY
thinks Z is up.   I could be wrong --- I havn't tried it yet --- but
it should work.


-----------
George Hunt --- Raytracer Obsessivo
http://ourworld.compuserve.com/homepages/lightsword
102### [at] compuservecom
-----------

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Up until today I was doing my geometry wrong also, until I asked my math
teacher which was axis should be pointing.

It really shouldn't be that much trouble.  Just model it in Moray like you
always would, but keep it centered on <0,0,0>.  You can then fix it with a
couple rotate and translate commands.

Being an American, using the metric system (1 unit = 25 meters) will be alien
to me as well.  That is not so easily fixed.

Don't be suprised if my residence is scaled wrong. : )

~Kardal~

George Hunt wrote:

> On Tue, 09 Dec 1997 21:42:01 -0500, Brook Monroe
> <rin### [at] worldnetattnet> wrote:
>
> >The Y axis is UP?  What country did YOU study geometry in? <G> This is
> >going to ruddy well make things difficult to produce in Moray, you know.
> >
>
> Well, you know, that was my first thought.  I'm a long time user and
> strong supporter of MORAY.   And although Y=UP is a bit alien to me
> now too, it shouldn't be a problem.  I intend to use MORAY (for
> Windows) and just build everything so that Y is UP, even if MORAY
> thinks Z is up.   I could be wrong --- I havn't tried it yet --- but
> it should work.
>
> -----------
> George Hunt --- Raytracer Obsessivo
> http://ourworld.compuserve.com/homepages/lightsword
> 102### [at] compuservecom
> -----------

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Just work in feet or something and then add a final scale statement to
change it to 1 unit=25 meters.  If you work with 1 unit = 1 foot, then when
you're done, scale your scene by 82.020997 and that should give you 1 unit =
25 meters.

Ken


Kardal wrote in message <348F06AD.E01D8D9E@geocities.com>...
>
>Being an American, using the metric system (1 unit = 25 meters) will be
alien
>to me as well.  That is not so easily fixed.
>
>Don't be suprised if my residence is scaled wrong. : )
>
>~Kardal~
>
>George Hunt wrote:
>

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Hi Pals,

Sorry to say you are all besides the point.
POV-Ray handles very well both left and right handed systems, just check
your docs, in WinPov 3.01 check sections :
==> 4.1.1 Understanding POV-Ray's Coordinate System
and
==>7.4.4.5.2 Handedness

That being said, a choice as been made by the main contractor to build a
left handed world, not a single problem, the one who builds a right
handed system will simply have to scale his model to <1, 1, -1> then
rotate it appropriately so that it matches the right directions, then
translate to the plot - easy.

Hope this helps,
Al.


=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
=-=-=-=-= ANTI SPAM / ANTI ARROSAGE COMMERCIAL : 

To answer me, please take out both minus signs from my address.

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Alain CULOS wrote:

> Hi Pals,
>
> Sorry to say you are all besides the point.

Principles are never besides the point.

> POV-Ray handles very well both left and right handed systems, just check
> your docs, in WinPov 3.01 check sections :
> ==> 4.1.1 Understanding POV-Ray's Coordinate System
> and
> ==>7.4.4.5.2 Handedness
>

Whatever.

> That being said, a choice as been made by the main contractor to build a
> left handed world, not a single problem, the one who builds a right
> handed system will simply have to scale his model to <1, 1, -1> then
> rotate it appropriately so that it matches the right directions, then
> translate to the plot - easy.
>

Great, then I'll just send my scene files to you and you can do it.  It's
already going to be hard enough to create something at the microscopic scale
of 1 unit = 25m (= 82 ft), without having to re-do the scaling and rotation
at the end.

And I still say Z is altitude.

jbm!

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Create your scene with any orientation or scale you would like to.  Make one
unit equal to a mile if you want.  Just make sure you relate 1 unit to some
known measurement, and I'LL be glad to rerotate your scene and scale it to
match the specs.  The specifications should have no impact whatsoever on
your modeling.

Ken


Brook Monroe wrote in message <3490208C.C0FE5858@worldnet.att.net>...
>
>
>Alain CULOS wrote:
>
>> Hi Pals,
>>
>> Sorry to say you are all besides the point.
>
>Principles are never besides the point.
>
>> POV-Ray handles very well both left and right handed systems, just check
>> your docs, in WinPov 3.01 check sections :
>> ==> 4.1.1 Understanding POV-Ray's Coordinate System
>> and
>> ==>7.4.4.5.2 Handedness
>>
>
>Whatever.
>
>> That being said, a choice as been made by the main contractor to build a
>> left handed world, not a single problem, the one who builds a right
>> handed system will simply have to scale his model to <1, 1, -1> then
>> rotate it appropriately so that it matches the right directions, then
>> translate to the plot - easy.
>>
>
>Great, then I'll just send my scene files to you and you can do it.  It's
>already going to be hard enough to create something at the microscopic
scale
>of 1 unit = 25m (= 82 ft), without having to re-do the scaling and rotation
>at the end.
>
>And I still say Z is altitude.
>
>jbm!
>
>
>

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Ken was faster than me on that one, but the *EASY* way out is do your
scene as he says in whatever you like, for instance you want :
1ft=1unit
Z=up
Y=into the screen
X=right
this is a right handed coordinate system

Embed your whole construction into an object :

/*
  world in left handed coordinates, unit = 25 metres
  y = up
  x = right
  z = into the screen
*/
object
{
   /*
       your whole construction goes there,
       it is meant to be starting at <0, 0, 0>
       and extend as far as <738, 738, 164>
       unit in feet
  */
  rotate 90*x
  // that changes :
  // = up(z) to up(-y)
  // = right(x) is preserved
  // = into the screen(z) to into the screen(y)

  scale <1, 1, -1>/82
  // to bring your up(-y) to up(y) and
  // change the scale to 1unit=25metres

  translate to <0.5, -0.01, 0.5>
  // to put it into the first slot allocated,
  // change that translation for another slot
}

I personally find this sort of things easy, if you don't just let me
know exactly what you want and I'll tell you the transformations.

Cherio,
Al.

Brook Monroe wrote:

> Alain CULOS wrote:
>
> > Hi Pals,
> >
> > Sorry to say you are all besides the point.
>
> Principles are never besides the point.
>
> > POV-Ray handles very well both left and right handed systems, just check
> > your docs, in WinPov 3.01 check sections :
> > ==> 4.1.1 Understanding POV-Ray's Coordinate System
> > and
> > ==>7.4.4.5.2 Handedness
> >
>
> Whatever.
>
> > That being said, a choice as been made by the main contractor to build a
> > left handed world, not a single problem, the one who builds a right
> > handed system will simply have to scale his model to <1, 1, -1> then
> > rotate it appropriately so that it matches the right directions, then
> > translate to the plot - easy.
> >
>
> Great, then I'll just send my scene files to you and you can do it.  It's
> already going to be hard enough to create something at the microscopic scale
> of 1 unit = 25m (= 82 ft), without having to re-do the scaling and rotation
> at the end.
>
> And I still say Z is altitude.
>
> jbm!

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