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.

    It was one of those fantasy POV universes not just a country.

    As to the general issue, consider writing ascii to the screen in the old
days or even today if anyone is still into it. 0,0 is top left corner, x
increases to the right, y down. It really sucked. With me so far?

    Now the right hand rule to find increasing Z it to "wrap" x into y and
your thumb points at z. With the above system z increases into the screen.
Voila!!! POV-ray. Rather the first incarnation when it was called something
else entirely.

    The next step is to set an arbitrary origin with respect to where the
camera looks. Once you do that 0,0 is no longer in the upper left corner.
This presents a minor problem in conceptualization. X still increases to the
right but y is down that is very annoying to most everyone with math
experience, even those who avoided math as much as possible. But since it is
arbitrary make it up just like all the early computers users thought it
should have been, with 0,0 in the lower left.

    Now where are we? We have corrected the major annoyance of the first
computer screens. However we have that annoying right hand rule making z
increasing coming out of the screen as opposed to the original which was the
opposite and what it is now.

    But which direction z increases is arbitrary so lets make it intuitive.
How far away is an object? The farther away the larger the number, intuitive
with the image.

    Second to lastly, someone comes back and says that is a left-handed
coordinate system. Not that it matters once you simply memorize the
directions of the ups.

    Lastly the docs get all technical on us and start off with saying it is
a left-handed and start confusing people "right" and "left" to so speak.

    Finally there is a solution! Rats become commonplace. Most people are
right handed. Only their left hands are free to figure out which way is up.

    And we have so many POV-ray users who consult their left hands before
getting out of bed so they don't fall to the ceiling. They are among the few
who have to think before they know which way is up.

> I'd like a plot in this little burg of yours, but I'm afraid that it'll
> never work since I'll be using Moray.

    Real men don't use modelers. ;)

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