"Phil Cook" <phi### [at] deckingdealscouk> wrote in message
news:opru931zpaeybzwd@news.povray.org...
>
> Well looks like I can answer my own question, after a bit of
> experimentation I think the following explains the scaling situation,

<snip>

> which makes sense just multiple the vectors by the scale, it's a shame that
> the help file uses a 0 sphere as it's example, as this won't show any
> translation (0*any number =0).
>
> This is probably well known and understood by POV-Ray writers more
> competent than myself, but it confused the heck out of me at first.
>

I think everyone runs into this one at some moment - it's very tied in to the
(wrong) assumption that every pov-primitive has a defined center (which could
therefore stay in one place even when the object is scaled).

Without a defined center, how could any object stay in one place when you
changed its size?

The bottom line is that it's a good idea to locate a known point of your object
at <0,0,0> prior to scaling.

Extending this to all the transforms, except in special cases*, I tend to follow
what I call the 'open the door' rule - grasp the handle (scale), turn (rotate),
open (translate).

* for example, for the markers on a clock-face, I would tend to translate first,
then rotate.

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