Am 28.02.2013 04:22, schrieb Kenneth:
> Here's something else I thought to mention (but sorry for the delay) concerning
> the camera statements in the various demo scenes.
I had this feeling too!

> ...    In the docs about
> "Handedness" it says:
>
> "To use a right-handed coordinate system...Your thumb still points up in the
> +y-direction...."
'right-handed' or 'left-handed' does not necessarily mean y=up or z=up
  (or may be also x = up ! - Why not ?? ).
It only means, that to detect the used sense of rotation, we can help
us by looking at our right or left hand!
(This has specially repercussions also on the way, how the rotation and
  the cross product works!)

The docs are here a bit incomplete!

> Of course, to fix this situation would mean re-coding some of the scenes
> themselves, if they are still to render as originally intended  (a lot of work!)
> But an easier solution might be a simple statement, something like "This scene
> uses a non-standard camera set-up. (See CAMERA in the included documentation for
> details.) If you are new to POV-Ray, you might want to try a different demo
> scene."
I'll try to integrate something like this in as many files as possible.
Re-coding all is not possible and also not the best way!
It's also a good thing, that the bundle of demo scene files shows
the variety of the ways, how to use the 'camera'.

  'right-handed' is just a convention, often used math teachers,
to make it easier to talk about how axes are orientated and how
angles turn. (later they tell us, that electrons are left-handed :-))
POV-Ray is able to do also very inconventional things.
That's very good!

Friedrich

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