Alain <ele### [at] netscapenet> wrote:
> >
> For a "default" camera where the right vector have been changed, the
> horizontal field of view don't change with the right vector. The
> direction vector can be used to change the angle of the field of view.
> In early versions, before the angle keyword was introduced, it was
> the only way to change the field of view.
>
> The up and right vectors determine the aspect ratio. They work by changing the
> vertical field of view.


Okay, yes, they change the aspect ratio, and they can mess it up by giving you a
scenario where circles are not circular if you're not using 4x3 pixel ratio.

So, I'm doing:

 right x*1.33
 up image_height/image_width*y*1.33

Now, regardless of what I do with the +H and +W switches, circles will be
circular.   The problem is I may want to change the angle at some time. With
the above code, I *can* change the horizontal field of view with:


 right x*the_right
 up image_height/image_width*y*the_right

where I plug in a number for "the_right".   I guess I'm looking for a good
camera definition, a graphical image of what all the vectors mean in the
default camera.  The one at

http://www.povray.org/documentation/view/3.6.1/246/

is completely lacking for the definition of a default camera.  Is 1.33 the x
distance seen at the plane <0,0,1>???

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