In article <3fc50a5c@news.povray.org>, Warp <war### [at] tagpovrayorg> 
wrote:

> Carl Hoff <hof### [at] wtnet> wrote:
> > I think what I'm trying to do would keep all strait lines as strait lines
> > after the transformation.  Although lines that were parallel before the
> > transformation might not be after.
> 
>   Nope. If parallel lines do not keep parallel after the transformation,
> then there exist lines which do not keep straight after the transformation.

Actually, they can remain straight with a transformation that makes 
parallel lines non-parallel...scale two axii by the value of the third, 
flipping everything around at the origin. It wouldn't be an affine 
transform though, it would not be invertible (a singularity at a plane 
going through the origin where all points transform to < 0, 0, 0>), and 
it can not be expressed as a matrix.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/

Post a reply to this message