> In all cases, there was no red with
> AA off but with AA method 1 and AA method 2, there was red on
> the left edge and on the bottom edge.

With AA off, the camera is still shifted by 1/2 pixel; you just don't see
any red since the camera rays still end up on the box.

> I then tried povray 3.1 (I was running v3.1 and v3.5 at
> the same time, rendering the same file, how cool is that?) and
> the effect did not happen!  No red!

That's because the AA threshold is playing tricks on you. Try +am2 or +a0.0
and you'll see that the problem is still there.

> Could it be a floating point error as a result of
> switching to a different c compiler?

No. I've looked at the 3.1 source, and the problem is a bug in the code. See
my earlier thread about this bug:
http://news.povray.org/3bccc696@news.povray.org

Anders

Post a reply to this message