Slime wrote in message <3bd9faea$1@news.povray.org>...
>Well, it makes sense that it may happen when the rays have extremely low
>slopes (that is, they go over 1 unit in the X direction for every 100000 or
>so units in the Z direction), but why does it happen with an orthographic
>camera? At only a distance of about 1000 units? Surely POV can handle more
>than four decimals.


The problem is that a torus is a fourth-order polynomial.  So, in order to
get four decimal places of accuracy in a ray-torus intersection, POV-Ray
needs a whole lot more decimal places of accuracy in the intersection code.
I'm not sure about the exact math POV uses, but I would guess that for four
decimal places of accuracy, you'd need variables that can store 16 decimal
places.

--
Mark

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