On Fri, 5 Mar 1999 17:43:33 +0100, Daniele Varrazzo 
	<pir### [at] officineitnospam> wrote:
>>                  /
>>_ _ _ _ _ _ _ _ _/_ _ _
>>    /\           \
>>   /A \         B \
>>
>>The dotted horizontal line is your ray.  At A, it hits an edge that should
>>not be counted.  At B, it hits an edge that should be counted.  Each is
>>shared between exactly two faces.
>
>
>What happens if we count even A as one intersection? Could there be errors?
>Would they be very noticeable?

Yes, there will be errors.  A is either zero intersections or two intersections.
If you count it as one intersection, it will invert the insideness for every
point to the left of A.  In practice, this shows up as a row of random-looking
pixels in your scene.  The text and prism objects in the official POV-Ray used 
to have this problem, too; I think the prism objects still do.

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