"Kenneth" <kdw### [at] earthlinknet> wrote:
> I should qualify that: It worked beautifully, because I applied the slope
> map pattern over a previous texture. But used by itself (as the only
> texture), strange things happen, as I've since discovered.
>
> Can someone p*l*e*a*s*e explain why the following two examples show
> different slope pattern results? I have some theories, but they're all pure
> wacky guesswork.
>
> The first example shows the way the slope pattern worked succesfully for me
> (and it makes sense) :  The pattern is applied over a previous (white)
> texture, and its red color fades to transparency as it reaches the opposite
> side of the sphere.  Just what I wanted! But the second example--using the
> slope pattern alone--shows the red color appearing on BOTH sides of the
> sphere. Why so?
>

That is a bit of a conundrum.  What happens is that as the rays hit the
sphere, they evaluate the slope and apply the pigment.  Now in areas where
the sphere is transparent or partially transparent, the rays continue
through and hit the back of the sphere from the *inside* and evaluate the
slope of the normal of this surface which gives opposite results of the
front surface. So the extra pigment you see is actually on the inside of
the opposite surface of the sphere as seen through the transparent texture
on the front surface.
Now how to get around this may be a tad more complex, I'll have to think
about that.

-tgq

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