I'm not sure, but the slope pattern may not be working correctly(?).
I went back through the postings in several newsgroups, but didn't see
anything about it.

Using slope {0,-1,0} and without choosing Lo_slope and Hi_slope values, the
pattern does what is expected....covering the object "fully" with a
color_map or texture from top to bottom (that is, assigning the color_map
to the full 0-to-1 "slope"...all the object's normals.)

But sticking in Lo_slope and Hi_slope values ...like 0, .5
respectively...doesn't *seem* to do what the docs say:

"By specifying Lo_slope and Hi_slope you get more control:
  slope { <Direction>, Lo_slope, Hi_slope }
Lo_slope and Hi_slope specifies which range of slopes are used, so you can
control which slope values return which pattern values. Lo_slope is the
slope value that returns 0.0 and Hi_slope is the slope value that returns
1.0."

The way I read it, if I choose Lo_slope and Hi_slope to be 0 and .5, then
the function should completely ignore any object normals outside that range
and should map the full color_map only to the specified normals, nowhere
else. But the color map repeats at slope .5 and continues down to slope
1.0. ...in other words, it's re-applied to the object's
normals that are outside the range.
 If I make Hi_slope something like .2, then the visual result is
exactly the same as if I had used the frequency keyword on a typical
pattern: the color map repeats five times.

Is it meant to work this way? It would be much more useful (to me) if the
colors were mapped ONLY to the object's specified normals range. For
example, for "partially" texturing an object that already has another,
earlier texture applied to it. Using <altitude> along with Lo-alt and Hi_alt
is a cumbersome way to go about that, with a somewhat different result (and
the color_map still repeats.)

Ken Walker

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