"Tony[B]" wrote:
> Can someone please explain this to me in simpler
> terms than those used in the MegaPOV docs? I've
> been struggling to get this thing to work on
> heightfields higher than 1 unit (in my case a
> heightfield 3.28 units high, which will be
> changed later). Specifically the one with syntax:
> slope, <x,y,z>,<x,y,z>,<u,v>,<u,v>. An example is
> greatly appreciated. TIA

slope, <x,y,z>,<x,y,z>,<u,v>,<u,v>
          A       B      C     D

You have four vectors. Let's call them vector A, B, C and D. A and B are 3D
vectors. C and D look like 2D vectors in their syntax, but in fact they have
nothing to do with vectors.

A is a 3D vector controlling the which direction the slope pattern is based
on. As I'm sure you understand that one, I won't go into details.

C is used to give you better control over A. If you're using a heightfield
and A is set to be y you are not having any surfaces that are anti-parallel
to A (-y). Actually, even the most steep surfaces of the HF would be
perpendicular to the slope vector at most. That means the pattern only will
return values from 0.5 (perpendicular) to 1.0 (parallel). The part of your
color_map that uses values from 0.0 to 0.5 is sort of wasted, since it's
never used.

You can use C to specify that only a certain range of slopes are used. The u
part in C sets the lo-slope and the v part sets the hi-slope. For example,
if you set C to be <0.5,1.0> it means that the pattern value goes from 0
when the slope is perpendicular to A, to 1 when the slope is parallel to A.
That means that your entire color_map is used, even though only a certain
range of slopes are used.

Let me know if it's clear so far!

To be continued...

In the next message I'll try to explain how to use the slope pattern with
heightfields higher than 1 unit! But maybe someone will beat me to it...

Rune
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