Hi,

I'm designing a system to make a controlled landscape
with a height_field when I stumbled over this strange
behaviour.
I use the Gaussian formula ( exp((-x/sigma)^2) ) to generate
the crude mountain shape and add a fine structure with
'f_hetero_mf()' to get the real mountain view.
In the example (see povray.text.scene-files) I have
removed the fine structure and everything that don't
contribute to the problem.
The problem appears when I rotate the mountain.
The sigma values for the length and width of the mountain
in the X- and Z-direction (translated in the formula to Y)
have to be combined with cos(Rot) and sin(Rot) for the
rotation (see the #switch-section).
When I do that, things go wrong. You can see for yourself
if you change the 'Test-value' in the beginning of the file.
I have checked all the '()' over and over, but that is allwright.
Somehow a multiplication factor is added and I can't
figure out where it is coming from.

Anyone who sees what is going on??

Jaap Frank

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