Thanks for the positive response
@Martin: I had been fiddling around with WM and GeoControl now and then, and believe me, I feel much more comfortable with procedural heightfields than with the terragen's own powerfractals.
Except for the Alpine fractal shader, of course.
The good point of our most favourite rendering software is, that functions do work on heightfields, too ,-)
Now I have to continue with my Strata-Stuff ;-)
Volker