Hi Pixelhouse,

Here's a bit of info since you mentioned "Maybe its just a dream to export my landscapes to an step-file :)"

High frequency detail as found in nature is poorly represented by nurbs. In fact, if you convert a polygon model or raster data to nurbs you are losing information if your goal is to represent the information as faithfully as possible. So I would ask you to evaluate your need to have a nurbs surface.

It is a common requirement to have nurbs model for milling steel to make an injection mold, particularly for best surface finish. Therefore, it seems to be a misconception that the nurbs model is the best format for everything, while for some applications it may not be.

Many CADCAM programs can accept facetted (triangulated) representations such as STL, so there is no need for a nurbs surface if the end use will be the machined model and/or you are not making tooling for injection molds.