Hi Micha,

> The initial uv layout should be quite good to create a mesh of quads only or?

No, not good enough to match the parameters - whenever you see adaptive subdivision it means that the initial quad polygon in that area did not match the tolerance and needed to be subdivided.

That's the _only_ reason why things get adaptive subdivision on them...

The part that makes the initial grid has some limits on it to try and avoid creating too huge of a uniform mesh. You can imagine for instance that trying to do a uniform mesh on an object like the one shown here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=2379.3 would make for a huge number of polygons.

Also if the surface has varying curvature throughout it like the one you show there, it is not likely to get a dense enough initial grid to avoid all adaptive subdivision, the part that does the initial gridding is more focused on getting a "perfect" initial grid on uniformly curved objects like a cylinder or sphere. It is generally assumed that something with varying curvature may need adaptive subdivision in areas to put more polygons in areas of tighter curvature...

One thing I've been thinking of is possibly adding a setting that would let you turn off adaptive subdivision entirely, that would probably be useful for things like this.

- Michael