Hi Michael,

you guys were right, I did it wrong the first time, but like I wrote, the "correct" (?) way also creates a mesh that seems to need a lot of additional work with manual clipping (not in this simple example, but in the production object).

Pilou, thanks, but your version creates a mesh with tons of control points and is very hard to deal with in the further process - and also not what I need in this specific case.

As for the endless mantra of "obj does not contain crease information": There are many ways around that limitation.
Either one can use "sharp edges" like pafurijaz wrote, use a different file format or have an editor on import where the user can add the weights manually.
But what I get from this discussion is a basic non-understanding of SubD and it's benefits when fully implemented, or at least a very limited interest in it.
We had that same discussion several years ago and got to the same point.

That is fine with me.

It's also somehow funny, since I heard the same from Rhino (and other CAD-) people for ages while they fumble around with crazy complicated workflows to create simple organic shapes with NURBS and now in Version 7 they rave about how SubD is a major breakthrough and "changes the way you work".
Yes, indeed...
The CAD world is just about 10-20 years late as usual...
Maybe one day MoI will do the same as Rhino does now, implement SubD as a native object format.

I personally am the other way around, I find NURBS a kludge that I only use when I have to. They have some specific technical benefits, but also massive drawbacks for organic design.
But that's a whole other can of worms...

As you were,

Tom