Keeping subD-vertex 90 degree in smooth display

Hi there! Probably amateur question, but I just can’t figure it out.
Basically I am trying to achieve this


from the forum topic: Having trouble with creases not working as expected in SubD - #2 by martinsiegrist but still haven’t got a clue why on earth is it not working in my case.

I have 2 subD models, which I would like to 3D print and connect phisically, Therefore the joining surfaces should be perfect. While I managed to keep a subD-vertex perfectly 90 degree on the first model (M1) in smooth display, I just cannot do it on the second model (M2). I was using the _SubDCrease command to have creased, square surfaces on (M1), or at least that’s how I recall it. I am clearly missing something here and I need some help please.


Thank you!

It would help if you could share the rhino file.

Yes Sir! I attached the rhino file for further details. Thank you!
Model 02 - forum.3dm (4.6 MB)

Do you want to create a bridge?

And crease these edges?

Nope. I would like the keep the two separate models, but to have a square surface on both of them of the same size, even when I am in smooth display. The one on M1 is perfect, but I cannot find a way to make it on M2 as well - even though it is perfect in flat display but it transforms into a circle in smooth display.

Like so?

That is EXACTLY what I was trying to do :pray:
Would you share the magic please?

I creased these 8 edges

That is the most wonderful thing I saw in the past 24 hours. Thank you very much for your help, it works like a charm!