Sub D split problem with creased edges

I’m trying to make a shelled building in rhino with Sub D. However where the two main parts join rhino makes it pointy. I want it to be smooth. is there any way I can accomplish this without making the model overly complicated? I added pictures and a file of the problem.
sub d schil 2.2 12-1.3dm (105.4 KB)



Thx for the reply, however this isn’t the problem. I understood what you did however I don’t want the U shape on the inside. I want it to be a sharp V on the inside and the surfaces to be smooth. On the outside I made a test peace next to it with the same topological problem
sub d schil 2.3 12-1.3dm (122.8 KB)

I found the problem in the simplest form but I don’t know how to resolve it.
sub d problem.3dm (61.6 KB)
It seems it isn’t possible to make a sharp inside corner with continuous material around it.


so i made a file with two halves and the problem is that the way the curves are made they are not the same. Any way to resolve this?
sub d schil 2.3 13-1.3dm (138.7 KB)

can you post an image of what your desired outcome is? Hard to decipher without some sort of visual-

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So I made the model first from nurbs, however then I’m not able to easily manipulate it. So I wanted it to be a Sub D. Here is the model in which the problem isn’t occuring because it is in nurbs.
desired outcome.3dm (466.1 KB)
desired outcome.pdf (1.0 MB)
I managed to minimize the effect, however when you zoom in, you can see that the surface isn’t smooth. I would like it to be completely smooth

so i want a sharp cutout to the corner of the first model but without losing this smooth curvature.


well yes but then there is a crease on top of the roof. I think it might have something to do with the normal lines being flipped?

you can also see in the wireframe that the surfaces reach the point in a very strange way.

similar if you look at the control points when the subd is transformed into nurbs

You just need to work carefully, and everything will work out. What I showed you, I did in 10 minutes, rough work.
Well, you still need to learn the basics of modeling on SubD, here on the forum there are links to excellent literature and background information on how to get smooth polygons.