Hi I am using Rhino 7 and I have an issue I am trying to delete segments of a subd but the hold model changes when I do so I have drawn in black the lines as a guid to how I want it to be
If I understand correctly you want to remove some faces of a SubD, but without changing the shapes of the remaining faces?
You can crease the new boundary vertices, which will keep the edge sharper, though it won’t go back to the shape before the faces were removed.
I believe it is not possible to remove faces and leave the remaining ones unchanged, because of how subdivision surfaces work with vertices affecting the shape of adjacent faces.
An alternative could be to convert it to NURBS first then remove just the patches you want.