I’m experimenting with subsurface modifiers, and don’t understand the following behavior.
I created my object by duplicating the default cube twice, joining them, removing the inner faces (and their vertices), then rebuilding the top and bottom faces. Because my object is symmetrical, I expected the subsurf result to be symmetrical as well. Instead, the right side looks as though it has had edge creases applied.
How can I make the subsurface geometry symmetrical?