When having smooth shading on a sphere and separating the top into a separate object the shading is no longer smooth over the 2 parts, there is a discontinuity:
It turns out the separate
action changes the normals:
I understand blender recalculates the normals based on the mesh it knows within the object, but is there any way to override this behavior, so that on separation, the original normals from before the separate are retained?