Blender Tutorial - Copy selected normals from mesh and export to Unity
With the Blend4Web addon it is possible to chose the normals to copy to by simply selecting them in the target mesh.
The resulting mesh can be exported to Unity in the fbx or obj format. This technique is useful for seamless splits and fun stuff like that. Feel free to ask questions if something isn't clear.
[Unintentional] [German Accent] ; )