FBX Smoothing group

Hi guys, can someone explain me how to export smoothing group with the fbx exporter and how i set them in blender??

Closest Blender has to smoothing groups at the moment is the Edge Split modifier. Try this link.

i already know about edge split, so blender fbx at the moment don’t support smoothing group?!? the problem is that UDK support smoothing group, but as you said i can achieve the same result with edge splitter… so what is the difference? at the end with the two method each vertex is doubled… so what is the less heavy in terms of memory and cpu/gpu usage??