Applink problem

Hallo, tell me pleas why when I Applink to 3D Coat(import model for per pixel painting), and tourn on Subdivide in 3D coat import dialog, model subdevided but not smooth? For example I import cube, and it subdivided but still with sharp corners?

Possibly Smooth groups.

Before you send cube, change to "Polygon selection", and use "Smooth Group" -> "Smooth All"

Yep, it works! Thank you) Tell mepleas where I can read about smooth groups? I really do not know what is it.