Дожили.. в хелп тяжело заглянуть? или просто на модификатор тыкнуть?
To apply MeshSmooth to an object:
Select an angular object.
Apply the MeshSmooth modifier.
Set MeshSmooth parameters.
To apply MeshSmooth to sub-objects:
Select an object.
Apply a Mesh Select modifier.
Select a group of vertices or faces.
Apply MeshSmooth.
In the Subdivision Method rollout, turn off Apply To Whole Mesh.
This lets MeshSmooth work only on the sub-object selection.
Set MeshSmooth parameters