To smooth surface meshes with the Sculpt Geometry brush
The Sculpt Geometry Tool options appear and the Maya cursor changes to a brush icon to indicate it is now in sculpting mode.
When the Operation is set to Smooth, the Max Displacement and Reference Vector (X, Y, Z) options are respected. That is, the smoothing will be constrained based on what Reference Vector option is set and limited by the Max Displacement value.
To apply a smooth action to the entire mesh at once
The Flood operation applies the specified settings over the entire surface or mesh.
To progressively smooth a model, use the Flood button with Smooth as the selected operation, and set the opacity low.