geometry
{
    Cyclone-inlet.stl
    {
        type triSurfaceMesh;
        name Cyclone-inlet;
    }

    Cyclone-outlet.stl
    {
        type triSurfaceMesh;
        name Cyclone-outlet;
    }
    
    Cyclone-wall.stl
    {
        type triSurfaceMesh;
        name Cyclone-wall;
    }    
};

• These lines defines the input geometry (usually .stl or .obj which are placed in /constant/triSurface directory).

    features
    (
          {
              file "Cyclone-wall.eMesh";
              level 1;
          }
    );

• In block features the feature-edges generated by surfaceFeatureExtract utility could be defined together with the level of refinement.

    refinementSurfaces
    {
        Cyclone-inlet
        {
            // Surface-wise min and max refinement level
            level (1 2);

            // Optional specification of patch type (default is wall). No
            // constraint types (cyclic, symmetry) etc. are allowed.
            patchInfo
            {
                type patch;
            }
        }
        Cyclone-outlet
        {
            level (1 2);
            patchInfo
            {
                type patch;
            }
        }
        Cyclone-wall
        {
            level (1 2);
            patchInfo
            {
                type wall;
            }
        }        
    }

• This block defines new boundaries using the entries from the block geometry, its level of refinement and type.