As you can see, the seat in our butterfly chair is made up of rectangular segments. If you want to increase the number of segments in the mesh,you can change the Surftab1 and Surftab2 system variables. Surftab1 controls the number of segments along edge 1, the first edge you pick in the sequence; and Surftab2 controls the number of segments along edge 2. AutoCAD refers to the direction of edge 1 as m and the direction of edge 2 as n. These two directions can be loosely described as the x- and y-axes of the mesh, with m being the x-axis and n being the y-axis.
the setting for Surftab1 is 24, and for Surftab2 the setting is 12. The default value for both settings is 6. If you would like to try different Surf tab settings on the chair mesh, you must erase the existing mesh, change the Surf tab settings, and then use the Edge Surface too again to define the mesh.