To select a surface alignment

To assign the alignment of surface objects to a face or the centerline of the surface, use the following procedure.

Select one or more surfaces that will have the same alignment.
Tip: Surface alignment is set with respect to the local axes of the surface object. You can display the local axes by selecting the Local Axis tool in the Toggle Attributes group on the View ribbon tab.
On the Surface ribbon tab, select the Alignment tool in the Properties group.
Select the alignment option from the drop-down menu:

Center - default alignment with nodes at the center of the surface thickness

or
Top - aligns the connecting nodes with the top face of the surface

or
Bottom - aligns the connecting nodes with the bottom face of the surface

You can use the same process to edit the surface alignment.

You can also make changes to surface alignment selection by selecting the Properties tool in the Surfaces group on the Spreadsheet ribbon tab.