Surface region derives a second surface from an original surface. Follow these steps to extract a region from a surface:
You must have an existing surface to extract a region from.
Use the Surface wizard or select Surface region from the surface toolbar.
Set whether to create a new surface or modify the existing surface as a sort of trim.
Name the new surface for future reference if you are creating a new surface.
Click Pick and select the source surface with the mouse, or just select the surface from the drop down list.
Enter coordinates, or pick a point on the surface to bound the row or columns on one side.
Enter coordinates, or pick a point on the surface to bound the row or columns on the other side.
Select either Rows or Columns to orient the selection region. The display highlights your selection so you can visually verify that you have the correct area selected.
Click Finish or OK to create the new surface.
An example of a surface region.