The Export RockWorks Grid command allows the user to export any loaded elevation grid data sets to a RockWorks Grid (.RwGrd) format file.
When selected,
the command displays the RockWorks Grid Export Options dialog which allows
the user to setup the export. The dialog consists of a General options
panel which allows the user to set up the grid spacing and vertical units,
a Tiling panel, and an Export Bounds panel which allows the user to
set up the portion of the loaded data they wish to export.
More information about this format can be found here: https://www.rockware.com.