OpenMW is a free, open source and modern engine based which reimplements and extends the one that runs the 2002 open-world RPG Morrowind. The engine comes with its own editor , called OpenMW-CS which allows the user to edit or create their own original games. Both OpenMW-CS and OpenMW are written from scratch and aren’t made to support any third party programs the original Morrowind engine uses to improve its functionality.

You still need the data files from Morrowind to use OpenMW.