Dear Glen :
RiverCAD 2000 can read in MicroStation drawing files if you first save the MicroStation drawing file (*.DGN) as a DXF or DWG file. RiverCAD XP (too be released soon) supports most native MicroStation DGN files. To create a DXF or DWG file from MicroStation, select File | Save As, and then change the file type to be either a DXF or DWG file. Note that RiverCAD can work with contours, TINs, grids, break lines, and other 3D entities that might be part of the MicroStation drawing file.
If you have any additional questions or need any further information, please contact me again.
Sincerely,
Chris E. Maeder, M.S.
Senior Technical Engineer
chris.maeder@bossintl.com