CAUTION: Caution when using User-Defined Ellipsoids and Datums

When a GCS that uses a User-defined Ellipsoid or Datum is used in a design file, that GCS will not be recognized by earlier versions of MicroStation or PowerPlatform products. If a model is opened with such a GCS in an earlier version, a message will be displayed stating that no Geographic Coordinate System is attached. Any geographically reprojected or transformed reference attachment for which the GCS of either the master file or the reference attachment uses such a GCS will not display. Such a reference will show up red in the References dialog, and when you hover over any of the fields except the file name field, the tool tip text will say “Unable to perform required Geocoordinate Transformations”.