Any time Bentley Map opens a DGN file it evaluates the contents and defines feature classes for the graphics. The following types of features may be found.

• XFM-DGN features. Those created by the Bentley Map XFM system. These can be DGN based features created by XFM placement tools or features extracted from a spatial database. The business property data is stored in the DGN.
• XFM-RDBMS features. Also created by the Bentley Map XFM system however the properties have been defined to reside in an external database such as Oracle or Access. The behavior of XFM-DGN and XFM-RDBMS features is the same
• Unsupported Features. These are MicroStation element types that are not currently modeled in the XFM environment. They include such elements as surfaces, solids, meshes and dimensions.
• Inferred Features. Features not explicitly defined as Native XFM features are inferred. There are a number of ways features are inferred

  Level	By default, simple elements are defined as features based on their level name. For elements inferred as features using level names, the feature's class name is set to that of the level name (after changing invalid feature name characters to the underscore character). If the level name begins with a number then it is prefixed with "Level_". If level name retrieval by level id fails then the feature name is: "Level_" + levelID. This behavior may be turned off by setting configuration variable MS_GEOXFM_NO_LEVELFEATURES.
  Cell Names	Cells are assumed to represent separate feature classes based on their name. For elements inferred as features using cell names, the feature's class name is set to that of the cell name (after changing invalid feature name characters to the underscore character). If the cell name begins with a number then it is prefixed with "Cell_". For example: "Cell_4Pole". Orphan cells with cell elements on multiple levels have their feature name prefixed with "Cell_" followed by the level id. For example: "Cell_48" where 48 is the level id. Orphan cells with all elements on the same level have feature name of that level name (prefixed with "Level_" if name starts with a number). For example: "Pole", "Level_4Pole" This behavior may be turned off by setting configuration variable MS_GEOXFM_NO_CELLNAMEFEATURES.
  MicroStation GeoGraphics Features	If a MicroStation GeoGraphics project was converted to a Bentley Map project using the Import tool in Bentley Geospatial Administrator then a number of rules would have been created to help Bentley Map determine how to recognize those features. Those rules become part of the project and key off of the MSLINK number defining the feature code.
  Session Features	The command manager may have an entry entitled session features. These are features that have been recognized by Bentley Map but are not part of the feature definitions defined by the active XFM project. When session features are created, default placement and edit methods are also created. These can be used to create new session feature instances and, if business properties are present, edit them.