MicroStation Design (DGN) Versions 7 and 8
Concept Procedure Quick Reference
 
 
 

You can import and export Microstation DGN version 7 and 8. Bentley Systems, Inc., and MicroStation programs use the DGN format. Like DWG, a single DGN file can contain points, lines, areas, text, and other object types.

Importing

Data-element information is stored in an external database file and linked to graphic objects. AutoCAD Map 3D imports database link information so you can maintain the linkage during import.

By default, object colors are imported to their closest ACI (AutoCAD Color Index) color. To import object colors using RGB (True Color), edit the mapimport.ini file.

For DGN8, the Input Layer column lists the model name. To see the layers for a specific model, you may need to scroll the list.

Driver Options for DGN 7

You can set the following options when importing DGN 7 files:

Option Description
Group Elements By Choose Geometry to group incoming objects by entity type. Choose Level to group them by their DGN level or level name. Only levels that contain elements will be imported.
Linkage Extraction Allows you to extract MSLinks and FRAMME attribute linkage values from the DGN 7 file. If you select MSLinks, AutoCAD Map 3D imports up to three links per object for DGN 7. For each link, two fields are added to the object data table: mslinks_n, which specifies the key value, and entity_num_n, which specifies the table. If you select FRAMME, the following fields are added to the object data table: comp_count, comp_num, dgnfile, feat_num, state_num, and ufid.
Coordinate Units Each DGN 7 file defines a UOR (unit of resolution); in addition, it can define Sub units and Master units. Select Master or Sub to specify which of these units in the DGN 7 file matches the default unit in the AutoCAD Map 3D map. For example, if the default unit in your AutoCAD Map 3D map is meters, and meters are the Sub unit in the imported file, select Sub. If you select Sub or Master, the UORs in the DGN 7 file are converted to Sub or Master units according to the conversion factor in the DGN file header.

When you import the file, one Master or Sub unit (whichever you choose) will become one drawing unit in your AutoCAD Map 3D map. The Unit Ratio value indicates the ratio between the Master and Sub units. For example, if the ratio is 1:12 (as it would be for Feet/Inches), imported object coordinates will be scaled 12 times bigger if you select Sub.

NoteWhen you import or export a DGN file with a master unit of Imperial feet, AutoCAD Map 3D converts the master unit from feet to meters. In addition, it does not recognize any subunit selection during the import or export process.
Element Expansion Select the options to use during import. For example, select Explode Complex Strings to return each component of a complex chain as its own feature (no feature will be returned for the complex chain as a whole). Otherwise, all elements of the complex chain merge into a single linear feature, any arcs in the complex chain become linestrings, and any linkages on the component elements themselves are lost. Select Propagate Member Linkages to return the linkages attached to the first component of the complex chain to supplement any existing linkages. Otherwise, any linkages on the component elements themselves are lost and only linkages attached to the complex chain itself are returned.
Cell Expansion By default, cells are converted into blocks, maintaining the cell grouping. You can choose to convert the cells to points instead. You can also explode the contents of the cells into their component parts, but the explosion is one level deep only.
Reference Files Select Create DWG to read all external reference files (xrefs) attached to the source data set. If the reference file has nested references, they are also imported, but circular references are not. If you select this option, you specify a location for the folder for these files. If the folder already exists, you can choose to replace it (overwrite its contents) or cancel and specify a different location. The default folder location is the same as the selected DGN file location.

If you select Ignore, reference files are not imported and you cannot change the location of the folder.

Driver Options for DGN 8

You can set the following options when importing DGN 8 files:

Option Description
Group Elements By Choose Geometry to group incoming objects by entity type. Choose Level or Level Names to group them by their DGN level or level name. Only levels that contain elements will be imported.
Cell Expansion By default, cells are converted into blocks, maintaining the cell grouping. You can choose to convert the cells to points instead. You can also explode the contents of the cells into their component parts, but the explosion is one level deep only.
Coordinate Units Each DGN 8 file can define Sub units and Master units. Specify which of these units in the DGN 8 file matches the default unit in the AutoCAD Map 3D map. For example, if the default unit in your AutoCAD Map 3D map is meters, and meters are the Sub unit in the imported file, select Sub.

When you import the file, one Master or Sub unit (whichever you choose) will become one drawing unit in your AutoCAD Map 3D map. The Unit Ratio value indicates the ratio between the Master and Sub units. For example, if the ratio is 1:12 (as it would be for Feet/Inches), imported object coordinates will be scaled 12 times bigger if you select Sub.

NoteWhen you import or export a DGN file with a master unit of Imperial feet, AutoCAD Map 3D converts the master unit from feet to meters. In addition, it does not recognize any sub-unit selection during the import or export process.
Element Expansion Select the options to use during import. For example, select Explode Complex Strings to return each component of a complex chain as its own feature (no feature will be returned for the complex chain as a whole). Otherwise, all elements of the complex chain merge into a single linear feature, any arcs in the complex chain become linestrings, and any linkages on the component elements themselves are lost.
Linkage Extraction Allows you to extract MSLinks and FRAMME attribute linkage values from the DGN 8 file. For each link, two fields are added to the object data table: mslinks_n, which specifies the key value, and entity_num_n, which specifies the table. If you select FRAMME, the following fields are added to the object data table: comp_count, comp_num, dgnfile, feat_num, state_num, and ufid.
Read Reference Files Select Create DWG to read all external reference files (xrefs) attached to the source data set. If the reference file has nested references, they are also imported, but circular references are not. If you select this option, you specify a location for the folder for these files. If the folder already exists, you can choose to replace it (overwrite its contents) or cancel and specify a different location. The default folder location is the same as the selected DGN file location.

If you select Ignore, reference files are not imported and you cannot change the location of the folder.

Other Import Options

You can set several options in the MapForeignFileProperties.ini file. See Customizing and Automating Import and Export.

See Also