Licensing options for this format begin with FME Desktop Professional Edition.
FME provides a reader for Design files used by the Bentley® Map, MicroStation, and Intergraph Interactive Graphics Design System (IGDS).
This format is an extension of the Bentley Microstation Design format. This chapter assumes familiarity with Microstation Design files, and the Bentley Microstation Design format.
For more information on Design file support in FME, please see the Bentley Microstation Design format documentation.
Overview
This format reads a XFM Feature focused representation of the XFM data found in Design files which are associated with the Bentley Map application. The XFM data in design files represent an instance of XFM feature and property information as a part of a Bentley Map project. The Bentley Map project defines a schema for XFM features, and the properties of those features, as well as the domains for those properties among other things.
The XFM Design Reader interprets this XFM data and merges the XFM feature properties present with the related graphical elements in the Design file. This results in a schema which includes the XML properties for each XFM Feature, and data features which have XFM properties values and graphics that together represent XFM feature instances. This is done with the limitation that XFM features which are composed of complex elements will only be represented by either the complex element or the components.
Alternatively, the DGN V8 Reader has been enhanced to support reading XFM data in a normalized way by representing XFM data as separate graphics and properties features. The DGN V8 Writer has been enhanced to write data which has been produced by either the DGN V8 Reader or this XFM Design Reader. In either case when writing, care should be taken that transformation of XFM data does not violate the overall coherency with the Bentley Map project. See the Microstation Design Format for more information. Note that XFM features which are composed of complex elements may not be represented completely enough by the reader to be reconstructed identically by the DGN V8 Writer.
Note: There are two versions of XFM data: one using attribute linkages and associated with Bentley Select Series 1 Design files, and a second using XAttribute attributes and associated with Bentley Select Series 3 and newer Design files. The DGN V8 Writer currently only writes XFM data in the Select Series 1 form.
Reader Overview
The XFM Design Reader extracts each individual element, one at a time, and passes it on to the rest of FME for processing. If the element had any attribute linkages or Xattributes attached to it, these are read and added as attributes to the FME feature being created. XFM attributes contain UUIDs (Universally Unique Identifiers) are used to match standard Design file elements with XFM Feature instance data. Other XFM attributes contain element identifiers as references which are similarly used to match other elements with XFM Feature instance data.
The results of such matches are merged into FME feature which represent Bentley Map Feature instances. This corresponds to XFM Design Reader schema which is the sum of all the Bentley Map Features instances found in the Design file.
When the XFM Design Reader encounters an element type it does not know how to process, it simply ignores it and moves on to read the next element. When an XFM feature instance is found that does not match another graphical element in the Design file, the feature is still read. Such features for Select Series 1 data have the igds_type attribute set to igds_xfmstore and are all placed on the default level. Similar features for Select Series 3 data have have the igds_type attribute set to either igds_polygon_collection or igds_nongeom collection.
For more information on general Design file elements, how they are read, or their representations inside FME, please see the documentation on the Bentley MicroStation Design format.