Publishing an iModel

Since the introduction of the V8i generation of applications, iModel has been the best way to package and share multi-discipline models.  They are an immutable representation which retains provenance, perfectly suited for sharing designs with project partners for bids and milestone reviews.  The introduction of the new generation of iModels, and the advancement of the iModel.js platform to its version 1.0 release, is a perfect opportunity for a quick reintroduction to this capability.

The iModel technology is of two primary types: the new generation of iModels and the I.DGN. Both have the advantage of normalizing all property data and geometry to make it more efficient and readable in a consistent way by any consuming application.  Which version you need depends primarily on how you need to structure your data and how you wish to use the iModel: whether you need to keep separate i.DGN’s for each reference file or you need a packaged iModel that would contain any of the references in one packaged file. The .iModel 2.0 format acts as an entry point to the exciting new iModel.js ecosystem which enables iTwin cloud services and mobile applications.

The capability to publish an iModel is found in Bentley View so it is available at no charge for anyone.  Bentley View opens a vast array of common file types, making it an ideal way to package and share design data.  iModel publishing is also available from MicroStation, PowerDraft, and nearly every other Bentley desktop application.

To publish an .iModel do the following:

  1. Open the Publish i-model(s) dialog (File > Publish i-model). 
  2. Turn on the Create a single package check box. (You can read about the description of all the settings available in the Publish i-model(s) dialog here.)

    This will create a single package for multiple .i.dgn files. Selecting this option will enable rest of the controls in this section.

  3. Toggle on the Create an iModel Version check box and select iModel version 2.0.

  4. Select Publish.

    The file’s location is displayed in the Message Center.


  1. A .imodel file is a transport package (which is compressed and optimized for file size) that contains a Snapshot iModel.
  2. If your design data is created in a domain-specific application, such as Open Buildings Designer, we recommend that you publish .imodel file from the same authoring application to ensure fidelity of data, properties, graphics and geometry.
  3. (For Developers) The .imodel file can be used to seed an iModelHub project using the iModel.js Testdrive registration dashboard.
  4. (For Developers) To be used by iModel.js the Snapshot iModel must be extracted from the .imodel transport package using the imodel.exe utility provided with the publishing application.

To Publish an .i.dgn file do the following:

  1. Open the Publish i-model(s) dialog (File > Publish i-model). 
    The Publish i-model(s) dialog opens.

  2. (Optional) Turn on Include Linked Design Files.
    (This setting publishes i-models of all files linked to the master file by links in Explorer or links by callouts. This only publishes the design files; non-DGN files linked to the master file are not published.)

  3. (Optional) Turn on Republish all i-models. (This option republishes the master file and its reference files, even if they have not been modified since the last time they were published.)

  4. Select a publish option from the Publish drop-down.
  5. Select Publish.

    An iModel with an .i.dgn extension is created. The file’s location is displayed in the Message Center. For example, if the fine name is Example.dgn, the published iModel file name will be Example.dgn.i.dgn.

The development of iModel.js continues at a fast pace, therefore, please visit the project site frequently. 

We hope this blog article is helpful and look forward to hearing about how you put iModels to work.