At an Oct. 14 conference in Charlotte, N.C., for power-users of 3-D design technology, executives and developers from Bentley Systems Inc., Exton, Pa., unveiled a tool they call an i-model, which they described as both an “elaboration” of a DGN file and as a “container” for encapsulating, circulating and re-incorporating 3-D design information and other project data of any format involved in a workflow of review and collaboration.

Unlike other 3-D model combining, viewing and reviewing tools, an i-model’s components retain their original geometric precision and “provenance,” or self-describing information about their formats, standards and sources, say Bentley officials. They can be created in a stand-alone environment, but if exported from, and later returned to the new release of Bentley’s ProjectWise Navigator V8i (Select Series 1), a collaboration server-based file management system, that provenance can be used to automatically return proposed adjustments and notations made by reviewers working disconnected from the model, back to the original features in the model under review. An audit trail of commentors is included.

For example, a notation made on an i-model in the field about an interference at one of hundreds of gusset plates in a design will take the model manager directly to the gusset plate in question when the i-model is returned to the project, and it will tell them who proposed the modification and when, and bring along notations.

“The i-model composer can be a desktop application and pull in sources from anything and produce an i-model. Or it can be server-based where it can automatically create or recreate i-models as a routine according to whatever rules you may have set up,” says Joe Croser, Bentley’s global marketing director for platform products and subscriptions.

Model contents are locked and can be timed to expire to ensure that only current data is shared. They can carry full digital rights management and digital signatures.

Stand-alone software to view i-models is free. Extending the abilities to review and comment, simulate schedules or run clash detection can be added incrementally. Croser says the cost of giving all of those capabilities to each member of a team of 50 users would come to $16,200.

The Oct. 14 presentation was met by a roomfull of expert users with a flood of questions. Their answers generated nods and smiles and comments like “game changing,” although most approached afterward said their companies would not let them comment for publication. However, Samir Emdanat, director of virtual design and construction at Ghafari Consulting, Dearborn, Mich., called it a “...very interesting approach,” after mulling the implications a few days. He says he is setting up a server to test the product.

The development of the i-model leverages a June 2008 agreement between Bentley and Autodesk to expand interoperability between their portfolios of architectural, engineering, and construction software by exchanging software libraries, including Autodesk RealDWG. Since so many of their customers use combinations of software from both companies on large projects, the companies agreed to work together to improve their abilities to read and write their respective DWG and DGN formats in mixed environments. They also agreed to support the reciprocal use of their application programming interfaces to improve work process interoperability. Bentley has used that to deliver the first free i-model creator, a plug-in for Autodesk Revit, which will let Revit users create i-models directly from inside that program. Bentley says plug-ins for other third-party products soon will be available and will release the code needed for third-party development as well.

“We think the i-model is conceptually right,” says Greg Bentley, CEO. “This will be the container to bring design collaboration to the AEC workflow, long term.”