The Model Setup IDM Georeferencing BIM IDM is aimed at all building/ infrastructure/ built asset modellers, to robustly establish the guiding model set-out parameters - map location and site configuration - for their respective asset (BIM or Digital Engineering) models. The document therefore defines a standardised way for setting up a multi-disciplinary geo-referenced project model using the IFC open standard format data. The document also defines a standard way of incorporating Cadastral data as a starting point for representing land legal ownership, zoning and planning data.

The document focusses on geo-referencing principles and includes examples for  IFC2x3,  IFC4 and IFC4x3ADD2 formats embedding geo-referencing data.

bSI maturity level

The Model Setup Information Delivery Manual (IDM) has been extended for infrastructure modellers working on projects spanning large distances where the requirements are to supply IFC files of digital engineering (BIM) data in an Earth based coordinate system such as longitude and latitude, or Map (projection) coordinates. Such data is referred to as being georeferenced.

As this is the standard for most long road and rail projects, this is often referred to as Horizontal or Linear BIM. This Information Delivery Manual adds the requirements for setting up such a multi-disciplinary georeferenced project so that data can be interchanged using the IFC 4x3 format.

Section 4: Georeferencing Vertical BIM and Section 5: Georeferencing Horizontal BIM amplify technical issues and provide extended examples now covering all the major use-cases for a majority of asset types.  Section 7: Supplying Map Coordinates Using IFC gives guidance of specific usage of the new entities.

Section 9.6 Using Georeferencing Parameters in IFC 2x3 provides naming guidelines for ePsts for all georeferencing entities required when using the IFC2x3 format (replacing the previous Table 4).

Section 10: Georeferencing Check List assists users with a comprehensive checklist of the data required for all entities.

Version 2.0 of the technical report had been re-structured as a User Guide and published in January 2020 by the buildingSMART International Building Room and buildingSMART Australasia. These are now merged into a single document.
The original version of the report was published in August 2018 with the title Model Setup IDM (Information Delivery Manual).

Opportunities addressed and created value
Initial discussions with industry identified the lack of knowledge with regards to georeferencing and the strong interest in this subject in the user base in Australia. Discussions during the project confirmed the global status of this topic, including lack of knowledge in users, and, for advanced infrastructure users, the necessity of the approach set out in the User Guide.

The IFC4x3 update extends Georeferencing capability to infrastructure developments with major contributions from the German Chapter and continued consultation from international experts.

What has been done?
The project was presented at several bSI International Summits and meetings which elicited strong support for this approach in linear infrastructure projects. In particular, at the Tokyo bSI Summit the project was presented as part of the Building Room agenda and received considerable support including that from a study undertaken in Germany.

The development and relaease of IFC4x3 required an extension of geo-referencing to support the new infrastructure asset types Roads, Railways, Bridges etc to the IFC standard.

Further recommendations
This Model Setup IDM Georeferencing BIM  IDM is a useful addition to the schema and will have direct international benefit by allowing much greater reliability for collaborative model sharing.

Attached is a discussion document [Model Setup IDM_Extensions for Georeferencing.pdf] with several suggestions for possible further improvements.

Contact

• For questions or specific feedback on the User Guide, please contact John Mitchell buildingSMART Australasia
• For more general queries and for access to the User Guide document please contact buildingSMART International