IFC Alignment

An important aspect for the success of BIM is the availability of open standards for the lossless exchange of high-quality building information models between software applications from different manufacturers. As part of the OpenINFRA intitiative of buildingSmart, the IFC Alignment project has been started. The IFC Alignment project aims at developing a neutral data model for capturing the alignment of linear infrastructure facilities as a basis for the future IFC Infrastructure standard, which will include data structures for describing roads, bridges and tunnels, thus providing means for exchanging semantically rich 3D models of this kind of facilities.

The first step towards developing an IFC Infrastructure was made between April 2013 and March 2015 as part of the IFC Alignment project, which aimed to develop an alignment extension for IFC. This project involved researchers from the Technical University of Munich and the French institute CSTB, as well as companies such as AEC3 Germany and Bentley Systems. The project was funded by the public organizations Trafikverket from Sweden and Rijkswaterstaat from the Netherlands. To ensure worldwide acceptance of the future standard, an international expert panel was set up that accompanied the elaboration of the data model in a series of workshops. In February 2015, the data model was promoted to “Candidate Standard” status and passed successfully through the public review process. After the formal adoption by the buildingSMART Standard Commitee the data model will be raised to the state of an official standard (final standard).

IFC Alignment serves as a description of road and rail alignments. The model is based on the well-established approach of aligning design based on vertical (gradient) and horizontal alignments. The underlying conceptual model was developed in cooperation with the OpenGIS Consortium (OGC). IFC Alignment was developed based on this model. In the future, in the context of OGC, the InfraGML standard will be developed that is based on the Geography Markup Language (GML). The jointly developed conceptual model also acts here as a common basis.

At present, the following buildingSMART International (bSI) projects are currently in preparation: IFC Rail, IFC Road, and IFC Bridge. All three projects will use IFC Alignment as a common foundation. Furthermore, an extension project of IFC Alignment is planned which will be named IFC Alignment 1.1. In the context of IFC Alignment 1.1, new transition curves will be introduced, such as Bloss-curves, as well as a uniform way of referencing an alignment. This will, for example, make it possible to bind cross sections of a road to certain station values of the corresponding alignment. Finally, offset alignments are also planned as part of the IFC Alignment 1.1 project.

The official buildingSMART IFC Alignment landing page can be found here: http://www.buildingsmart-tech.org/infrastructure/projects/alignment




EXPRESS Schema: IFC4_P6_longform_draft5.exp

EXPRESS Schema (with minor syntax correction): IFC4_P6_longform_draft5_withMinorSyntaxCorrection.exp

 Test data


The TUM Open Infra Platform (OIP) has been developed by the Chair of Computational Modeling and Simulation at the Technische Universität München for viewing alignment and digital elevation model data. OIP supports several file formats for alignment and digital elevation data. It has export and import functions for IFC Alignment, LandXML, and OKSTRA. 


▪  Rampf, F.:
Development of an IFC Alignment Import/Export Plug-in for Autodesk AutoCAD Civil 3D
Betreuer: Borrmann, A. and Amann, J.
Bachelorarbeit, 2017

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▪  Vilgertshofer, S.; Amann, J.; Willenborg, B.; Borrmann, A.; Kolbe, T.H.:
Linking BIM and GIS models in infrastructure by example of IFC and CityGML
In: Proc. of the ASCE International Workshop on Computing in Civil Engineering 2017, Seattle, USA, 2017

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▪  Markič, Štefan:
IFC-Bridge: Previous Initiatives and Their Proposals
In: Proc. of the 29th Forum Bauinformatik, Dresden, Germany, 2017

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▪  Amann, J.; Borrmann, A.:
Embedding Procedural Knowledge into Building Information Models: The IFC Procedural Language and Its Application for Flexible Transition Curve Representation
Journal of Computing in Civil Engineering 30 (4), pp. 1-14, 2016
DOI: 10.1061/(ASCE)CP.1943-5487.0000592

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▪  Amann, J.; Borrmann, A.:
Creating a 3D-BIM-compliant road design based on IFC alignment originating from an OKSTRA-accordant 2D road design using the TUM Open Infra Platform and the OKSTRA class library
Technische Universität München, 2015

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▪  Amann, J.:
Einbettung von prozeduralem Wissen in Produktdatenmodelle am Beispiel der Richtlinien für die Anlage von Landstraßen mithilfe der Programmiersprache IFCPL
In: Proceedings of the 27th Forum Bauinformatik, Aachen, Germany, 2015

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▪  Singer, D.:
Einsatz wissensbasierter Methoden in frühen Phasen des Brückenentwurfs
In: Proceedings of the 27th Forum Bauinformatik, Aachen, Germany, 2015

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▪  Singer, D.; Borrmann, A.:
A Novel Knowledge-Based Engineering Approach for Infrastructure Design
In: The Fourth International Conference on Soft Computing Technology in Civil, Structural and Environmental Engineering, Prague, Czech Republic, 2015

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▪  Schwöbel, J.:
Free-Sketching Ansätze in der Trassenmodellierung
Betreuer: Amann, J.
Forschungsarbeit, 2015

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▪  Amann, J.; Borrmann, A.:
Open BIM for Infrastructure – mit OKSTRA und IFC Alignment zur internationalen Standardisierung des Datenaustauschs
In: Tagungsband zum 6. OKSTRA-Symposium, Köln, Deutschland, 2015

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