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BIM modelling of a steel structure in Revit

Case study: Haute-Nendaz ski lift station

Not all steel structures are equally complex. A standard industrial hall is usually based on a regular grid of columns and beams. A ski lift station, on the other hand, presents a completely different challenge.

Over the decades, these structures are constantly evolving. Mechanical equipment is replaced, platforms are modified and structural frames are reinforced, whilst successive alterations gradually cause the building to diverge from its original documentation. The plans then become insufficient to provide a precise understanding of the building’s current condition.

As part of the project to replace the cable car between Tracouet and Haute-Nendaz, it was essential to have a reliable representation of the structure before the design work could begin. The 3D laser scan survey, followed by BIM modelling in Revit, enabled the existing buildings to be faithfully reconstructed, thereby providing a common working basis for all parties involved. This approach corresponds to the scope described in our tender, comprising the survey of the two stations, LOG 250 modelling of the buildings and steel superstructures, and the delivery of the BIM files and drawings derived from the model.

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An overview of the steel structure at Haute-Nendaz station, modelled in Autodesk Revit using a 3D laser scan. The BIM model depicts the framework, load-bearing elements and the main technical systems of the infrastructure.

Maquette BIM sous Autodesk Revit de la structure métallique de la gare de remontées mécaniques de Haute-Nendaz réalisée à partir d’un relevé laser scanner 3D.

This study presents the BIM modelling of an existing steel structure, based on a 3D laser scan survey of the Tracouet–Haute-Nendaz cable car stations in Switzerland. The data acquired enabled the creation of a digital model in Autodesk Revit at LOG 250 level, incorporating the load-bearing structures, the steel framework, the roofs, the main technical installations and the architectural volumes. The deliverables include, in particular, RVT, IFC, DWG and PDF files, as well as the point cloud in E57 format. This methodology provides a reliable basis for projects involving the renovation, conversion or replacement of technical infrastructure.

An infrastructure that goes far beyond a simple steel framework

When people think of a steel structure, they often picture a relatively simple industrial building. A ski lift station, however, is a very different story.

The supporting structure houses particularly large mechanical equipment, technical areas spread across several levels, maintenance platforms, ancillary spaces, as well as numerous modifications carried out during successive modernisation projects.

Every intervention alters the structure locally without necessarily updating the existing documentation. After several decades of use, it becomes difficult to distinguish between what was part of the original project and what has been added subsequently.

In this context, a precise understanding of the existing situation becomes an essential prerequisite for any study.

An overview of the BIM model of the Haute-Nendaz ski lift station. This digital representation, developed in Autodesk Revit using 3D laser scan data, depicts the architectural volumes, roofs and main structural elements of the existing infrastructure.

Vue générale de la maquette BIM sous Autodesk Revit de la gare de remontées mécaniques de Haute-Nendaz, réalisée à partir d‘un relevé laser scanner 3D de l’existant.

Capturing reality without interpretation

Both stations were surveyed using a 3D laser scanner to produce a point cloud covering both the architectural features and the visible steel structures.

The survey does not seek to interpret the building: it produces an extremely accurate three-dimensional representation of it. Distortions, geometric variations, unusual joints and subsequent alterations are recorded directly during the data acquisition process.

This approach enables the various stakeholders to work on a shared representation of the current situation, rather than on a series of plans that may be incomplete or contradictory.

From millions of points to a usable BIM model

Once the data acquisition is complete, the various scans are merged to form a single point cloud.

This stage enables all the buildings to be reconstructed within a coherent system in which each element retains its actual position. The point cloud then serves as the basis for the entire BIM modelling.

The model developed in Revit is not merely a graphical representation. It organises information in such a way as to make the building understandable and usable by architects, engineers, technical consultancies and contractors.

Model the steel structure in LOG 250

Opting for the LOG 250 level of detail meets the needs of the majority of renovation projects.

The main structural elements are modelled with a level of detail appropriate for BIM coordination: columns, beams, roof trusses, roofs, walls, slabs, openings and the main visible services are incorporated into the digital model. For this project, the steel superstructures and the roof of the upper station have also been modelled in order to retain the elements intended to be retained in the future project.

This approach provides a model that is detailed enough for research purposes whilst keeping production times within reasonable limits.

Detailed view of the BIM model highlighting the steel structure, service ducts and the main equipment incorporated into the Revit model.

Détail de la structure métallique modélisée sous Autodesk Revit montrant les portiques, les passerelles techniques, les escaliers et les équipements de la gare de Haute-Nendaz.

A common working framework for all stakeholders

The value of a BIM model goes far beyond simply producing drawings.

Architects have a reliable tool for their refurbishment projects. Engineers can analyse existing structures. Specialist firms coordinate their technical installations within a shared environment, whilst contractors prepare their work based on geometry that accurately reflects the building.

La maquette de la structure métallique Revit devient ainsi un langage commun entre tous les acteurs du projet.

Deliverables tailored to current BIM methods

The data produced can be used at various stages of the project.

Depending on requirements, they are delivered as E57 point clouds, Revit models (RVT), IFC files for open BIM exchanges, and 2D drawings extracted directly from the model in DWG and PDF formats. A virtual tour can also be included to facilitate communication between teams.

Conclusion

The Haute-Nendaz project perfectly illustrates the value of laser scanning when applied to complex engineering structures. Where historical records prove insufficient, 3D scanning provides an objective representation of the existing structure.

BIM modelling in Revit then transforms this information into a genuine decision-making tool. More than just a model, it serves as a coordination tool designed to support every phase of the project, from the initial design stage right through to the completion of the works.

Detail from the BIM model illustrating the modelling of the curved metal cladding, the connecting footbridge and the main architectural features of Haute-Nendaz station.

Détail de la maquette BIM sous Autodesk Revit montrant le bardage métallique, la passerelle de liaison et l’enveloppe architecturale de la gare de Haute-Nendaz.
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Key takeaways

3D laser scanning is currently the most reliable method for documenting an existing steel structure prior to refurbishment. Combined with BIM modelling in Autodesk Revit, this approach enables the creation of a digital model that is true to life and can be used directly for design, technical coordination and preparation of the works. In the case of Haute-Nendaz station, this approach enabled the modelling of the buildings, the steel superstructures and the main technical installations, thereby providing a common working basis for all parties involved.

Yes. Laser scanning enables the creation of an accurate BIM model based on the building’s actual condition, even when the plans are incomplete or out of date.

Autodesk Revit facilitates BIM coordination between the various parties involved and enables the creation of both a digital model and the 2D drawings required for the design work.

The LOG 250 level is suitable for the majority of renovation projects. Simpler or more detailed levels can be produced depending on the project’s requirements.

Deliverables generally include the point cloud (E57), Revit (RVT) files, IFC, DWG and PDF files, and, where required, a virtual tour.

Tel : 031 552 00 28
BIM model and 3D survey of a historic building in Lausanne