A new challenge in design: BIM (Part 2: the ifc format)

In our last post, we have dealt with BIM and introduced its potentialities in the field of timber constructions. Today we are going to discuss the IFC exchange format and its applications.

What is the IFC?

The IFC file (Industry Foundation Classes) is a format which is totally neutral, because it does not belong to one specific service provider; developed in 1994 by the International Alliance for Interoperability (today’s BuildingSmart, a worldwide authority driving the transformation of the built asset economy through creation and adoption of open, international standards), it aims to simplify the exchange of information among the disciplines involved in the design process, and thanks to that it is widely used in BIM.

All the most important CAD softwares using BIM technology have a IFC-export functionality. In a typical .ifc output file, every object is linked to data such as, for example:

• Name
• Type
• Section (geometry)
• Volume and surface
• Position, Elevation
• Material
• Mechanical properties

…and so on.

The visualisation software BimVision (Datacomp) shows data related to the selected beam.

The strength of IFC can be easily explained looking over the tutorial of the BIM visualisation and support software Tekla Bim Sight (developed by Harpaceas S.r.l.), in which a number of models representing different aspects of the building (structure, MEP, envelope) are shown: these models can be gathered in a shared directory (a sort of ‘BIM Cloud’) and displayed at the same time. It is the so called Model Checking phase: in real time, clashes are found, files are updated and comments and tips can be left.

Some screenshots taken from the Tekla Bim Sight (Harpaceas S.r.l.) tutorial, in which various IFC models are overlaid to form the design of a building.

Clashes between structural and MEP models, found thanks to BIM.

As an example, one of our technicians might need to associate a foundation (created with a software like Tekla Structures, specialised in concrete and steel structures) to a timber structure made with HSBcad; by means of other softwares like Archicad or Allplan, a building envelope could be added, and so on. With BIM, all the requirements of the design process are gathered on a single platform, from whom all the needed data can be extracted.

Grafting of steel and concrete objects, made with Tekla Structures, on a timber sample structure, modelled with HSBcad.

BIM is quickly spreading in construction companies all over Europe, but only 10% of professionals uses it in Italy. Why is BIM so little known in Italy? What are its limits?

1. ‘Thinkin’ BIM’ means investing in top-notch hardware, expensive software licenses, and training. These initial expenses, actually, would help save a lot of money in the future. BIM gives value to a professional’s work, but Italian customers (especially local administrations) do not acknowledge it.
2. While architecture of Northern Europe promotes simple and standardised designs, in Italy there’s a different mentality and, consequentially, it is more difficult to handle BIM CADs, optimised for modular structures.
3. The IFC format. On the market, there are many CAD softwares that use BIM technology and can develop complete models, but the next step (the interactions among models generated by different softwares) is still being experimented. The IFC format is continuously evolving, and this can create compatibility issues.

Despite these limits, BIM offers great advantages:

1. High precision;
2. Possibility of estimating the costs of materials, even at early stages;
3. Possibility of pre-ordering specific customised elements;
4. Maximum interactions among professionals (architect, construction engineer, MEP specialist, planning supervisor, and so on) before the construction stage of the design process.
5. Reduced time of construction.

Why must we all learn BIM.

The 2014/24/EU directive on Public Contracts says, at clause n. 22 c.4:

 ‘For public works contracts and design contests, Member States may require the use of specific electronic tools, such as of building information electronic modelling tools or similar.’

From 2016 onwards, member States must promote the use of BIM for EU-funded projects, to increase the effectivity and transparency in contract procedures.

It is clear that, despite its current limits, BIM represents the future the world of constructions and civil engineering are aspiring to. Therefore, it is our due, as professionals, to invest in training. Just because most of our colleagues don’t intend to abandon traditional methodologies, it does not mean that we can hesitate any further.

At Ergodomus, we already make use of BIM for our works. And what about you, is your company ready for BIM?

Written in collaboration with Francesca Bifulco, engineer and post-graduate degree in Timber Engineering, University of Bologna.