Constructible models mean certainty

Constructible model is the latest BIM concept being mentioned everywhere, but what is a constructible model and how does it fit into the BIM process?

Andy Dickey, Tekla BIM and concrete thought leader, explains what constructible models are and why we should be using them.

What is a constructible model?

A constructible model contains the details of all elements required to effectively and efficiently convert the model to reality. A constructible model is a virtual copy of the project.

With a constructible model you get realism, which means that the model can be built. Just because something was designed or detailed doesn?t mean that it can be built – particularly when it?s in 2D. This is because 2D representations are abstractions of what is to be built, rather than accurate representations of real life.

Do you think you could recognize me from this abstract image?

AndyD AndyD

What about constructing this rebar from the 2D drawing?

3D-rebar

Why do we need realism?

We need realism in our models because ultimately it?s our money and we want to mitigate our risk, especially if we can do so easily.

Using constructible models will make building cheaper, better and faster because processes can be planned and scheduled. Possible mishaps can be detected in the design phase before construction even starts. This leads to less ad-hoc problem solving on site – which of course means cost and time savings.

Constructible models can also mitigate risk and save us money by making our estimated job cost and our actual job cost more closely match. If we use a model from preconstruction all the way through to fabrication and construction we stand a better chance of making this happen because all of the data throughout the process is coming from iterations of the same model over time.

There are two, linked, supply chains in the construction world, the information supply chain and the physical supply chain. One cannot exist or function properly without the other. The more closely the information supply chain matches the physical supply chain, the easier time all the stakeholders will have managing both. If something physical is not addressed in the information supply chain, for example bolts, then they have to be handled manually, which introduces the possibility of errors and creates a lot of work.

Realism in the information supply chain gives us more predictable outcomes and allows informed decisions earlier in the process.

Constructible model

But where do constructible models fit?

If the question is “What is BIM?” constructible models should be a part of the answer. When detailed and accurate enough, BIM should produce an information-rich model ? a constructible model.

What makes BIM and the constructible model different from the old way of working is that the one constructible model could provide the information of over 400 drawings.

Think about it, you could have a three inch stack of drawings describing a footing. One details the footing and a stack more detailing the RFIs and changes for this footing but in the model all of this information is attached to the virtual representation of the footing. With just a few clicks you can pull up all of the information regarding that footing, including the design with the rebar, RFIs and their solutions.

As you can see the constructible model brings certainty to a construction project by providing a realistic virtual model of the project. With this model we can prove that the project can be built and have a much more realistic idea of what will be required to complete the project.


AndyDAndy Dickey is the Global Business Development Manager at Trimble Solutions. Andy is an industry expert, with extensive experience in cast-in-situ concrete industry. He has also worked as a rebar detailer, concrete estimator, project manager and construction executive at various firms throughout the United States.

Andy will be visiting BuildingPoint Australia in May, so if you would like to meet up with Andy drop us a line.


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