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Construction has long relied on representations of structures for planning purposes. Technological innovation has changed how that looks and functions, though. Hand-created construction drawings have given way to computer-aided design (CAD). 2D CAD has scaled up to 3D building information modeling (BIM).  

The expansion isn’t stopping there. Today, an increasing number of architecture, engineering and construction (AEC) professionals are building on their BIM maturity. That means that instead of having multiple models — each siloed with their respective discipline — teams are combining them into a single reference that everyone can use. This integration of various models from different teams results in what’s called a federated model. 

This effort democratizes the data in the federated model, breaking down silos and making the necessary information centrally available to all parties. It’s no surprise, then, that federated models are an exciting, burgeoning field of BIM — albeit one pebbled with challenges. 

Introduction to Federated Models

Also called a combined or integrated model, a federated model pulls data from various models into one place. To remember the name “federated model,” it can be helpful to think about the way the various states in America come together to create the federal government. 

To create a federated model, someone needs to pull all of the data from all of the models that different disciplines have created into one place. This joins all of those models together so the structure can be analyzed and planned for as a whole. The result is a single unified model that better represents what will be built than any of the models individually. 

Creating a Federated Model

Some general contracting firms plan to create a federated model on their own as part of their BIM execution plan. In other instances, the owner includes a federated model requirement in the contract documents. In any instance, the creation of the model requires stakeholders across disciplines to be willing and able to share their own models.

Required Components

Assembling the necessary components to create the federated model means pulling all of the models created by various disciplines together. Most commonly, that integrates the data from the following models:

• The architectural model
• The structural model
• The mechanical, electrical and plumbing (MEP) model

The disciplines may have created multiple models within these broad categories. The structural engineering team may have developed distinct models to represent both the concrete structure and steel structure, for example. Some platforms are stronger in modeling certain categories (e.g., structural steel), which can contribute to this subdivision of model elements across platforms.   

There may also be models that solely focus on one portion of the structure rather than the project as a whole. If a certain system needs to be prefabricated, for example, the involved trade partner may have modeled that area in detail to ensure proper fit and function. 

In short, the number and scope of components that go into the federated model vary from project to project. To make the federated model as comprehensive as possible, the team tasked with assembling it should ask all involved parties to share anything they’ve modeled in 3D. That includes:

• Architects
• Structural engineers
• Trade partners
• Building service engineers

In some cases — especially in prefabrication use cases — suppliers may have done their own modeling that can contribute to the federated model. This might only come to light if a trade partner volunteers that they’ve been working with a supplier in such a way. As a result, it’s important to not just ask for model data, but also to explain the federated model and its goal to combine all modeled data in one place. This should help partners think through any modeled data that should be contributed. 

Maintaining a Federated Model

Generally, one team or individual (such as the project’s BIM manager) creates the federated model. In the United Kingdom, where there are standardized BIM protocols, the project is to designate an information manager who manages the federated information model. 

No matter who’s at the helm, this area of BIM management requires a detailed and strategic approach. For the model to be useful to the widest range of stakeholders, it needs to pull in all modeled information and keep that unified model continually updated. As a result, creating one static federated model may be insufficient. The information or BIM manager needs to have a federation strategy to pull any updates from all disciplines and integrate them into the model. 

In many cases, model data gets shared from the disciplines in a format like an .IFC file, the PDF equivalent of BIM. This enables model data sharing from one platform to another and sends a static model rather than one that’s tied to the discipline’s authoring platform. 

When a discipline updates their model, that new data usually won’t aggregate to the federated model. That means BIM and information managers need to have a procedure in place to push updates to their desk. That might mean having all stakeholders agree to the BIM execution plan, for example, which includes a clause about notification procedures when updates are made in individual models. 

As an added part of the federation strategy, it also helps to have documentation that explains any relationships between the models. Something to demonstrate their hierarchy can provide clarity and keep everyone on the same page as they leverage the federated model. 

Federated Model Use Cases in the Construction Process

Once the federated model is created, it has a variety of use cases for owners and AEC professionals.

• Visibility

  A combined model gives everyone on the project the ability to see what’s planned and align behind that plan. This can be particularly useful in streamlining communication between owners and their hired partners on the project. With a federated model, everyone can see — and agree to — the structure(s) and its components. 

• Clash Detection

  The federated model provides a useful tool for clash detection. Without all of the structure’s components included in the model, clashes might get missed. If the models from disciplines aren’t aggregated into a unified model, teams may never know that ductwork was planned where a structural beam will be installed, for example. By pulling all of the modeled data into one place, the federated model enables clash detection that’s as thorough as possible. 

• Material Takeoffs

  With a unified model, teams can perform a 3D takeoff, meaning they leverage the model to automate the creation of the list of materials required for the project. This makes the estimating thoroughly detailed without requiring any individual to spend hours, if not days, digging into the granular details. 

• Scheduling

  A federated model can also support streamlined scheduling. The hierarchy of components in the model can guide the planning around what needs to be installed when. 

• Use Once Construction Is Underway

  fter groundbreak, the federated model can continue to serve as a useful reference point for all teams (provided it stays updated). With this way to visualize the work that needs to be done and to validate completed work, the model helps the project stay on track. 

Because it unifies data and makes it available to all teams, the federated model supports collaboration and encourages transparency. 

Challenges of Using Federated Models

One of the biggest challenges in federated models stems from the current status quo around sharing model data. To transfer data from one platform to another, models usually get exported in the platform-neutral IFC format. This means exporting a static model rather than one that will push updates to other systems. As a result, information and BIM managers get tasked with continually tracking updates and integrating them into the federated model. 

Other obstacles in using federated models include:

• Confidentiality concerns when certain model components aren’t fit for sharing with all stakeholders
• The need to create ways to access the federated model in the field
• Liability issues when it’s unclear who’s responsible for sharing information that should be included in the model, when updated information needs to be distributed and the timeline and responsible party for integrating updates into the combined model

Some platforms have built measures to mitigate these concerns. They might, for example, allow certain sensitive portions of the model to be password-protected or set an expiration date for the file to encourage regular updates. 

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Driving Construction Progress with Federated Models

As the construction tech ecosystem continues to grow, individual stakeholders have an increasingly large toolbox to tap for their work. The usefulness of this tech gets limited if they’re not also looking for ways to collaborate with other individuals and teams on its usage, though. 

Federated models serve as a prime example. Individual BIM models developed by each discipline are helpful. But if they all live in their own silos, their ability to drive collaboration — and overall project success — is capped. 

By combining the data into one central model, everyone on the project gets a way to make data-informed decisions and move forward in the same direction. By connecting the data from different disciplines, the federated model enables better communication and collaboration, helping projects toward the shared goals of owners and AEC professionals.

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