Model federation is the practice of bringing separate models together, usually one per discipline or zone, so they can be viewed, checked and coordinated as one. The models are linked, not merged: each remains a separate file owned and updated by its own task team. The combined view is called the federated model.
At a glance
| Inputs | Shared models from each task team (native or IFC) |
| Done in | Coordination software, model viewers or the CDE |
| Who manages it | The BIM or information coordinator of the lead appointed party |
| Frequency | Each coordination cycle, often weekly |
| Requires | A shared coordinate system and an agreed model breakdown |
Why federate instead of merging
- Ownership stays clear: every element belongs to one author, who is responsible for it.
- Files stay a manageable size and teams work in parallel.
- Updates are simple: a team shares a new revision and the federated model picks it up.
- Different software can work together, especially through IFC.
The model breakdown
The BEP sets out how the project is split into models, called the volume strategy or model breakdown. Common splits:
| Split by | Example |
|---|---|
| Discipline | Architecture, structure, mechanical, electrical, plumbing, civils |
| Building or zone | Block A, block B, car park, external works |
| Level | Basement, podium, tower (on tall buildings) |
| System | Drainage, fire protection, vertical transport |
The split affects file size, ownership and clash tests, so it is agreed early and rarely changed.
Weekly coordinationRepeat every cycle until the stage is coordinated
1Share modelsChecked, in the CDE
6Fix in own modelsEach task team
7Verify and closeIn the next shared model
The coordination cycle
- Task teams share their models in the CDE at the agreed time.
- The coordinator loads them into the federated model and checks they line up.
- Clash tests and checks are run; results are grouped into issues.
- Issues are discussed at the coordination meeting and assigned.
- Teams fix their models and share again.
Common problems
- Models that do not line up, because teams used different origins or did not apply the shared coordinates.
- Elements modelled twice by two disciplines (for example, structural walls in both architecture and structure models) with no rule about who owns what.
- Old revisions in the federation, because the coordinator loaded files from email instead of the CDE.
- Links inside native models loaded again in the federation, producing duplicates.
Where to read more
The BEP's model breakdown and coordination procedures set the rules. Coordination software documentation explains how each tool appends, updates and aligns models.