BIM coordination is the process of combining the discipline models of a project (architectural, structural, mechanical, electrical, plumbing, and others) into one federated model, and using it to find and resolve conflicts between the disciplines before construction. Its purpose is to move collisions from the job site, where they cost rework and schedule, into design, where they cost a model change.
How the process works
- Discipline models. Each design discipline, and increasingly each major trade contractor, maintains its own model of its scope.
- Federation. On a set cadence, the models are combined into a federated model: one viewing environment containing everyone's geometry, without merging authorship. Model exchange follows the project's agreed formats and, on projects run under ISO 19650, moves through the common data environment.
- Clash detection. Software checks the federated model for conflicts: hard clashes where objects occupy the same space, and clearance clashes where required access or tolerance space is violated. Raw clash counts run high and are triaged; most are duplicates, modeling artifacts, or trivial.
- Coordination meetings. The recurring meeting where triaged issues are reviewed, assigned, and tracked to resolution. Issues are managed in a log, often exchanged in open formats built for the purpose, and each resolution lands back in a discipline model.
- Sign-off. Areas or systems are declared coordinated, at which point trades can fabricate and install against them with confidence.
Who runs it
On design-build and CM-at-risk projects, the general contractor or construction manager usually leads coordination through a VDC (virtual design and construction) or BIM manager, since the builder owns the consequences of field conflicts. On design-led projects the architect may lead during design, with the builder taking over as trade models arrive. Either way, coordination is a standing process with an owner, a cadence, and a log, rather than a one-time model check.
Coordination versus clash detection
Clash detection is the software step inside the wider process. Running a clash test is minutes of computing; coordination is the human work of deciding which clashes matter, who moves, and confirming the fix. Projects that equate the two tend to produce long clash reports and few resolved conflicts. The distinction matters when evaluating tools and staffing: the software finds intersections, and the process resolves them.
Why it pays
Spatial conflicts found in the field interrupt crews, generate RFIs and change orders, and ripple into schedule. The same conflicts found in the model are absorbed into normal design iteration. Coordination is one of the most direct forms of constructability assurance a project can buy, and on dense projects (hospitals, labs, plant rooms) it is effectively mandatory.
Related terms
- Constructability: the broader buildability discipline coordination serves.
- ISO 19650: the information management framework coordination runs inside on compliant projects.
- CDE: where models and coordination information are exchanged.
- RFI: where uncoordinated conflicts surface during construction.
- AEC: the industry context.
Frequently asked questions
What is BIM coordination in simple terms? Combining every discipline's 3D model into one shared model, finding where they conflict, and resolving the conflicts before construction starts. It replaces field surprises with model fixes.
What is the difference between BIM coordination and clash detection? Clash detection is the automated check that finds geometric conflicts. BIM coordination is the whole process around it: triaging results, assigning fixes, running coordination meetings, and confirming resolutions in the models.
Who is responsible for BIM coordination? Commonly the builder's VDC or BIM manager on design-build and CM-at-risk projects, since the builder bears field conflict costs. Leadership can sit with the design team during early phases and shift as trade models join.
What is a federated model? A combined model assembled from each discipline's separate model for viewing and checking, without merging them into one file. Each discipline keeps authorship of its own model; federation is how they are examined together.
When should BIM coordination start? As soon as two disciplines have geometry that can conflict, and no later than design development for the primary systems. Trade-level coordination continues into construction as fabrication models arrive.
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