Agree the coordinate system before anyone draws a wall

The most common cause of coordination pain on UK projects is not a modelling error. It is two perfectly competent models that do not share an origin. The architectural model sits neatly on its own grid, the structural frame sits neatly on another, and when you bring them together the building is 380 metres from the drainage run. Nobody spots it until someone tries to set out on site.

Fix this at the kick-off meeting. Decide the shared coordinate system, record it in the BIM execution plan, and make sure every discipline is using the same one. In practice that usually means tying the project base point to the Ordnance Survey National Grid, confirming whether you are working to true north or project north, and agreeing a single figure for the rotation. Then test it: export an IFC from each discipline and check that grids and levels land in the same place in a clean viewer.

• Publish the shared coordinates, north angle and units in writing, and issue them with the first model drop.
• Ask each consultant to confirm in their next information container that they acquired the coordinates rather than re-typing them.
• Keep the survey model as the reference. Nobody moves it to tidy up their own view.

File naming is coordination, not housekeeping

A consistent naming convention is the cheapest coordination tool you will ever deploy. When containers follow a predictable pattern — project, originator, volume, level, type, role, number, plus revision and suitability codes — a drainage engineer can find the right structural model without a phone call or a guess. When names drift, people work from the wrong revision and you find out at the worst possible moment.

Agree the convention, agree the code list, and publish both in the common data environment so nobody is guessing. Keep the list short enough that people actually use it.

• Avoid free text in fields that are meant to hold codes. A stray comment where a suitability code belongs breaks automated checking.
• Use suitability codes honestly. A model issued for coordination is not the same as one issued for construction.
• Never reissue a model under a new name. Revise the existing container so the audit trail stays intact.

Build a review rhythm you can actually keep

Coordination dies when it is saved up for a monthly heroic session. A fortnightly, 45-minute federated model review will catch far more than a quarterly marathon, because the changes between drops are small enough to reason about. Invite one person per discipline who has the authority to change the model, not just report back to someone who can.

The coordinator federates the latest published models, checks the interaction between disciplines rather than the completeness of any single one, and circulates an agenda the day before. Keep an issues register as a live document with owners and dates attached. Decisions that live only in someone's memory have a habit of quietly reversing themselves.

• Review against a stated purpose: is this drop suitable for the structural grid check, or for services routing?
• Walk the model zone by zone. Roaming the whole building in one pass leaves the plant room unexamined.
• Record agreed actions in the model itself where you can, so the next person sees them in context.

Run clash detection with a triage mindset

Clash detection is a filtering tool, not a verdict. Run hard clashes first, then clearance checks with a sensible tolerance — 25mm around a duct is generous, 25mm around a sprinkler main is optimistic. Batch the runs by level and zone so the results are readable, and re-run only what has changed.

Expect thousands of results on a medium-sized job. The work is triage: group duplicates, discard the trivial, assign the rest. Every genuine clash gets an owner, a decision and a date. Be willing to resolve by agreement rather than redesign — a 150mm service shift is often cheaper than moving a beam.

• Separate genuine clashes from modelling artefacts such as duplicated elements or placeholder geometry.
• Prioritise by consequence, not by count. A clash above a ceiling void matters more than one inside a riser.
• Review the issue log at the start of each session. Open items that never move are usually a sign of unclear ownership.

Respect the boundaries between disciplines

The healthiest federated models are the ones where everyone knows what they own. Reference models link in and are never edited. Grids and levels have a single publishing owner. Openings, penetrations and structural zones sit with the discipline best placed to control them, and the decision is written down rather than assumed.

When something is wrong in someone else's model, raise an issue with a screenshot and a coordinate rather than quietly editing it. Silent edits cause hours of confusion when the next drop arrives and the change disappears. A short comment now is worth a site instruction later.

Finally, carry the effort forward. Record the coordinate system, the naming convention and the resolved issue log as part of your handover information. The next project on the same site will thank you, and so will the facilities team trying to find a valve in 2035.