3D Coordination & Clash Detection
Phối hợp đa bộ môn & Clash Detection
Federate discipline models, detect and resolve geometric conflicts (hard/soft clashes) before construction. Track issues in BCF format.
Common tools
Navisworks Manage, Solibri, Forma (Docs & Design)
Value delivered
Stanford CIFE: up to 10% contract value savings from early clash detection. DBIA: ~10x ROI [Source: vendor/academic]
Adoption in Vietnam
Second most common use after Design Authoring in Vietnam — de facto mandatory for international projects.
Level of Information Need (LOIN)
G = Geometry · A = Alphanumeric · D = Documentation (ISO 7817-1:2024 method). A blank cell means this use sets no specific requirement for that discipline/stage.
| Discipline | Concept | Schematic | Developed | Technical | As-built / Operation |
|---|---|---|---|---|---|
| Architecture | — | G2·A1·D0 | G3·A2·D1 | G3·A2·D1 | — |
| Structure | — | G2·A1·D0 | G3·A2·D1 | G3·A2·D1 | — |
| Mechanical | — | — | G3·A1·D0 | G3·A2·D1 | — |
| Electrical | — | — | G3·A1·D0 | G3·A2·D1 | — |
| Plumbing | — | — | G3·A1·D0 | G3·A2·D1 | — |
Critical stages: Schematic · Developed · Technical
Rationale: Hard-clash detection requires G3 (clash-detectable, LOD300-350). ARCH/STRU coordinate from ST2 (soft clash at G2 catches major envelope/structure conflicts early); all MEP disciplines join at ST3 once routed. A2 + D1 by ST4 attach coordinated-status and clash-resolution attributes. This is the principal multi-discipline G-ceiling at ST3–ST4.
BIM Clash Matrix
Clash classification, the 6-discipline matrix, MEP right-of-way and the detailed BCF workflow live on the Clash Matrix page. What follows focuses on how to ORGANISE one coordination cycle.
What it really is
3D Coordination is the organisational process of federating discipline models in a shared coordinate system, detecting conflicts, then coordinating the parties to resolve them before construction. Unlike simply "running a clash test", this is organisational work: defining what counts as a clash, who owns it, what the deadline is, and confirming closure against an updated model. Finding clashes is the easy part — software does it in minutes. The value lies in filtering thousands of raw clashes down to the few that genuinely affect construction, assigning ownership and tracking to closure. It is an iterative cycle: federate → detect → assign → resolve → verify, repeated weekly until the model is clean enough to build.
When to use
For multidisciplinary projects with dense building services — hospitals, plants, towers, underground infrastructure — where spatial conflicts cause expensive demolition and rework. In practice near-mandatory for Grade I and above public-investment works, since that group must establish and operate a CDE under Art. 8(4).
Prerequisites
- •Discipline models at minimum LOIN and health — depends directly on Design Authoring
- •A shared coordinate system, agreed and verified in practice
- •A BEP defining the coordination schedule, responsibility matrix and clash rules
- •An operating CDE — mandatory for Grade I+ public-investment works
- •A named BIM Coordinator with real coordinating authority
Inputs
Discipline task teams · IFC / .rvt / .ifczip
Lead appointed party · thông số / .txt
BIM Coordinator · .xlsx
Lead appointed party · .xlsx / .pdf
Lead appointed party · .bcf
Survey task team · .rcp / .e57
Outputs
Federated model
.nwd / .ifc / định dạng nền tảng → The whole delivery team
Accepted when: Disciplines align on the shared origin; all scheduled models present
Clash report and issue register
.bcf / .xlsx / .pdf → Discipline task teams
Accepted when: Filtered and grouped, with ownership and priority assigned — not a raw dump
Coordinated model, clash-free to an agreed threshold
IFC / định dạng nền tảng → Appointing party · CDE
Accepted when: High-priority clashes closed and verified against the updated model
Coordination meeting minutes
.pdf → Delivery team
Accepted when: Each issue has a decided solution and an owner
General workflow
Receive and quality-check incoming models
Each discipline publishes on schedule to the CDE. The coordinator checks quality, purges stale links and confirms the coordinate system. Skip this and every clash result downstream is untrustworthy.
BIM Coordinator · Navisworks Manage · Forma Data Management → Models past the quality gate
Federate the models
Link every discipline model into one federated model on the agreed origin.
BIM Coordinator · Navisworks Manage · Forma Design Collaboration → Federated model
Run rule-based clash detection
Apply the agreed rule set and tolerances to each discipline pair per the coordination matrix. Clash types and their tolerances are defined on the Clash Matrix page.
BIM Coordinator · Navisworks Manage · Solibri → Raw clash list
Filter, group and prioritise
Group clashes sharing a root cause into one issue, discard noise, rank by construction impact. This step creates most of the process's value.
BIM Coordinator · Navisworks Manage · Solibri → Filtered issue register
Assign ownership and publish issues
Give each issue one owning discipline and a concrete due date; publish via BCF so every application can read it.
BIM Coordinator · Forma Design Collaboration (BCF) · BIMcollab → Assigned issues
Coordination meeting and decisions
Parties review issues in the model and decide the fix — reroute services, add a penetration, move a member — and name the doer in the room.
Facilitator + task teams · Navisworks Manage · Forma → Decision record
Task teams update their models
Each discipline edits in its own authoring tool, then moves the issue to Resolved.
Task team · Revit · Civil 3D · Advance Steel → Updated discipline model
Re-federate and verify — close the loop
The coordinator re-federates, re-runs detection, closes issues that are genuinely gone, then opens the next cycle. The remaining clash count falls with each round.
BIM Coordinator · Navisworks Manage · Forma Data Management → Model for the next cycle
Diagram
- 1. Federate — Combine models on the shared origin
- 2. Detect — Run clash rules per discipline pair
- 3. Filter & Assign — Thousands of clashes → the few that matter
- 4. Resolve — Decide the fix, disciplines update models
- 5. Verify — Re-run and close issues that are gone
Repeat until the clash count falls to a build-ready level. The number of rounds depends on project size and complexity — measure it on your own project rather than borrowing someone else's figure.
Common pitfalls
Thousands of false clashes; the team gives up on the process
Cause: Models not quality-checked, tolerances wrong, detection run too early
Fix: Put a quality gate on incoming models; tune tolerances; run only when models meet LOIN
Clashes get discussed but never close
Cause: No owner, no due date, no verification step
Fix: Every issue gets one owner and one deadline; require re-federation to verify before closing
Models drift each round; old clashes reappear
Cause: No agreed origin; each party publishes to its own convention
Fix: Standardise origin, naming convention and fixed publication dates in the BEP
Coordination meetings drag on without decisions
Cause: Issues not filtered or prioritised beforehand; no decision-maker present
Fix: Bring a pre-filtered, prioritised issue list; invite someone who can decide
A discipline publishes late and the whole cycle slips
Cause: Publication dates not bound into the BEP and TIDP
Fix: Fix the date and time, tie it to the MIDP and bind it contractually
Measuring effectiveness
Count remaining clashes after each cycle and plot over time
Benchmark: no independent benchmark — set an internal target
Issues closed by due date divided by total
Benchmark: no independent benchmark — set an internal target
Compare RFI and change order counts with and without disciplined BIM coordination
Benchmark: Stanford CIFE (32 projects): up to 40% fewer unbudgeted changes and up to 10% contract value saved through timely clash detection. Giel & Issa: RFIs down 34–68%, change orders down 37–48% across three case studies
Count cycles until the agreed clash threshold is met
Benchmark: no independent benchmark — set an internal target
Legal basis
Art. 8(5) provides that the competent construction authority uses BIM data at appraisal, including checking technical conflicts — the first time clash detection appears in Vietnamese BIM legislation. Art. 8(4) requires the appointing party to establish, manage and operate a CDE for Grade I+ public-investment works; the CDE is the infrastructure that makes the coordination cycle possible.
Sources
Only official sources (legislation, standards) and peer-reviewed academic work are cited. No vendor marketing figures or press sources. Reference only — does not replace legal advice.