BIM Terms Explained: BIM, LOD, ISO 19650, IFC, BEP and Clash Detection
Updated 2026-09-03 · TaskBider research
Quick answer
BIM (Building Information Modelling) means designing and building from a shared data-rich 3D model. LOD (Level of Development) grades how reliable each element is, from LOD 100 concept to LOD 500 verified as-built. ISO 19650 is the international information-management standard for BIM projects. IFC is the open exchange format published by buildingSMART. A BEP (BIM Execution Plan) is the contract document stating how BIM will be delivered. Clash detection is the automated conflict check run weekly in Navisworks, Solibri or Autodesk Construction Cloud by the BIM Coordinator.
| Term | One-line meaning | Where you meet it |
|---|---|---|
| BIM | Building from a shared data-rich 3D model | Revit, ArchiCAD, Tekla |
| LOD | How reliable an element is, LOD 100 to LOD 500 | Scope of work, per stage |
| ISO 19650 | International BIM information-management standard | Public and EU/UK tenders |
| IFC | Open vendor-neutral BIM exchange format | Client deliverable lists |
| BEP | Plan stating how BIM will be delivered | Bid and post-award documents |
| Clash detection | Automated conflict check across disciplines | Weekly coordination cycle |
Why these six terms decide whether you get hired
Job ads for BIM Coordinators, BIM Modelers and MEP Modelers rarely test software clicks. They test whether a candidate can read a scope of work that says 'LOD 350 at Stage 4, IFC 4 exchange, ISO 19650 naming, weekly clash cycle' and price or plan the work correctly. Getting one of those wrong is what causes rework.
- LOD sets how much detail you owe — modelling to LOD 400 when LOD 300 was bought is unpaid work.
- IFC 4 is normally required alongside native files, so exports must be tested early, not at handover.
- ISO 19650 naming and the Common Data Environment decide where files live and who approves them.
- The BEP overrides personal habits: coordinate system, units, worksets and issue cadence all come from it.
Frequently asked questions
- What is BIM in simple terms?
- BIM (Building Information Modelling) is designing and building from one shared 3D model that carries data as well as geometry — materials, dimensions, cost and schedule. Architecture, structure and MEP teams model in Revit, ArchiCAD or Tekla, then federate those models in Navisworks or Solibri so conflicts surface before site work starts.
- What is ISO 19650 in simple terms?
- ISO 19650 is the international standard for managing project information when working in BIM. It defines who produces what, a Common Data Environment for storing it, strict file naming, and the Exchange Information Requirements that trigger each delivery. Parts 1 and 2 cover delivery, Part 3 covers asset operation and Part 5 covers security.
- What does LOD (Level of Development) mean in BIM?
- LOD (Level of Development) states how trustworthy a modelled element is, from LOD 100 conceptual massing to LOD 500 verified as-built. LOD 300 means correct size and position for coordination; LOD 350 adds interfaces between systems; LOD 400 adds fabrication detail used for shop drawings. Contracts should name a target LOD per discipline and stage.
- What is a BIM Execution Plan (BEP)?
- A BEP (BIM Execution Plan) is the document that says how BIM will actually be delivered on a project: software versions, shared coordinate system, file naming, model division, LOD per stage, clash-detection cadence and sign-off responsibility. Under ISO 19650 a pre-appointment BEP goes in with the bid and is confirmed after award.
- What is clash detection and who runs it?
- Clash detection is the automated check that finds physical conflicts in a federated model — a duct crossing a beam, a pipe through a wall. The BIM Coordinator runs it, usually weekly, in Navisworks, Solibri or Autodesk Construction Cloud, then issues a clash report and tracks every item to close-out with the responsible discipline.
- What is IFC and why do clients ask for it?
- IFC (Industry Foundation Classes) is the open, vendor-neutral BIM format published by buildingSMART, currently at IFC 4. Clients ask for IFC deliverables so models remain readable without a specific software licence, and so archives outlive one vendor's file format. Native files such as .rvt are normally required alongside the IFC export.