Level of Detail, or LOD, is one of the most frequently misunderstood concepts in BIM. Specifying the wrong LOD — either too high for the project stage or too low for the client's needs — wastes time and money. This guide explains what each LOD level means in practice.

What is LOD in BIM?

LOD defines how much geometric detail and information is required for each building element in a BIM model at a given stage of the project. LOD is specified in the Employer's Information Requirements and agreed in the BIM Execution Plan.

The LOD framework gives the project team a shared understanding of how precisely elements need to be modelled at each stage, preventing over-modelling early in the design process and under-modelling at construction stage.

LOD 100 to LOD 500 explained

LOD 100 — Conceptual. Elements represented as massing or symbolic objects conveying overall size and location. Used for early concept design and feasibility studies.

LOD 200 — Schematic. Elements represented as generic objects with approximate quantities, size, shape, and location. Used for developed design and preliminary coordination.

LOD 300 — Detailed Design. Elements modelled with specific quantities, size, shape, location, and orientation. The standard for construction document production on most UK BIM projects and the minimum level required for meaningful clash detection.

LOD 350 — Construction Coordination. Elements modelled with the level of detail needed for coordination between disciplines, including connections, supports, and interfaces.

LOD 400 — Fabrication and Assembly. Elements modelled to the level required for fabrication, manufacturing, and assembly. Used for specialist subcontractors producing fabrication models.

LOD 500 — As-Built. The model has been verified against the actual constructed state. Required for handover to the facilities manager.

LOD in UK practice

UK projects using ISO 19650 typically specify LOD requirements per element type and per project stage in the EIR. Outsource CAD works to any specified LOD and includes LOD compliance confirmation in our QA process.