Level of Development (LOD)

What the BIM Level of Development stages — LOD 100 through 500 — mean for a model's geometry, data, and how much you can rely on it.

Level of Development (LOD) is a framework that defines how much geometric detail and information a BIM element contains at a given stage of design. It was formalised by the American Institute of Architects (AIA) and is widely used in the US; similar frameworks (e.g. LOI/LOG in the UK) exist internationally. LOD lets teams communicate clearly about what a model can and cannot be relied on for.

📌

LOD is about reliability, not detail for its own sake

Higher LOD means a model element can be used for more decisions — cost estimating, coordination, fabrication — not just that it looks more detailed on screen.

LOD 100 — Conceptual

Elements are represented symbolically or as approximate massing. They show that something exists and roughly where, but not what it actually is.

Geometry is approximate — correct overall volume and location, not accurate dimensions
No specific material, assembly, or manufacturer data
Suitable for: feasibility studies, site massing, early cost-per-m² estimates
Cannot be used for: quantity take-offs, coordination, or construction

🏗️

Example

A wall modelled as a single solid box with no thickness breakdown. A floor slab shown as a flat plane. A structural column as a generic cylinder at the right grid intersection.

LOD 200 — Schematic / Design Development

Elements are modelled as generalised systems with approximate size, shape, location, and orientation. They represent the design intent well enough to coordinate between disciplines.

Geometry is approximate but believable — correct thickness, height, and position
Generic material or assembly type assigned (e.g. "exterior wall", "concrete slab")
Quantities can be extracted but carry an allowance for error (~10–15%)
Suitable for: design coordination, early clash detection, SD/DD cost estimates
Cannot be used for: fabrication, shop drawings, or precise material scheduling

🏗️

Example

A wall modelled at the correct thickness with a generic stud-wall assembly. A structural beam at the right depth and width, assigned as "W-section steel" but without a specific size. Ductwork routed with correct diameter but no fittings.

LOD 300 — Detailed Design / Construction Documents

Elements are modelled with accurate geometry, precise dimensions, and specific assemblies or products. The model is reliable enough to produce construction documents directly from it.

Geometry is accurate — dimensions, offsets, and clearances are correct
Specific assembly, material layers, or product type defined
Quantities are reliable for procurement and tendering
Openings and inserts are positioned correctly
Suitable for: construction documents, accurate quantity take-offs, detailed cost estimating
Cannot be used for: fabrication, or full multi-trade coordination without LOD 350 connection detail

🏗️

Example

A wall with defined layer composition (gypsum board / 140mm stud / insulation / sheathing), correct height and length to the mm, with window and door openings positioned accurately. A steel beam specified as W310×97 at the correct elevation and size — but how it connects to its columns is not yet modelled (that arrives at LOD 350).

LOD 350 — Coordination

LOD 350 sits between 300 and 400. It adds the interfaces between systems — how elements connect, support, and attach to one another across disciplines. The AIA introduced it in 2013 because the jump from 300 to 400 was too large for multi-trade coordination: teams needed connection geometry to clash-check properly, but not yet full fabrication detail.

Geometry includes connections, supports, and interfaces between elements
The parts needed to coordinate with other trades are modelled — brackets, connection plates, penetrations, hangers
Quantities and clash detection are reliable across disciplines, not just within one
Suitable for: multi-discipline coordination, detailed clash detection, trade sign-off before fabrication
Cannot be used for: fabrication without further LOD 400 detail (welds, fasteners, tolerances)

🏗️

Example

The same W310×97 steel beam, now showing its connection plates and bolt groups where it meets each column, plus the penetration where a duct passes through it — enough to clash-check structure against MEP, but without weld specifications or fabrication tolerances.

LOD 400 — Fabrication & Assembly

Elements are modelled in enough detail to be fabricated and installed directly — the shop-drawing level. This work is typically authored by fabricators and specialty contractors rather than the design team.

Geometry includes fabrication detail: connections, fasteners, welds, tolerances, and assembly sequence
Specific manufacturing and installation information is attached
Quantities are exact, down to individual fixings and offcuts
Suitable for: shop drawings, fabrication, prefabrication, and on-site installation

🏗️

Example

The steel beam specified with exact weld sizes, bolt grades and hole positions, camber, and a coating spec — a model element that can be sent straight to the fabricator to cut and assemble.

LOD 500 — As-Built / Verified

LOD 500 is the field-verified record of what was actually constructed. It is not a design stage — it is a verification state, where geometry and data are confirmed against the built work (often via survey or laser scan) and handed to the building owner.

Geometry and data are verified against the constructed asset, not just designed
Records actual installed sizes, locations, products, and serial numbers
Suitable for: facilities management, operations and maintenance, asset handover, and digital-twin baselines
Note: LOD 500 is about verification and record-keeping, not added design detail

🏗️

Example

After construction, the beam's as-installed position is confirmed by survey and the model is updated with the actual product, supplier, and installation date — feeding the building owner's facilities-management system.

Quick comparison

LOD	Geometry	Data	Typical use
100	Approximate massing	None / symbolic	Feasibility, concept cost
200	Generalised, approximate dims	Generic type / assembly	Coordination, SD/DD estimate
300	Precise, accurate dims	Specific assembly / product	CDs, quantity take-off, procurement
350	Precise + connections & interfaces	Specific + connection data	Multi-discipline clash detection & coordination
400	Fabrication-level detail	Manufacturing / install info	Shop drawings, fabrication, installation
500	Field-verified as-built	Verified actual products / data	FM, operations, asset handover

Most architectural design work targets LOD 300; structural and MEP coordination commonly reaches LOD 350; LOD 400 is fabrication territory owned by trades; and LOD 500 is the verified as-built handed to the owner. New to the bigger picture? See What is BIM?