LOD in BIM Explained: LOD 100, 200, 300, 350, 400 and 500 Without the Confusion
Level of Development is not the same as Level of Detail. This guide explains LOD 100 through 500 as industry usage from AIA and BIMForum documents, what each level means in models, and how to specify LOD without treating it as a global law.
LOD in BIM is one of the most used and most mixed-up acronyms in a project brief. People say LOD when they mean how pretty an object looks, how much you may rely on it for coordination or quantities, how close it is to fabrication, or how complete a whole building is. Those are different ideas. This guide keeps them apart. It explains Level of Development as industry usage associated with the American Institute of Architects (AIA) documents and the BIMForum Level of Development Specification, including the common sequence LOD 100, 200, 300, 350, 400 and 500. It does not treat that sequence as a single global law. Your contract, your client, and your country may point to those documents, to ISO concepts, or to something else. Write which one you mean.
Level of Detail is about how much geometry and visual texture an element shows. A highly detailed furniture family can be visually rich and still unreliable for cost or coordination. A simple wall with the correct type, location and fire rating can be visually dull and highly reliable for those uses.
Level of Development is about how much you are authorised to rely on the element’s information and geometry for a stated use. In BIMForum/AIA-related usage, higher LOD means more authorised reliability, not merely more polygons. A project that pays for high Level of Detail without defining Level of Development is paying for pictures.
Do not write “LOD” in a brief without expanding it once as Level of Development, and do not use Level of Detail as a silent synonym. If you need both, write both.
These documents are widely referenced in industry practice. They are not a statute that every jurisdiction has enacted. They are not ISO 19650, though a project can use both. They are not a Singapore regulatory instrument. If your contract says “LOD 300 as BIMForum,” that is a contractual pointer. If your contract says only “LOD 300,” you still need to say whose definition you are using, or people will download a blog post and argue.
BIMForum published a specification that many teams use for examples by element. AIA documents such as E202 historically framed LOD concepts in US practice. Always read the edition your contract names. This article summarises common usage in plain language; it is not a substitute for those publications.
In common usage, LOD 100 is a conceptual or massing representation. A block that says “there is a volume here” or a symbol that says “a system exists.” You should not take quantities, clash tests of real clearances, or fabrication from it. Outsourcing “the whole hospital at LOD 100” is a massing job. It should be priced and reviewed as massing.
LOD 200
Approximate geometry and approximate location: generic walls, generic ducts, schematic plant boxes. Useful for early spatial tests and early drawings that still say “indicative.” Clash detection at LOD 200 can find that a 3 m plant cannot fit in a 2 m room if the placeholders are sized honestly. It cannot prove hanger coordination.
Buyers who want cheap 3D often want LOD 200 and then ask why quantities are wrong. Quantities at this level, if produced at all, should be labelled as indicative and excluded from contractual measurement unless the contract says otherwise.
LOD 300
Geometry suitable for typical coordination and traditional construction documents in many teams’ usage: specific sizes and locations of elements as designed, enough to generate drawings that a contractor can price and coordinate against, without claiming fabrication-level parts. A duct at LOD 300 is a duct of the designed size on the designed route, not necessarily with every hanger and seam.
This is the level people overload. They write LOD 300 and then expect LOD 400 shop behaviour, or they write LOD 300 and deliver LOD 200 generics. Your table should list examples: “AHU is a specific family with connectors and clearances; small-bore pipes below X mm excluded; hangers excluded.”
LOD 350
BIMForum usage introduced LOD 350 to capture the coordination space between “designed” and “fabrication”: interfaces with other systems, supports and connections sufficient to coordinate, not necessarily every shop ticket. MEP teams often need this language for hangers, fire damper clearances, and equipment access. If you need trades to coordinate in a ceiling, LOD 300 without 350-style interface requirements may be too thin. If you do not need that yet, do not pay for it.
LOD 350 is not a magic extra hundred. It is a statement about interfaces. Write the interfaces.
LOD 400
Fabrication and assembly level in common usage: the model can support shop drawings and manufacture of the element. Steel detailing, sheet-metal spools, and similar live here. Revit may or may not be the authoring tool. Do not demand LOD 400 from a design consultant who has not been appointed to fabricate. Do not demand it from schematic drawings. Contractor packages should name which systems go to 400 and which stay at coordination level.
LOD 500
As-built / field-verified representation in common usage: the element is a record of the constructed condition. It is not “maximum detail.” An as-built wall can be LOD 500 in the sense of verified location and type without being a mesh of every brick. Scan to BIM often aims at a specified as-built reliability, which people casually call LOD 500. Be more precise: verified how, on which date, with which tolerance. See as-built BIM and Scan to BIM.
Calling a design model LOD 500 because the project is complete is a paperwork lie if nobody measured the field.
How to specify LOD without confusing the whole building
Use a table by system and by stage. Architecture envelope, interior partitions, structure frame, structure connections, mechanical air mains, mechanical air branches, hydronic, drainage, electrical containment, equipment, site. Each cell: LOD number plus a one-line example plus exclusions. “Whole model LOD 300” is how hangers get forgotten and then demanded.
Match LOD to purpose. Drawings can come from mixed LODs if view templates are honest. Clash tests should not treat LOD 200 placeholders as installation clashes. Quantities should exclude elements below the LOD needed for that measured item.
Outsourcing and LOD disputes
Most marketplace disputes that mention LOD are actually scope disputes. The buyer thought hangers were included. The seller modelled mains only. The BEP table would have ended the argument in week one. Put the table in the project brief. Ask bidders to restate it. If they restate “LOD 400 everything,” they have not read it.
Source of definition named (BIMForum edition, contract, or project-specific)
Table by system
Exclusions listed
Clash and QTO rules aligned to the table
As-built not claimed without verification method
Writing a project LOD table that a modeller can price
A useful table has rows for systems and columns for stages (scheme, coordination, construction, record). Each cell is a number plus a sentence. Example: “Mechanical air mains at coordination: LOD 350 — sized ducts on route with insulation envelope and fire damper clearances; hangers excluded; flex limited to X metres.” That sentence can be priced. “MEP LOD 350” cannot.
Include exclusions in the cell, not in a distant footnote. Include the definition source in the header: “Level of Development per BIMForum Specification edition [year], used as guidance, not as a statute.” If your contract already names an edition, copy that name. If it does not, do not pretend a blog post is the contract.
Rooms, spaces, and information (not just geometry) can lag or lead geometry. If you need room names at a stage when walls are still generic, write “information: room names required; geometry: LOD 200 walls.” That is clearer than a single number.
Clash tests and quantities must follow the table
Do not run hanger clash tests on a cell that excluded hangers. Do not take off brickwork from a cell that allowed generic walls. The clash matrix and the QTO rules should cite the LOD table cells. Coordinators and estimators who ignore the table will accuse the modeller of incompetence when the modeller followed the brief. Align the documents.
4D and 5D have the same dependency. You cannot sequence fabrication pieces you never authorised at LOD 400. You cannot cost a material you never split in types. See 4D and 5D and QTO.
Scan to BIM and as-built: do not stretch 500 into a mesh fetish
For existing buildings, write verification method in the cell: “architectural envelope LOD 500-equivalent: location verified by registered cloud dated YYYY-MM-DD, wall types as interpreted from scan plus opening schedule, unseen shafts marked.” That is longer than “LOD 500” and it is honest. Visual meshes of ornamental plaster can be a separate deliverable at a high Level of Detail with a low reliance statement. Pay for what you will use.
Contractors sometimes call shop models “LOD 400” and then skip supports. If supports are required for coordination, you wanted 350-style interfaces or an explicit hanger sentence. The number never saved you; the sentence does.
National practice, ISO, and Singapore
Some clients use Level of Information Need language from the ISO 19650 ecosystem. That language asks what geometry, what information, and what documentation are needed for a purpose. You can map a BIMForum-style table into it. You should not say they are the same thing. If a client requires ISO language, write both or write the ISO fields and drop the 100–500 numbers.
Singapore official submission documents are not a BIMForum adoption act. Do not tell a QP that “LOD 300 is required by CORENET X” unless an official document you can cite says that — and this article is not that document. Keep submission mapping in the Singapore article and official PDFs. Keep LOD as a project information language.
Marketplace disputes that mention LOD
They are usually: hangers, insulation, families, typical versus unique, and as-built verification. Put those five in the table even if you love round numbers. When you post a project, paste the table. When you compare quotes, see whether the seller restated the table or replaced it with “full LOD.” Full LOD is not a cell.
Examples by system so numbers stop being abstract
Architectural interior partitions at coordination: location and type from the legend, height to the correct constraint, openings for doors, fire rating from the door/wall schedule if present; furniture excluded; decorative mouldings excluded unless they clash.
Structural steel at construction: member size as issued, location, camber if provided, connections as required by the appointment (often in a detailing tool at 400); fire protection as a separate element or as an exclusion.
Mechanical chilled water at coordination: mains and branches to the stated diameter cut-off, insulation envelope if in scope, valve assemblies as typical or unique as briefed, hangers excluded or included as the cell says.
Electrical containment at coordination: trays and ladders on route, fill not modelled unless asked, devices excluded, switchgear as a volume plus working space if in scope.
Drainage at coordination: sloped pipes where drawings give falls, stacks in shafts, buried lines only if inverts exist; do not invent.
Record/as-built envelope: verified location from scan or measure, type interpreted, unseen marked.
These sentences are what BIMForum-style tables try to teach with examples. Your project still needs your sentences. Copying a US example warehouse table onto a Singapore hospital is how hangers get lost.
LOD and drawing scales
A 1:100 plan cannot show fabrication seams. A 1:5 detail may need a different representation, sometimes 2D. LOD does not replace drawing scale. View templates should not imply that a coarse 3D is a shop detail. Shop drawings at construction LOD still need annotation. See shop drawings.
LOD and families
A family can contain multiple detail levels. That is Level of Detail inside a family, which is not the element’s Level of Development. A coordination-stage air-handling unit can be a simple box with connectors (development for coordination) and still have a fine 3D for a marketing view that you never print. Do not raise the element LOD because someone turned on Fine.
Teaching clients who equate LOD with percentage complete
Percent complete of a model is a zone map: typical floor done, plant room not started. LOD is reliability of elements. A model can be 100% modelled at LOD 200 and still be 0% useful for hangers. Report both. Marketplace sellers who say “80% LOD 400” are mixing the two and should be asked to redraw the sentence.
LOD 300 versus “can we build from this”
Teams argue whether LOD 300 is enough to build. The answer is in the cell’s sentence, not in the number. If hangers and submitted equipment are excluded, you cannot fabricate from it. If they are included, you may be closer to construction. Stop arguing the number. Argue the sentence. Put the sentence in the BIMProSG brief.
Mixed LOD in one view
A plan can show LOD 350 ducts and LOD 200 furniture. View templates and filters should make that honest. A client who sees Fine furniture may think the ducts are fabrication-ready. Graphic honesty is part of LOD management. Presentation views should be labelled if they show mixed reliability.
LOD for civil and site objects in a building model
Roads, retaining walls, and drainage inverts may be in another model. If they appear in the building BIM as context, their LOD cell should say “context only, not for civil quantities.” Otherwise an estimator might take them off twice or wrongly.
Updating LOD as the project proceeds
Raising a cell is a scope change. Lowering a cell because drawings never matured is also a change and should be written so clash tests are not asking for hangers that were descoped. Version the table. Date it.
LOD and manufacturer placeholders
A placeholder box can be LOD 200. A submitted unit with connectors and access can be a construction cell. Replacing one with the other is a scope event. Do not leave the placeholder and call it 400 because the 3D view is Fine. The cell is about reliance, not shading.
Communicating LOD to non-BIM clients
Use examples: “We can clash the main ducts; we cannot fabricate hangers yet.” Avoid a lecture on AIA history in a steering committee. Put the history in the BEP appendix and the example in the slide. BIMProSG briefs to specialists should still name the definition source so they do not pick a random blog.
When a seller says “full LOD,” ask them to fill your table. If they cannot fill it, they cannot price it. If they will not fill it, they are selling a slogan. BIMProSG buyers should attach the table to the posting.
CTA: attach an LOD table to the brief
Before you hire or buy a service, attach a one-page LOD table. If you cannot write it, make that page the first milestone with a coordinator. Do not pay for “high LOD” as a feeling.
FAQ
Is LOD 350 mandatory? No. It is part of a widely used specification. Use it if you need interface-level coordination language.
Is LOD the same as ISO Level of Information Need? No. ISO 19650-related practice uses Level of Information Need as a broader idea of geometry plus information plus documentation for a purpose. Projects may map LOD tables into that idea. Do not assume they are identical.
Can one element have two LODs? Geometry and information can progress differently. If they do, write it. Do not hide a rich family with empty parameters behind a high LOD number.
Does Singapore law require BIMForum LOD? No. Official submission rules are separate. Do not invent a local LOD statute. See CORENET X guide.
Why do sellers love LOD 500 in ads? Because it sounds finished. Ask how they verify.
Should families be LOD-rated? Families should be suitable for the element LOD. An over-detailed family at a low element LOD is a performance problem.
Who decides LOD? The appointment and the BEP, not the clash software.
Sources and reference notes
BIMForum Level of Development Specification (various editions) and AIA LOD-related documents (including the E202 lineage) are the primary public industry sources for the 100–500 usage described here. Read the edition named in your contract. ISO 19650 series discusses information management and Level of Information Need in its ecosystem; it is not a copy of BIMForum LOD. This article is explanatory and is not a legal adoption of any of those documents.
Image brief
A table graphic of LOD 100–500 with a wall and a duct as examples, plus a warning caption: “Level of Development ≠ Level of Detail.” Do not show a photoreal brick wall labelled LOD 500 as if detail were development.