What does LOD mean in BIM? Level of Development (LOD) tells the project team how far they can rely on a model element, not how detailed it looks. The current reference is the BIMForum LOD Specification 2025, released December 31, 2025[1]. Most design models are built to LOD 300. Construction coordination needs LOD 350. Fabrication and shop drawings are LOD 400. LOD 500 is a field-verified as-built condition, not a level above LOD 400[2]. In Georgia, the University of Georgia requires BIM on projects with total funding of $5 million or more[6], GSFIC publishes a BIM Guide for state projects that require BIM[4], and Georgia DOT lets its first project with the model as a legal deliverable on December 17, 2026[8].
Key Takeaways
- LOD measures reliability. BIMForum separates Level of Development (how far the geometry has been thought through) from Level of Detail (how much is drawn)[3].
- LOD 300 is not clash-free. The 2025 specification says so directly. Coordination-ready elements are LOD 350[2].
- LOD 500 is not “higher” than 400. It describes field-verified existing or as-built geometry, with accuracy stated[2].
- UGA: BIM is required on projects with total funding of $5 million or more, with Revit .RVT as the deliverable format and COBie data at closeout[6].
- GSFIC: where BIM is required, the A/E delivers IFC plus native files and a clash report at preliminary and final design[4].
- GDOT: 3D models are required on projects with earthwork, and the first Model as Legal Deliverable project lets December 17, 2026[7][8].
- Local permits: Atlanta’s permitting is fully electronic, but it reviews plan sets, not models[14].
LOD Is About Reliability, Not Detail
The most common misunderstanding of LOD is that a higher number means a prettier or more detailed model. BIMForum draws the line clearly: Level of Detail is how much detail is included in a model element, while Level of Development is “the degree to which the element’s geometry has been thought through” and “the degree to which project team members may rely on the information when using the model”[3].
That distinction matters when you write a contract. A highly detailed door family can still be LOD 200 if its size and location are placeholders. A plain box can be LOD 300 if its dimensions and location are designed and measurable. The base LOD definitions come from AIA Contract Document E201-2022, and BIMForum’s specification expands them element by element[2].
LOD 100 to 500: What Each Level Means
| LOD | What the element is | What you can rely on it for | Typical phase (UGA standards) |
|---|---|---|---|
| 100 | A symbol, generic representation, or space reservation. Information is approximate[2]. | Massing, early cost per square foot, feasibility | Conceptual design[6] |
| 200 | Generic 3D placeholder with approximate quantity, size, shape, location and orientation[2]. | System sizing and layout options; approximate quantities | Schematic and preliminary design[6] |
| 300 | Designed element whose quantity, size, shape, location and orientation can be measured[2]. | Design intent, construction documents, measured quantities | Construction documents[6] |
| 350 | LOD 300 plus measurable interfaces with adjacent elements[2]. | Construction-level coordination and clash resolution | Coordination (design-build or CM) |
| 400 | Detail sufficient for fabrication, assembly and installation[2]. | Shop drawings, prefabrication, field installation | Shop drawings[6] |
| 500 | Existing or as-built condition from observation or field verification, with accuracy stated[2]. | Renovation design, record models, facility management | As-built and record[6] |
Sources: BIMForum LOD Specification 2025, Part I[2]; University of Georgia standards, July 1, 2026[6]. The LOD 350 phase is our description; UGA’s list does not include LOD 350.
Two LOD Misreadings That Cost Money
1. Treating LOD 300 as coordinated
The 2025 specification adds plain language that “LOD 300 elements are not necessarily clash-free” and notes that designers rarely model above LOD 300[2]. If your scope says “LOD 300 model” and you expect a clash-free model for the trades, the contract and the expectation do not match. Specify LOD 350 for the systems that must be coordinated, and name who resolves clashes.
2. Treating LOD 500 as the top of the scale
Several BIM provider pages describe LOD 500 as the highest level. BIMForum says explicitly that LOD 500 “does not indicate a higher level than LOD 400”; it means the geometry was determined by observing an existing item[2]. For existing buildings, ask for a stated Level of Accuracy. BIMForum recommends the USIBD Level of Accuracy (LOA) Specification for this[2][13].
What Georgia Public Owners Require for BIM
GSFIC (state construction projects)
The Georgia State Financing and Investment Commission’s BIM Guide, dated March 1, 2013, applies wherever BIM is required as a deliverable, and also where a solicitation prefers BIM capability and the design firm is selected on that basis. It sets no dollar threshold[4]. At preliminary and final design submissions it asks for:
- A single IFC file (IFC 2×2 preferred, or IFC 2x) plus the native model files[4]
- Separate discipline models linked to a central file, in U.S. customary units at a 1/8-inch tolerance[4]
- An internal clash check, with the clash report uploaded with the model[4]
- Surveys tied to Georgia State Plane West, NAD83 (1991)[4]
GSFIC’s 2023 Design Review Group Process Guide confirms that where BIM is required, it is in addition to all current design submission requirements[5]. Note that IFC 2×2 is a retired version; the current version is IFC 4.3, published as ISO 16739-1:2024[10]. Confirm the version with the GSFIC project manager before export.
University of Georgia
UGA’s design and construction standards (July 1, 2026) state that “BIM is required on all projects with total funding of $5 million or greater” and encouraged on all others[6]. The native Revit .RVT file is the deliverable format, a BIM Execution Plan is due within 30 days of the design contract award, and facility data is delivered in COBie spreadsheet format[6].
Georgia DOT
GDOT’s 3D Modeling Guide requires a 3D model on projects with earthwork or grading, such as widenings, roundabouts, interchanges and bridge replacements. The model is submitted with the preliminary and final field plan review packages and with final plans for letting. Models given to bidders are “for information only,” and the 2D plans remain the contract documents[7].
That is starting to change. Beginning with the March 2026 letting, GDOT added further 3D deliverables to final plans on projects with earthwork, and its first Model as Legal Deliverable project, PI 0016469 (SR 6/SR 101 at Coots Lake in Polk County), is scheduled for the December 17, 2026 letting. On that project, specific elements of the digital model become contract deliverables alongside the traditional plans[8]. GDOT’s October 2025 digital delivery roadmap proposes a statewide BIM Execution Plan and open IFC and LandXML standards[9].
City of Atlanta and local permits
The City of Atlanta has moved to a fully electronic permit process through Accela Citizen Access[14]. Its permitting pages describe electronic plan submittals; they do not mention model submittals. For private projects in Metro Atlanta, the sealed 2D plan set remains the permit and contract document. A model is how you produce that set and keep it consistent, as we explain in our guide to BIM for civil site design.
How to Write a BIM Scope That Gets You a Usable Model
Most BIM disputes start with a one-line scope such as “provide a Revit model.” A usable scope answers these eight questions:
- What is the model for? Clash detection, quantity takeoff, rezoning exhibits, fabrication, or facility management. Each use drives a different LOD.
- What LOD, for which elements, at which phase? Use the BIMForum element tables rather than one LOD for the whole model[2].
- Which file formats? Name the native format (for example Revit .RVT), the IFC version, and the clash report format[6][10].
- Which coordinate system? Tie the model to the survey. GSFIC requires Georgia State Plane West, NAD83 (1991)[4].
- How are clashes reported and closed? State the tolerance, the tool, the report format and who resolves each clash.
- How accurate are existing conditions? For renovations and scan-to-BIM, require a stated Level of Accuracy under the USIBD LOA Specification[13].
- Is the model a contract document? On most projects it is not. GDOT’s Model as Legal Deliverable project shows how that is changing[8].
- What data does the owner need at closeout? If the owner runs a facility management system, specify COBie, as UGA does[6].
What Drives the Cost of a BIM Model
We could not find an independent, methodology-backed benchmark for BIM modeling cost. The per-square-foot figures published online come from BIM vendors’ own marketing pages. What reliably moves the price:
- Building area and complexity: floors, systems and how unusual the geometry is
- Disciplines modeled: architectural, structural, framing, MEP, civil/site
- LOD by element: LOD 350 and 400 elements take much longer than LOD 200 placeholders
- Existing conditions: working from scans or field verification versus clean drawings
- Coordination scope: number of clash review rounds and the people who attend them
- Deliverables: quantity takeoffs, IFC and COBie exports, renderings, sheets produced from the model
For Mack Engineering’s typical model cost range and what is included, see our BIM services page.
Is BIM Worth It? What the Survey Data Says
The best-known figures come from industry surveys, so they reflect what firms report, not measured outcomes. In Dodge Data & Analytics’ 2021 SmartMarket Report, 64% of contractors reported a high or very high reduction in rework during construction, and 62% of designers reported a high or very high reduction in errors and rework[11]. In Dodge’s 2020 research on BIM for MEP, multi-trade contractors reported 49% fewer RFIs during construction[12]. At the industry level, NIST estimated in 2004 that poor interoperability cost the U.S. capital facilities industry $15.8 billion a year[15].
Modeling is not worth it on every project. On a flat pad with a simple utility tie-in, a good 2D set is enough. The test we use: if one field conflict or one hearing continuance would cost more than the model, build the model.
Get a BIM Scope Built for Your Georgia Project
Mack Engineering builds coordinated Revit models from our office in Alpharetta for owners, builders, developers and design teams across Metro Atlanta and Georgia. Send us your plans and tell us what the model needs to do, and we will tell you what LOD and deliverables it actually needs. See our BIM services in Atlanta or call (770) 715-7295.
Frequently Asked Questions
What LOD is a typical design model?
Most design models are built to LOD 300, which BIMForum describes as sufficiently developed to fully convey design intent. BIMForum notes that designers rarely model elements above LOD 300, and that LOD 300 elements are not necessarily clash-free.
Is LOD 500 higher than LOD 400?
No. BIMForum states that LOD 500 does not indicate a higher level than LOD 400. LOD 500 means the element’s geometry comes from observation or field verification of an existing or as-built condition, with its accuracy stated.
What is LOD 350 used for?
LOD 350 adds measurable interfaces with adjacent elements, which supports construction-level coordination. BIMForum notes it usually requires craft knowledge from the trades, so it is common on collaborative and design-build projects.
Does Georgia require BIM for state projects?
There is no blanket statewide requirement. GSFIC’s BIM Guide applies wherever BIM is required as a deliverable on a GSFIC project, and the University of Georgia requires BIM on projects with total funding of $5 million or more. Georgia DOT requires 3D models on projects with earthwork.
Can I submit a BIM model for a building permit in Atlanta?
The City of Atlanta’s permitting process is fully electronic through Accela Citizen Access, but its permitting pages describe plan submittals, not model submittals. The sealed 2D plan set remains the permit document; a model can produce and coordinate that set.
What file formats should a BIM scope require?
Name the native authoring format (for example Revit .RVT), and an open IFC export with its version. If clash review is part of the scope, also name the clash report format. The current IFC version is IFC 4.3, published as ISO 16739-1:2024.
Sources
[1] BIMForum, Official Release: 2025 LOD Specification (Dec. 31, 2025). https://bimforum.org/official-release-2025-lod-specification/
[2] BIMForum, Level of Development (LOD) Specification 2025, Part I. https://bimforum.org/wp-content/uploads/2026/01/LOD-Spec-2025-Part-I-Official.pdf
[3] BIMForum, Level of Development (LOD) Specification 2024, Part I. https://bimforum.org/wp-content/uploads/2024/11/LOD-Spec-2024-Part-I-official-English.pdf
[4] Georgia State Financing and Investment Commission (GSFIC), BIM Guide, Series 01 (Mar. 1, 2013). https://gsfic.georgia.gov/document/publication/building-information-modeling-bim-guide/download
[5] GSFIC, Design Review Group Process Guide (rev. Apr. 28, 2023). https://gsfic.georgia.gov/document/document/design-review-process-guide-2023pdf/download
[6] University of Georgia, Design & Construction Supplemental General Requirements (July 1, 2026 standards). https://www.architects.uga.edu/sites/default/files/pdf/standards/2026/03-Supplemental%20General%20Requirements.pdf
[7] Georgia DOT, 3D Modeling Guide, Rev. 1.0. https://www.dot.ga.gov/PartnerSmart/DesignManuals/OtherResources/3D%20Modeling%20Guide.pdf
[8] Georgia DOT, Notice to Contractors on 3D deliverables and Model as Legal Deliverable (copy via GovTribe). https://govtribe.com/file/government-file/notice-to-contractors-dot-pdf-107
[9] Georgia DOT / FHWA, Digital Delivery: Roadmap for Implementing BIM for Infrastructure at GDOT (Oct. 2025). https://rosap.ntl.bts.gov/view/dot/87360/dot_87360_DS1.pdf
[10] buildingSMART International, Industry Foundation Classes (IFC). https://www.buildingsmart.org/standards/bsi-standards/industry-foundation-classes/
[11] Dodge Data & Analytics, Accelerating Digital Transformation Through BIM, SmartMarket Report (2021). https://damassets.autodesk.net/content/dam/autodesk/www/pdfs/aec-smart-market-report-2021-bim-digital-transformation-en.pdf
[12] Dodge Data & Analytics, BIM for MEP SmartMarket findings (2020), Autodesk infographic. https://damassets.autodesk.net/content/dam/autodesk/www/pdfs/adk_bimmep_infographic.pdf
[13] U.S. Institute of Building Documentation, Level of Accuracy (LOA) Specification. https://usibd.org/level-of-accuracy/
[14] City of Atlanta, Online Permitting. https://www.atlantaga.gov/government/departments/city-planning/zoning-development-permitting-services/online-permitting
[15] NIST, Cost Analysis of Inadequate Interoperability in the U.S. Capital Facilities Industry, GCR 04-867 (2004). https://nvlpubs.nist.gov/nistpubs/gcr/2004/NIST.GCR.04-867.pdf