LOD 100 to LOD 500: what "Level of Development" really means
LOD (Level of Development) describes how reliable and detailed a model element is at a given stage, from a rough placeholder (LOD 100) to a verified as-built record (LOD 500). Most junior modeling work happens at LOD 300 to 350, where size, shape and location are accurate enough for coordination.
What LOD means
LOD answers one question: how much can someone rely on this element? A box representing a future air handling unit is fine for early planning but useless for clash detection. A fully dimensioned AHU with connection points is what coordination needs. LOD gives everyone a shared vocabulary for that difference.
Each LOD, with an example
| LOD | Description | Example: a supply duct |
|---|---|---|
| 100 | Conceptual. A symbol or mass showing something will exist. | An area marked "HVAC zone". |
| 200 | Approximate size, shape and location. | A generic duct with an assumed size. |
| 300 | Specific size, shape, location and orientation. Measurable. | A 900 × 450 duct at a defined bottom level, routed correctly. |
| 350 | As 300, plus interfaces with other systems. | Duct with hangers, connections and clearance zones shown. |
| 400 | Fabrication-ready detail. | Duct split into fabrication segments with joints and fittings. |
| 500 | Field-verified as-built. | Duct position confirmed on site after installation. |
LOD vs LOI
LOD is often used loosely to mean "level of detail" (geometry), but the information inside the object matters just as much. That is LOI, Level of Information: manufacturer, model number, airflow, fire rating, maintenance data. A model element can have high geometric detail and little data, or the reverse. Projects following ISO 19650 define both explicitly.
Which LOD at which project stage?
- Concept design: mostly LOD 100–200.
- Detailed design and coordination: LOD 300, rising to 350 around interfaces.
- Shop drawings and fabrication: LOD 400.
- Handover: LOD 500 as-built models for facility management.
What it means for you as a junior modeler
Most training and internship work sits at LOD 300 to 350. That means your sizes must be correct, your levels must be accurate, and your elements must connect properly, because the model will be clash-tested. It also means you should not waste hours modeling bolts on a duct hanger unless the BEP asks for LOD 400.
Knowing the target LOD before you start a task is one of the simplest ways to look experienced.
Week 2 of the BIM Crafter curriculum covers BIM concepts and LOD 100–300 before you start modeling systems on real datasets.
See the curriculum