Level of development (LOD)

EstablishedLOD

Also: LOD 350

A numbered scale (LOD 100–400, plus 500 in some frameworks) describing how far a model element's geometry and information have been developed — and therefore how much other team members can rely on it.

Explanation

The BIMForum Level of Development Specification, updated annually (latest 2025), interprets the AIA's basic LOD definitions element by element, organised by CSI UniFormat. It defines LOD 100, 200, 300, 350 and 400; LOD 350 adds interfaces with neighbouring systems needed for detailed coordination. LOD 500, where used, refers to field-verified representation and is defined in contract documents rather than as a further step in geometric development.

The key idea is reliability: LOD describes what a user downstream may rely on, not how much graphical detail is visible. A highly detailed manufacturer object placed in an early design model is still only as reliable as the design decisions behind it.

Practical example

In the model element table of a hospital BEP, ductwork is required at LOD 200 at schematic design, LOD 300 at construction documents and LOD 350 for the trade coordination model, so that hangers and penetrations can be coordinated before fabrication.

Why it matters

LOD tables give North American contracts a shared shorthand for model expectations at each milestone, and they define what others may rely on, which matters for risk allocation.

Common confusion

LOD is ambiguous: it can mean level of development (this entry) or level of detail. ISO 19650 practice uses Level of information need instead. See the comparison page.

Historical context

Level of development was introduced in AIA contract documents in the late 2000s, drawing on earlier "level of detail" scales used in software practice. BIMForum began publishing its element-level specification in 2013 and has updated it regularly since.

Standards and references

  1. Level of Development (LOD) Specification. BIMForum, 2025.Widely accepted professional interpretation
    Supports: LOD Specification based on AIA LOD definitions, organised by CSI UniFormat; latest version 2025; content and reliability of model elements

VDC Stack.io writes its own explanations and does not reproduce copyrighted standards text. Consult the cited standard for normative wording.

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VDC Stack.io. (2026). Level of development (LOD). In VDC Stack.io Knowledge Dictionary. Retrieved from https://vdcstack.io/dictionary/level-of-development/