Level of Development (LOD) Scale
A numbered scale, running roughly from LOD 100 to LOD 500, that describes how finished and reliable a specific element inside a BIM model actually is, from a rough conceptual shape at the low end to a verified as-built element at the high end.
Why it matters
Not every element in a BIM model is equally trustworthy at every stage of a project, and the LOD scale is what communicates that difference precisely: a team coordinating around a model needs to know whether a given element reflects a rough placeholder or verified as-built detail before relying on it for a decision.
On a real project
Early in design, a mechanical system appears in the BIM model at LOD 200, a rough approximate shape and size, and is progressively refined until it reaches LOD 400 for fabrication-level detail and finally LOD 500, reflecting the system's actual as-built condition once construction is complete.
Who this matters most to
A BIM/VDC Specialist tracks and communicates the LOD of different model elements throughout a project, since relying on an element before it's reached the appropriate LOD for that decision can lead a team astray.
Where this goes wrong
A trade contractor pulls exact dimensions from a model element that's still only at LOD 200, a rough placeholder shape, and fabricates components based on it as if it were final. The real dimensions change as the model develops further, and the fabricated components no longer fit correctly.