“What LOD should we model this at?” is a routine BIM question — yet the term is used surprisingly loosely. Is it about how detailed the shape is? How much information there is? This article sorts LOD out.
- LOD measures how developed a model element is
- It has two meanings: "Detail" (geometric refinement) and "Development" (information reliability)
- Expressed in stages like LOD 100–500, rising as the project progresses
- "Higher is better" is wrong — the rule is only as much as you need, where you need it
The two meanings of LOD
The acronym often carries two distinct meanings. Separating them clears up most of the confusion.
Geometric refinement
- How detailed the geometry is
- The refinement of "appearance"
Information reliability
- How far the shape + properties are fixed and trustworthy
- Maturity of information you can decide on
The crucial lens is Development (reliability). A pretty 3D (high Detail) with placeholder dimensions or properties can’t justify a purchase order. LOD expresses not just “how fine it looks” but “how far you can trust this information.”
The stages (100–500)
A common framework grades element maturity in stages (exact definitions vary by standard and practice):
LOD 100
Conceptual — approximate volume and location only.
LOD 200
Approximate — rough shape, size and properties.
LOD 300
Detailed — definite shape, size and properties; a design basis.
LOD 350
Connections — interfaces and clashes with other elements.
LOD 400
Fabrication — usable for construction and fabrication.
LOD 500
As-built — a record reflecting actual conditions.
Higher numbers mean “more refined and definite” — but also more cost and effort.
Mapping to project phases
LOD rises as the project advances.
LOD 100–200
Volume studies and rough exploration. Detail not needed.
LOD 300–350
Definite dimensions and properties; coordinated interfaces.
LOD 400
Detail that holds up for fabrication and construction.
LOD 500
Used as an as-built record.
Common misconceptions
"Higher LOD is better." Wrong. High LOD costs time and money. Modeling every element at LOD 400 during schematic design is hugely wasteful. The right move is to raise only what you need, as much as you need, for the purpose.
"LOD = geometric detail only." Incomplete. Detailed shape with empty properties is still low in information reliability (Development). Remember that the essence of BIM is information.
Summary
- LOD measures how developed a model element is.
- It carries two meanings: Detail (geometric refinement) and Development (information reliability).
- Staged as LOD 100–500, rising through project phases.
- Don’t max out everything — raise it only as much as the purpose requires.
Read LOD as “how trustworthy is this information,” not “how fine does it look,” and you avoid over-modeling while still securing the quality you need.