In BIM, the way we measure the amount and type of information in a model has traditionally been through LOD (Level of Detail or Development). The ISO 19650 standard introduced LOIN (Level of Information Need).
Both serve the same purpose: making sure we all agree on how much detail and what kind of information should be in the model at a given stage.
LOD: The Old Scale
LOD is often shown as a scale from LOD 100 to LOD 500:
- LOD 100–200: Rough massing, concept-level geometry.
- LOD 300: Accurate geometry that can be coordinated across trades.
- LOD 400: Fabrication-level detail.
- LOD 500: As-built record of what was installed.
The problem is that this scale can be too rigid. One trade may only need basic geometry at a stage, while another may need detailed data. Saying “everything must be LOD 300” doesn’t always reflect reality.
LOIN: The ISO 19650 Approach
LOIN is more flexible. Instead of numbers, it asks:
- What geometry is needed?
- What alphanumeric data is needed?
- What documents or links are needed?
- By when, and for what purpose?
Soinstead of saying “this door is LOD 300”, we can say: “At design stage, this door must have correct dimensions, fire rating, and swing direction. At construction stage, we add manufacturer and hardware details.”
Applying LOD/LOIN to the “Less but More Accurate” Approach
Here’s how the standards tie into the idea:
At design stage: We aim for lower LOD but higher accuracy. For example, walls and equipment may only be simple shapes, but their locations and sizes are exact. This aligns with LOIN because it defines precisely what data is critical at this stage, without forcing every element to be over-detailed.
Image 1: Snapshot of a generic geometry 3D model with relevant data as correct thickness in wall assemblies and wall type tag.
At construction stage: Trades enrich the model with higher LOD/LOIN. They add fabrication details, manufacturer specs, and installation info, because that’s when the project needs it.
At handover: The model reaches required LOD/LOIN, giving the owner accurate as-built information for operations.
Image 2: Snapshot of a detailed 3D model showing precise dimensions, constructability and relevant data attach to geometry, such as guarantee, manuals, etc.
The Consultant’s Role
By structuring projects around LOD/LOIN deliverables, we:
- Give design consultants confidence that they only need to model what they can stand behind, without disclaimers.
- Allow contractors to take that accurate base and add the detail they need for fabrication and installation.
- Ensure owners receive a reliable digital twin that matches reality.
This balance, less but accurate in design, more detail added in construction, is exactly what LOD and LOIN are meant to support.
Curious to dive deeper into BIM practices? Check out our related blog posts for more insights and strategies to elevate your projects!
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