BIM Level of Detail (LOD)
Defined for every BIM model at the quotation stage
When creating scan to BIM models of existing buildings, it’s important to remember that BIM software such as Revit, ArchiCAD or AECOsim was designed for new construction. Existing buildings are recorded with 3D laser scanning, which is very accurate and detailed, but converting a point cloud into a BIM model takes considerable effort and is often limited by the software itself. That’s why the level of detail (LOD) and the expected accuracy need to be agreed before modelling starts.
The levels below are a simplified classification that helps us agree the scope with you and understand how the model will be used. Treat them as a guide, not a rigid rule
For example, a model can be delivered at LOD 2 with selected elements, such as windows or doors, added on request. The level of detail can also vary across the building: high on a retained façade, low on internal partitions that will be removed.
The level of detail directly affects modelling time and the project budget, so at the quotation stage we aim to agree it as precisely as possible. At each stage of modelling, and once the model is complete, we carry out a Model Quality Check. Below the levels you’ll find a form where you can specify exactly which elements need to be modelled.
Level 1 – Mass Model
Modelling at Level of Detail 1 is generally used to show the architectural context of a new development. Solid models of surrounding buildings make it possible, for example, to analyse sunlight exposure.
the least detailed and most general BIM model
shows the general form of the building
windows, doorways, services and architectural details are not modelled
Level 2 – Basic Structural model
Modelling at Level of Detail 2 is used as a base for the preliminary architectural concept. An LOD 2 BIM model provides detail equivalent to 2D documentation at a scale of 1:200.
contains the main structural elements and openings: floors, columns, beams, and door and window openings in a basic form
services, architectural details, partition walls and interior doors are not modelled
Level 3 – Basic Architectural model
Modelling at Level of Detail 3 is used as a base for design work, excluding construction documentation. An LOD 3 BIM model provides detail equivalent to 2D documentation at a scale of 1:100 or 1:50.
contains all structural elements and simplified architectural details
external doors and windows are modelled
interior walls with doors and service components are included
Level 4 – Detailed Architectural model
Modelling at Level of Detail 4 is generally used for detailed engineering design and interior finishing projects. An LOD 4 BIM model represents architectural details with the most precise geometry.
contains all structural and architectural elements in detail
even the smallest service items and furniture are modelled
external doors and windows are modelled with details such as door handles
What level of detail is produced in a scan to BIM model?
It depends on how the model will be used, and we agree it for each project. As a rule of thumb: LOD 1 for context and massing studies, LOD 2 for concept design, LOD 3 as a base for design work, and LOD 4 for detailed design and interior projects. Different elements or parts of the building can be modelled at different levels, so you only pay for the detail you need.
LOD, LOI and detail level in Revit
Level of detail (LOD) describes the geometry of the model. Level of information (LOI) describes the data attached to its elements, such as types, materials or parameters. Both are agreed at the outset, especially for existing buildings, where not every part of the structure can be accessed or verified. LOD should not be confused with the Detail Level view setting in Revit (Coarse / Medium / Fine), which only controls how elements are displayed in a view.
How our levels compare to industry standards
Our LOD 1–4 are a practical classification for quoting and broadly correspond to LOD 100–400 in the BIMForum LOD Specification. In the UK, requirements may also be defined as Level of Definition (LOD and LOI) or as Level of Information Need under ISO 19650. If your project has specific LOD requirements, or the model must meet ISO 19650 requirements, send them to us and we’ll align the deliverable.
Not sure which level you need?
More detail isn’t always better: it can multiply modelling costs without adding real value. Learn how to define the right LOD and accuracy for your project →
DOCUMENTS TO DOWNLOAD:
Level of detail for other deliverables
Need a different type of deliverable? See how we define level of detail for:
