What is Level of Detail (LOD)?
Level of Detail (LOD) is a crucial framework for defining the richness, reliability, and accuracy of a 3D model. In the geospatial and construction industries, LOD is not just a measure of visual detail; it's a standard that defines the content requirements and geometric precision of building information models (BIMs) at different stages of a project.
By clearly defining the LOD for a given deliverable, we ensure that every member of the design and build team is working from a shared, consistent understanding of the data's level of completeness. This prevents miscommunication, reduces errors, and streamlines the workflow.
LOD is a nationally recognized standard, primarily through NBIMS-US (National Building Information Modeling Standard-United States) and internationally through ISO 19650. These standards provide a consistent framework for everyone involved in a project, from the initial scan to the final construction and operation.
Here is a breakdown of the generally accepted LOD number ranges:
LOD 100
At this level, the model's elements are represented graphically with a symbol or other generic representation. The information is not based on precise quantities, size, shape, location, or orientation. Think of it as a basic block diagram or a massing model. It's used for early-stage planning and conceptual design.
LOD 200
Approximate Geometry: The model's elements are represented with approximate size, shape, location, and orientation. Non-geometric information can be attached to the model elements. This is suitable for general design and schematic planning.
LOD 300
Precise Geometry: The model's elements are represented with accurate size, shape, location, and orientation. This level of detail allows for accurate construction-level documentation and coordination. It's used for detailed design, engineering, and clash detection.
LOD 400
Fabrication and Assembly: The model's elements are represented with sufficient detail and accuracy to support fabrication and assembly. This includes specific part information, connections, and construction details. This is the level required for pre-fabrication and modular construction.
LOD 500
As-Built and Operations: The model's elements are represented as a high-fidelity digital twin of the actual field conditions. It is used for facility management, maintenance, and operations. At this level, the model's information is a verified, real-world representation of the completed project.