LOD Basics
The following post is meant to be a quick high-level introduction to LOD.
LOD is an acronym used in the Building Information Modeling (BIM) context that stands for Level of Development.
LOD is a metric for gauging the completeness, precision, reliability and thoughtfulness of a model in terms of:
Site Location, Massing, Orientation and Geospatial Accuracy
Geometric Detail of the Building, Elements and Systems
Geometric Precision of the Building, Elements and Systems
Quantitative Accuracy of Building Elements
Data Associated with, Embedded in, and Derived from the Model and it’s Elements
There are 6 LOD classifications according to the progression of the model:
LOD 100 - “conceptual design”: Generic 2D or mass elements indicating an element occurs but no specifics are provided defining the element
LOD 200 - “schematic design”: Approximate size and location of elements
LOD 300 - “modeled as design-specified”: Specific size, shape, location and number of elements
LOD 350 - “modeled as actual size”: Additional precision and information about the element’s connection to other elements
LOD 400 - “supplementary components added”: Fabrication-ready detail and information
LOD 500 - “final design”: As-built information of installed elements
There are specifications that show how the different stages of LOD are reached for different types of building elements. A great resource is the BIM Forum Level of Development (LOD) Specification.
Look for more posts coming soon digging deeper into the LOD topic.
Thanks to the resources below. The quoted LOD descriptors are from reference 1 below.
References:
https://www.designingbuildings.co.uk/wiki/Level_of_Development_LOD
BIM Forum Level of Development (LOD) Specification 2020