At the Spring BIMForum in Boston James Vandezande and Will Ikerd gave an update on the status of the BIMForum's Level of Development (LoD) specification. The Level of Development (LOD) Specification is a reference that enables practitioners in the AEC Industry to specify with a high level of clarity the content and reliability of Building Information Models (BIMs) at various stages in the design and construction process. It allows model authors to define what their models can be relied on for, and allows downstream users to clearly understand the usability and the limitations of models they are receiving. The specificaton does not prescribe what Levels of Development are reached at what point in a project. Its primary objectives are;
- To help teams, including owners, to get a clear picture of what will be included in a BIM deliverable
- To help design managers communicate the level of detail that needs to be provided at various points in the design process
- To provide a standard that can be referenced by contracts and BIM execution plans.
Version 1 of the specification which was released in 2013 includes LOD levels
- LOD 100 - A model element may be graphically represented in the model with a symbol or other generic representation.
- LOD 200 - A model element is graphically represented as a generic object with approximate quantities, size, shape, location, and orientation.
- LOD 300 - A model element is graphically represented as a specific object with quantity, size, shape, location, and orientation.
- LOD 400 - A model element is graphically represented as a specific object with size, shape, location, quantity, and orientation and with detailing, fabrication, assembly, and installation information.
The specification has been accepted into the National BIM Standard (NBIMS) and a number of major organizations have adopted and are using it including the U.S. Army Corps of Engineers, Mayo Clinic, and Massport.
Additions to be expected in the future include
- LOD 350 - A model element is graphically represented as a specific object with quantity, size, shape, orientation, and interfaces with other building systems.
- LOD 500 - A model element is a field verified representation in terms of size, shape, location, quantity, and orientation.