At the Fall BIMForum/BuildCon conference in Dallas, BIMForum announced the 2017 release of the 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. The 2017 specification has been released under a Creative Commons license that allows anyone to use the LOD specification non-commercially with attribution and no derivatives. In other words you can use it for free, as long as you don't sell it, that you include attribution to BIMForum and that you don't change it.
The 2017 release also includes levels and grids and five types of coordinate systems; assembly or object coordinates, local building coordinates, local campus coordinates, state plane or civil coordinates and geospatial or GIS coordinates. BIMForum is encouraging software developers to become aware of the new LOD specification in hopes that they will integrate it into design and construction software applications.
In April 2014 at the Spring BIMForum in Boston James Vandezande and Will Ikerd gave a summary of the BIMForum's recently released LoD specification. It was intended to allow authors to define what their models can be relied on for, and to allow downstream users to clearly understand the usability and the limitations of models they are receiving. The specification did not prescribe what Levels of Development are reached at what point in a project. Its primary objectives were;
- 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 included LOD levels upto 400
- 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 350 - A model element is graphically represented as a specific object with quantity, size, shape, orientation, and interfaces with other building systems.
- 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.
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