Level of Development (LOD)
|Out of scope This page is an introduction to the topic with links to further reading. A comprehensive article is outside the scope of the Open Source Architecture project.|
The Level of Development in a BIM specifies what data must be in the model at what stage in the project development. The main specification is the American BIMforum document Level of Development (LOD) Specification parts I and II. A good introduction is a 2014 presentation from the American Institute of Architects called What is this things called LOD?
Unfortunately there are multiple definitions of the abbreviation LOD refering variously to Level of Detail, Level of Design and Level of Development. What is important is that they all refer to what must be delivered and when.
With the introduction of ISO19650 the International Standard Organisation has renamed and redefined some of these terms based on the former British standard series PAS 1192.
United States of America
The main specification is the American BIMforum document Level of Development (LOD) Specification parts I and II. This is also regarded by many as the defining international standard.
There is a Danish specification (available in English) developed by Digital Konvergens (DiKon) and BIM7AA called The Specification of Building Parts. The Danish specification breaks the Level of Development down into three components: Level of Reliability (LOR), Level og Geometry (LOG), Level of Information (LOI). This allows for the specification of a detailed model with little data (perhaps for rendering), or an information rich model with basic geometry (perhaps for facility management).