Level of Development

Level of development (LOD) is a set of specifications that gives professionals in the building industry the power to document, articulate, and specify the content of BIM effectively and clearly. Serving as an industry standard, LOD helps define the development stages of different systems in BIM. By using LOD specifications, architects, engineers, and other professionals can clearly communicate with each other for faster execution.

It's very important to recognize that LOD is just one parameter with which to define your Scope of Work. Other important considerations include what Views are necessary for your project's needs, what Elements do you need to see in those Views, and at what Resolution should those Elements be drafted.

For instance, our models at Existing Conditions are typically LOD 300, meaning that the Model Element is graphically represented within the Model as a specific system, object, or assembly in terms of quantity, size, shape, location, and orientation. However, no non-graphic information is attached to the model such as fabrication, detailing information, type or function. For most of our clients, this is more than enough information for their needs. And for those that need more detail, it's simply a matter of letting our team know early, in order to ensure that our work meets your expectations.

LOD was first introduced by the American Institute of Architects (AIA) in 2008 when it defined five different levels of development to define the detailing requirements of a BIM model. Level of Development (LOD) specifications are one method of allowing professionals in the industry to articulate how an element’s geometry and associated information has evolved throughout the entire process. It signifies the degree to which different members of the team can rely on information associated with an element. LOD helps to define how the 3D geometry of the building model can achieve different levels of refinement. LOD is also used as a measure of the level of service required – it requires less labor to produce a rudimentary model at LOD 100 versus a more detailed LOD 300 model. 

According to the AIA, LOD outlines the design requirements at each stage. At LOD 100, which is the pre-design stage, the model consists of 2D symbols and 3D masses to signify an element’s existence. At LOD 200, the elements are partially defined by outlining their approximate quantity, size, shape, and location. By LOD 300, the elements are defined with exact dimensions and their relative positioning. LOD 350 describes the information about an element precisely and outlines an element’s relation and connection with other components.  The LOD 400 level outlines the basic information about the construction of various elements. By LOD 500, the model begins representing the real-life functions of elements in a real building.


Here are all the LOD levels of development with their definitions:

LOD 100 - Concept Design
The 3D model is developed to represent building information on basic level. Conceptual design is suitable for this LOD stage. Parameters like area, height, volume, location and orientation are defined.

LOD 200 - Schematic Design
A general model includes elements modeled with approximate quantities, size, shape, location and orientation. We can also attach non-geometric information to the model elements.

LOD 300 - Detailed Design
The model elements are graphically represented within the model as specific systems, objects or assemblies in terms of quantity, size, shape, location, and orientation. Non-graphic information may also be attached to the model elements.

LOD 350 - Construction Documentation
This LOD includes model detail and elements that represent how building elements interface with various building systems and other building elements, partially through graphics and written definitions.

LOD 400 - Fabrication & Assembly
The model elements are created as specific assemblies, with complete fabrication, assembly, and detailing information in addition to precise quantity, size, shape, location and orientation. 

LOD 500 - As-Built
Elements are modeled as constructed assemblies for maintenance and operations. In addition to accurate size, shape, location, quantity, and orientation, non-geometric information is attached to modeled elements, such as the estimated cost of replacing a particular building element.