What are BIM Levels of Development (LOD)?

LOD (Level of Development) is a reference tool developed to improve communication between BIM users who exchange information through models and to ensure consistency in application.

The concept of LOD (Level of Development) was developed by Weber and Vico in 2005. It was created in order to define a model level and to get output for the possible application method, and different versions were developed over time.

LOD (Level of Development) has been developed to prevent some problems that may arise in projects working with the BIM system and to specify the level of the BIM model according to the project content.

The Building Information Model Protocol Form is the most recent published form containing definitions of a standardized responsibility matrix and basic LOD (Level of Development). Other forms developed after this form refer to the LOD (Level of Development) definitions developed for the “Building Information Model Protocol Form” by the AIA, known as the American Institute of Architects.

BIM Maturity Levels

The Bew-Richards diagram was developed by Mark Bew and Mervyn Richards in 2008. In this diagram, they divided the process and data management systems into four stages in the BIM system and showed them as Level 0, Level 1, Level 2, Level 3.

If we explain these stages shown above.

Level 0: It is the stage where most of the design process takes place and 2D CAD files are used.

Level 1: It is the stage where 2D CAD drawings created at Level 0 are passed to 3D CAD drawings. Electronic data sharing is achieved through a common data medium by specifying CAD standards.

Level 2: It is a stage where interdisciplinary work can be done and it is possible to work together. Project stakeholders can produce their own 3D models and add them to the common data platform. 4D program planning and 5D cost management within the BIM system can be used at this level.

Level 3: It is the stage where the BIM discipline can be fully implemented. It is the most suitable stage for interdisciplinary and simultaneous work. It is managed in accordance with IFC (Industry Foundation Classes) and IFD (International Framework for Dictionaries) standards. At this stage, the cost estimation process is accelerated. Occupational safety analysis to be used in the construction of the building and facility management is made. Finally, the future situation can be determined by value engineering analysis.

LOD (Level of Development) Levels

Projects created with the BIM system may contain unnecessary information for people who want to have information about the project, other than designers. Thus, wrong inferences can be made about the project. Vico Software Inc has made a study to avoid misunderstandings. In this study, LOD levels are defined based on design elements. If we explain these LOD levels developed to improve the quality of communication between BIM users;

LOD 100: Indicates the preliminary design phase. The model element can be represented as a symbol or graphic.

LOD 200: Expresses the systematic design phase. In this phase, where building elements and non-geometric data are associated with each other, information such as size, shape and location are specified in a way close to the application.

LOD 300: It is the design development phase. Information such as the size, shape, position, direction and quantity of the model element in the design are directly displayed in the model graphically.

LOD 400: It is the construction phase phase. In the model, the size, shape, position and direction of the element are specified in detail, including production, assembly and installation information.

LOD 500: Facility management phase. The model object is considered a field-validated representation in terms of quantity, direction, shape, size, and location.

LOD levels are visually represented below.

LOD 200 level is the lowest accepted level in projects created with BIM system.