The acronym “LOD” can be used for both Level of Detail and Level of Development. Nevertheless “Level of Detail” refers to the graphical representation of an object while “Level of Development” refers both to the graphical representation and to the information (properties) of the object.
Level of Detail:
Level of detail rises from symbolic modeling (cubes) to an extremely accurate level of detail (identical to reality, up to the electrical socket or door handle at actual dimensions):
LOD 100: Models are designed in a symbolic and generic way. Elements are not fully detailed and may come from other models of the same type.
LOD 200: Models are graphically modeled. (+) Models are modeled in a simplified way and are recognizable as an object or assembly. Quantities, shapes, quotations positions and orientations may differ from reality.
LOD 300: Models are realistically plotted as object or assembly. (+) Quantities, shapes, quotations positions and orientations are accurate.
LOD 350: Model are realistically plotted as object or assembly. Quantities, shapes, quotations positions and orientations are accurate. (+) Frameworks (interactions) are taken into account and must work in the case of calculations and simulations (structure, thermic, ...)
LOD 400: Model are realistically plotted as object or assembly. Quantities, shapes, quotations positions and orientations are accurate. Frameworks (interactions) are taken into account and must work in the case of calculations and simulations (structural, thermal, ...). (+) Datas (the “I” of BIM) must be filled in (materials, manufacturer, date of installation, maintenance, ...).
LOD 500: Model are realistically plotted as object or assembly. Quantities, shapes, quotations positions and orientations are accurate. Frameworks (interactions) are taken into account and must work in the case of calculations and simulations (structural, thermal, ...). Datas must be filled in (materials, manufacturer, date of installation, maintenance, ...) (+) Models are similar to the reality, designed in an extremely precise way and verified on site.
Level of Development:
The “Level of Development (LOD) Specification” is a reference that enables professionals in the AEC Industry to develop reliable and understandable Building Information Models (BIMs) at different lifecycle of their project.
The American Institute of Architects (AIA) has developed a model of progression specification.
This protocol determines:
- what a model can be used for
- what you can trust the model for
- what type of information can be derived from each progression
Here is the definition for the AIA E202-2008/G202-2013 BIM Protocols:
LOD 100: Essentially the equivalent of conceptual design, the model would consist of overall building massing and the downstream users are authorized to perform whole building types of analysis (volume, building orientation, cost per square foot, etc.)
LOD 200: Similar to schematic design or design development, the model would consist of "generalized systems or assemblies with approximate quantities, size, shape, location and orientation." Authorized uses would include "analysis of selected systems by application of generalized performance criteria."
LOD 300: Models are suitable for the generation of traditional construction documents and shop drawings. As such, analysis and simulation is authorized for detailed elements and systems.
LOD 400: This Level of Development is considered to be suitable for fabrication and assembly. The MEA for this LOD is most likely to be the trade contractor or fabricator as it is usually outside the scope of the architect's or engineer's services or would constitute severe risk exposure if such parties are not adequately insured.
LOD 500: The final Level of Development represents the project as it has been constructed - the as-built conditions. The model is suitable for maintenance and operations of the facility.
(source : https://www.aia.org/)
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