LOD (level of detail) stands for the level of detail of a 3D model, it is applied to the geometrical detailing of 3D models, mainly buildings.
LOD0 is the lowest level of detail. It represents the area (footprint) of the building and sometimes also the roof edge polygons, marking the transition from 2D to 3D GIS.
LOD1 is a common mass or block model for buildings with flat roof structures. It shows the 2D outline of the building with minimum, maximum or average height. LOD1 is a coarse prismatic model usually obtained by extruding the LOD0 model upwards.
LOD2 is a slightly more complex model with a simplified roof shape, where parts of the object are modelled in several semantic classes (for example, roof, wall). LOD2 is used for urban areas and projects.
LOD3 is an architecturally detailed 3D model which is significantly more complex than previous models. This model shows in detail wall and roof structures with windows, doors, and contains facade details.
The LOD4 model complements LOD3 by including indoor representation. This model shows in detail the interior and exterior structures of buildings, such as stairs, doors, furniture, etc.
