Animation about the level of detail (LOD) concept of the OGC CityGML 2.0 standard (opengeospatial.org/standards/citygml)
The standard defines five levels of detail for multi-scale modelling. The LODs increase in their geometric and semantic richness to support a variety of applications. For buildings they are described as follows.
LOD0 is a horizontal polygon that represents the footprint and optionally the roof edge polygon of a building. LOD1 is a block model with flat roofs. A building in LOD2 is modelled with differentiated roof structures and thematically differentiated boundary surfaces. LOD3 represents architectural models with detailed wall and roof structures and it includes doors and windows. LOD4 completes a LOD3 model by adding interior structures for buildings, such as rooms and furniture.
The LOD concept of CityGML became a popular way in the industry for concisely describing the grade of a 3D city model.
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