In the world of Building Information Modeling (BIM), LOD stands for the Level of Development. As the required LOD can have a major impact on the size of your model, it’s useful to make a distinction between LOI and LOG.

The Level of Development can best be understood as a reference to the reliability of your model. It’s the degree to which an element’s geometry and attached (non-graphic) information have been thought through. In order to explain how this works, we’ll use a piece of fruit:

LOD = LOG + LOI

For this simplified representation of LOD = LOG + LOI, we have chosen a kiwi that is divided into the LOG (Level of Geometry) and LOI (Level of Information).

LOG: Level of Geometry

The outside, the visible part of the LOD-kiwi, is the Level of Geometry (also called level of detail). It tells us something about the appearance (the geometry) of the element.

The LOG in a BIM model expresses the geometric level of detail. For example, EMCS 4.0 distinguishes between 5 different levels, where LOG 1 stands for a schematic or symbolic representation of a product, and LOG 5 for a detailed, manufacturer-specific representation.

LOI: Level of Information

The invisible, non-geometric part of the kiwi is the LOI or Level of Information. In the example of the LOD kiwi, this is the taste, the color, the smell, the price, and the expiry date.

In BIM models, the LOI stands for the non-geometric, technical information of a model. Content with a high LOI, for example, contains manufacturer-specific information such as price and stock information.  

Get lean with LOD

Normally, the detail level of the geometry and the level of information both increase as a project progresses. However, there can be large differences between the LOI and the LOG: A component can have a symbolic representation, while the information is fully specified including manufacturer specific properties.

Differentiating between LOI and LOG is useful for managing expectations and making agreements, which benefits both the efficiency and communication within BIM projects.

Would you like to learn more about LOD and how to deal with it efficiently? Find out how the different LOD levels impact your building model.