Understanding LOD

February 14, 2020
Posted in News
February 14, 2020 admin

Understanding LOD

“Level of Development” vs. “Level of Detail”

The LOD stands for “Level of Development” … Well, in most cases anyway.

Let’s start with a little bit of history and the first use of LOD: Vico Software, company that makes construction analysis software first used “Level of Detail” in their software to define reliability and suitability of the modeled elements for various stages of the design process, and nicknamed it LOD. This acronym has been used ever since, but it has been redefined to “Level of Development” to emphasize importance of non-geometric information in elements.

Each BIM element has both geometric and non-geometric information, but degree of implementation, quality and accuracy of this information varies depending on milestones and/or the stage of the project. Level of Development should be observed as a way to know how developed should elements in your BIM model be at each stage based on client needs and intent of usage for the BIM model

It is important to understand that it’s not just about the amount of information a model contains, but also the quality, usefulness and reliability of information that can be extracted.

The National BIM Standard-United States® (NBIMS-US™)

The most used way for defining LOD is with LOD numbers. There are six different main levels described: LOD100, LOD200, LOD300, LOD350, LOD400 and LOD500.

Because BIM model is developed throughout project stages but also milestones and various trades, there isn’t necessarily one LOD for the whole model. Some elements can be modeled at LOD200, while others can be modeled at LOD400 at the same stage of a project. If a model appears to have only one LOD, it usually implies that it’s architectural LOD in question.

UK BIM or …vs. “Level of Definition”

While UK BIM doesn’t defer much from original concept for “Level of Development”, it does have some differences in the approach – it actually divides LOD into two intuitive components: “Level of model detail” with focus on how complex are geometric components of a model and “Level of model information” which defines how developed are non-geometric characteristic of BIM model.
Main levels of LODs are described in table below.

Why is LOD downgrade a good thing?

There is an interesting concept being used nowadays: a LOD downgrade for FM. In theory for LOD500, you should enrich model with FM needed data, but keep the LOD400 geometry of the whole model. For practical uses, this model can be overpopulated with unnecessary data and confusing for actual manager using them. Goal is to downgrade geometry features to lowest level needed.

For more useful information on the topic, please visit:

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