In this module, we’ll explore Level of Development (LOD) specification, the characteristics of the LOD definitions, and what each one means for a BIM project. Let’s get started.

When it comes to BIM, there are many terms to understand. One of them is Level of Development. Although a common term within the industry, there is still some confusion about what LOD is. Let’s take a closer look at what it means.

LOD specification is a reference that allows stakeholders to clearly define the content and reliability of BIM throughout the design and construction processes.

Interpreting LOD correctly is a challenge within the industry. It is sometimes incorrectly interpreted as Level of Detail, which refers to the amount of visual detail included in an object. Whereas Level of Development highlights the extent to which an object’s geometry and attached information has been considered and developed.

There are six definitions of LOD that illustrate the characteristics of model elements. In each definition, the level of articulation differs, allowing stakeholders to define what their systems can be used for, while providing a better understanding of the functions and reliability of the product.

Let’s take a closer look at these definitions using Grundfos MAGNA3 as an example. LOD 100.

This is the most basic definition often used in the early stages of a project. The object is represented with a symbol or basic shape, and the information is sparse. For a MAGNA3, the information would read ‘Pump 0.5 kW’. Information from LOD 100 elements should be considered a first step in the project.

LOD 200. Here, the information describing the object becomes more specific but still doesn’t correspond to the final solution. At LOD 200, a MAGNA3 would read ‘Circulator pump 0.5 kW’. Although the object is more detailed, the project is still in its early stages.

LOD 300. At this stage, the object is represented as a specific system, so features such as size, shape, and orientation can be measured directly from the model. It is specified that a MAGNA3 is being used rather than just a circulator pump, providing a detailed representation without being fully final.

LOD 350. Together with LOD 300, LOD 350 provides an accurate representation of the final product. A specific product number is added along with electrical and mechanical data.

LOD 400. Similar to LOD 350, LOD 400 adds further information. Quantity, size, shape, location, and orientation can all be measured directly from the model. At this stage, the MAGNA3 includes all delivered data, not just electrical and mechanical information. Some of this data may be added by other stakeholders, such as contractors.

LOD 500. Also referred to as an as-built model, LOD 500 is a fully verified object containing all the information needed throughout the project’s lifecycle. This includes exact location, warranty, associated parts, and service information.

Now, let’s look at the three types of rendition levels in Autodesk Revit.

The three rendition levels are coarse, medium, and fine. Although they differ visually, they contain the same data. This allows stakeholders to work in the model environment that suits them best. For example, if someone prefers working on a model in a blocky environment, the coarse rendition should be used, while the fine rendition provides greater visual detail.

While all the data is available in each LOD definition, the information required varies depending on the stakeholder’s role, such as a system designer, contractor, or operator. This makes it important to specify who needs which information throughout the project lifecycle.

Let’s recap:

•LOD specification lets stakeholders define the content and reliability of BIM during design and construction.

•LOD is about information, not just visual representation.

•Different rendition levels allow stakeholders to work in the environment of their choice; changing the rendition level does not require changing the LOD.

•The LOD definitions define and illustrate the characteristics of model elements, helping stakeholders understand the functions, reliability, and intended use of objects.

That covers our overview of LOD specification, the characteristics of the LOD definitions, and what each one means for a BIM project.