So What is an LOD Anyway?

By James Germano, Esq., Manager & Counsel, AIA Contract Documents

January 14, 2022

Long gone are the days of pencils, erasers, mylar, rulers, compasses, and T-squares. Most construction projects these days are designed digitally, through a process known as Building Information Modeling, or “BIM”. When using BIM, it is important to have a very clear set of rules in place so everyone on the project knows what the Model, and the “Model Elements” in a Model (such as an HVAC unit, a wall, an elevator, a door, a window, etc.), are meant to convey. This is where LODs come in.

LOD stands for “Level of Development.” LODs range from LOD 100 to LOD 500, with LOD 100 being less developed and LOD 500 being more developed. The Level of Development (LOD) framework allows the Project Participants to understand the progression of a Model Element from conceptual idea to precise definition and description. The LOD of a given Model Element informs the other Project Participants about how developed the information is expected to be, and the extent to which that information can be relied upon, at a particular point in time in the development of the Model. Identifying the LOD for each Model Element, along its development path, helps prevents other Project Participants from using the Model Element in an unintended manner or inferring greater precision than the Model Element Author intends.

You might be thinking “Can’t I just tell how developed a Model Element is by looking at it?” Not always! This is why LODs are an incredibly important aspect of a Model. Since many different Project Participants can have access to a Model, LODs are the way by which the person Modeling (the “Model Author”) tells everyone how much they can rely upon their Model Elements. By way of example, think of a door. When you zoom into the Model, this Model Element might look very developed – the Model Author included hinges, a handle, a deadbolt, and a color. But – and here’s the important part – when it comes time to place an order with the door manufacturer, how will you know whether all these components should be included in your order, or if they’re just generic placeholders? An LOD gives you your answer. In this way, two Model Elements might look identical, but you can extract much different information when you include the LOD. LODs should be defined in your contract, so consult your contract to determine how your LODs are defined and how they are intended to be used on your project.

You can read more about the AIA’s Digital Practice Documents, including a deep dive into LODs, in the Guide, Instructions, and Commentary.

AIA Contract Documents has provided this article for general informational purposes only. The information provided is not legal opinion or legal advice and does not create an attorney-client relationship of any kind. This article is also not intended to provide guidance as to how project parties should interpret their specific contracts or resolve contract disputes, as those decisions will need to be made in consultation with legal counsel, insurance counsel, and other professionals, and based upon a multitude of factors.