Understanding Level of Development (LOD) in Building Information Modeling (BIM)

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

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January 14, 2022

The Evolution of Construction Design with BIM 

Gone are the days when construction projects were designed with pencils, erasers, and rulers. Today, most construction projects are created using Building Information Modeling (BIM), a digital process that revolutionizes how the industry approaches design and collaboration. However, as BIM becomes more integral to construction, the need for a clear understanding of the data and elements within a model becomes crucial. This is where Level of Development (LOD) comes in. 

 

What is Level of Development (LOD) in BIM? 

LOD, or Level of Development, refers to the degree of detail and accuracy of a BIM model element at a specific stage of a project. LODs range from LOD 100 to LOD 500, where LOD 100 represents a conceptual idea and LOD 500 signifies the most developed, as-built version of a model element. 

The LOD framework is vital for ensuring that all project participants—architects, engineers, contractors, and manufacturers—understand the degree to which they can rely on the information in the model. It guides everyone involved on how developed each element is and what level of certainty can be attached to it at different stages of the project. This system is particularly important for avoiding confusion and ensuring that the right information is conveyed at the right time. 

 

The Importance of LOD in Construction Projects 

With multiple stakeholders having access to the BIM model, clear LOD definitions help prevent misunderstandings about the level of detail and precision involved. For example, imagine looking at a BIM model of a door. The model might include hinges, handles, deadbolts, and a color. At first glance, it may seem fully detailed. However, without an LOD indicator, you won’t know whether these components are placeholders or actual specifications that need to be ordered. LOD ensures that project participants know what can and can’t be relied upon at each phase. 

 

Breakdown of LOD Levels: From LOD 100 to LOD 500 

The LOD framework allows you to track a model element from its initial concept to its final, precise definition. Here’s a breakdown of each LOD level: 

  • LOD 100: Conceptual Stage – At this early stage, the model element is simply represented as a mass or generic placeholder, with little to no specific information. 
  • LOD 200: Schematic Stage – The element begins to take shape with general specifications and approximate sizes, but it still lacks precise details. 
  • LOD 300: Detailed Design Stage – The model element is now fully defined, including exact dimensions, materials, and placement, but it may still lack some fabrication details. 
  • LOD 400: Fabrication Stage – At this stage, the element includes all the details required for fabrication, installation, and construction, including accurate component sizes, materials, and connections. 
  • LOD 500: As-Built Stage – This is the most developed level, representing the final, built version of the element, including actual as-built conditions and complete data. 

 

Why LOD is Critical for Construction Project Success 

Understanding LOD is essential for ensuring that the BIM model is used correctly throughout the project’s lifecycle. By defining LODs clearly, teams can: 

  1. Enhance Accuracy and Reliability – LOD provides clarity on what information is reliable at each stage, helping all project participants make informed decisions.
  2. Ensure Proper Coordination – With LODs in place, stakeholders can avoid misusing model elements, preventing costly mistakes or rework. 
  3. Facilitate Clear Communication – LOD helps team members communicate expectations clearly, making collaboration more efficient and minimizing confusion. 

 

How to Define and Use LODs in Your Contract 

To make the most of the LOD framework, it’s essential to define the specific LOD requirements in your contract. Clear LOD definitions ensure that everyone on the project understands what is expected and can plan accordingly. Be sure to refer to your contract to confirm how LODs are to be used and interpreted for your specific project. 

 

Mastering LODs for Better Project Collaboration 

Mastering Level of Development (LOD) is crucial for the success of any BIM-enabled construction project. It ensures that each element within the model is properly defined, understood, and used according to its level of development. By understanding and correctly applying LODs, project teams can improve communication, minimize errors, and ensure smoother project execution. 

For more in-depth information on LOD and BIM, check out the AIA’s Digital Practice Documents, including detailed guides and commentaries on how to effectively utilize LODs in your projects. 

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.