Level of Development (LOD)

Documentation for this support article is from Project Collaboration: How to Use Assemble to Track Level of Development to Deliver on your BIM Execution Plan, a whitepaper provided by Jim Bedrick, FAIA, LEED AP and Nancy Clark Brown, AIA. To view the whitepaper in its entirety, click here.

Level of Development is a language for describing and assessing model component development over the course of the project. A numerical value is used to describe the amount and reliability of information provided by that object or required of the Model Element Author (MEA) at a particular point in time.

What is the Role of the Architect and Engineer in model LOD?

Architects and engineers manage and author the greatest amount of modeling information. They are largely responsible for communicating to the project team the LOD that can be achieved at the various milestones in the development of the MDS Matrix. They are also responsible for assigning an LOD to particular components and systems in the model and keeping the team updated on a regular basis.

The following workflow illustrates how to create and track Current LOD against the Required LOD using Revit and Assemble.

1.  Choose Import from the Project Settings screen to upload an Excel spreadsheet with the Required LOD specified for a given milestone into the Assemble Project Settings.

To learn for about creating your own Custom Assembly Codes, Costs, and Level of Development file, click here.


2.  Set up a Current LOD project parameter in Revit. From the Manage tab, select Project Parameter and create a Current LOD parameter as shown.


3.  Identify the Current LOD for each component type in the Revit model, by selecting all the instances and entering the Current LOD in the Properties window.


 4.  From the Assemble tab, select Publish and name the model version. Then choose Continue.

To learn more about Publishing Your Model to Assemble, click here.


5.  Open the model in Assemble to review and track model development for the Current LOD vs. the Required LOD.

To learn more about Working with Columns or Working with Views, click here.


What is the Role of the Contractor in Model LOD?

Contractors and/or their subs may be responsible for authoring constructability and fabrication level of development in a model depending on the scope of work. They will also use the model information at agreed milestones for creating, for example, different types of cost models; conceptual at first and then working toward a more detailed estimate. The LOD for model components can be used to communicate the parts of a project that are ready for conceptual or material level estimating based on the execution plan. Contractors will also track variances in models between milestones (or more frequently if possible), to track budget items, scope and to identify changes that need to be made to estimates.

The following workflow illustrates how to review the Current LOD, identify scope changes and adjust construction budget accordingly within the Assemble Platform.

1.  Open the Required LOD view to understand Current LOD model development. Validate objects are ready for conceptual estimating purpose by Filtering for LOD 250 or greater.

To learn more about Working with Views or Working with Filters, click here.


2.  Compare your model versions by running a Variance Report in Assemble between the new model version and a previous model version to track model, scope, and assembly changes.

To learn more about Comparing Model Versions, click here.


3.  Update budget items or conceptual estimate based on model changes by select the (dollar sign) icon. Select Fill in Gaps to fill in unit costs for new model components automatically.

To learn more about Automated Estimating, click here.


What is the Role of the Owner in Model LOD?

The Owner will be responsible for signing off on the model at the milestones identified in the BIM Execution Plan. Setting expectations for how the model will be used and what LODs are required for hand-off are critical for project success. Owners can use Assemble to quickly create schedules and views of project information to visually validate whether the model meets milestone criteria.

The following workflow illustrates how to review the LOD for the current project milestone and check the model information for required attributes.

1.  Open the Required LOD view to understand Current LOD model development. Validate model components meet milestone criteria.


2.  Check model for required project attributes for particular milestones. In the case below, a door schedule is created by room to verify doors associated with a particular room and its attributes.

To learn more about Organizing the Model Data, click here.


Managing Level of Development for a building information model enables collaboration around a model, accelerates communication and improves overall efficiency and delivery of the modeling process. For more detail on the Model Development Specification process and LOD, please review The Model Development Specification by James Bedrick, FAIA, LEED AP.

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