Today, let’s discuss What BIM Model Accuracy Is and Its Related Standards. Building Information Modeling (BIM) involves collaboration among multiple disciplines to create detailed models. Establishing clear standards and guidelines is essential, and the Level of Development (LOD) framework provides these guidelines. Users rely on the model’s content level, ownership clarity, BIM standards, file formats, and defined responsibilities for model management throughout the project lifecycle.
Understanding BIM Model Accuracy
The Level of Development (LOD) concept was introduced by The American Institute of Architects (AIA) in the E202™ standard back in 2008. It defines various levels of detail in BIM models, serving as a tool to manage the use and legal requirements of building information models. The framework consists of five development levels, each progressively more detailed.
The accuracy of BIM models is categorized into five levels: LOD 100, LOD 200, LOD 300, LOD 400, and LOD 500. In 2013, the AIA revisited these standards and updated the definitions in E203™, G201™, and G202™ standards, improving upon the original 2008 E202™ definitions. Below is a comparison between the 2008 and 2013 standards:
Comparison of E202™ 2008 and G202™ 2013 Standards
1. Differences in LOD 100
E202™ – 2008:
Model content requires representation of the overall building volume through area, height, volume, position, and orientation. This can be achieved via 3D modeling or other data forms.
G202™ – 2013:
Model elements can be graphically displayed using standard symbols or generic representations but may not satisfy LOD 200 requirements. Information related to model elements may derive from other model elements.
2. Differences in LOD 200
E202™ – 2008:
Model elements are generalized systems or components modeled with approximate quantities, sizes, shapes, positions, and orientations. They may also include non-geometric information.
G202™ – 2013:
Model elements are graphically represented as generic systems, objects, or components with approximate quantities, sizes, shapes, positions, and orientations. Non-geometric information can also be attached.
3. Differences in LOD 300
E202™ – 2008:
Model elements have precise and specific quantities, sizes, shapes, positions, and orientations during modeling. Non-geometric information may also be included.
G202™ – 2013:
Model elements are represented graphically as specific systems, objects, or components with exact quantities, sizes, shapes, positions, and orientations. Non-geometric information can also be linked.
4. Differences in LOD 350
E202™ – 2008:
No definition provided.
G202™ – 2013:
LOD 350 includes sufficient detail for installation and interdisciplinary coordination.
5. Differences in LOD 400
E202™ – 2008:
Model elements are modeled as specific components, including accurate size, shape, position, quantity, and orientation. They contain detailed information for manufacturing and assembly. Non-geometric data may also be attached.
G202™ – 2013:
Model elements graphically represent specific systems, objects, or components with precise size, shape, position, quantity, orientation, detailed design, manufacturing, assembly, and installation information. Non-geometric information is also included.
6. Differences in LOD 500
E202™ – 2008:
Model elements reflect actual and accurate dimensions, shapes, positions, quantities, and orientations of construction components. Non-geometric information may be attached.
G202™ – 2013:
Model elements correspond to on-site conditions in size, shape, position, quantity, and orientation. Non-geometric information can also be linked to the elements.
That wraps up our overview of What BIM Model Accuracy and Related Standards entail. I hope this article helps clarify the topic for you!
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