AIA LOD Descriptions

The AIA has come up with the following LODs in regards to a projects lifecycle from design to as-built and maintenance drawings.

LEVEL of DEVELOPMENT DEFINITIONS PER PHASE AIA Level of Development (LOD) Definitions are as follows (also refer to the referenced AGC LOD Document): LOD 100 – Compatible with Conceptual/Schematic Design Phase The Model Element may be graphically represented in the Model with a symbol or other generic representation but does not satisfy the requirements for LOD 200. Information related to the Model Element (i.e. cost per square foot, tonnage of HVAC, etc.) can be derived from other Model Elements.

BIMForum Interpretation: LOD 100 elements are not geometric representations. Examples are information attached to other model elements or symbols showing the existence of a component but not its shape, size, or precise location. Any information derived from LOD 100 elements must be considered approximate.

LOD 200 – Compatible with Design Development Phase The Model Element is graphically represented within the Model as a generic system, object, or assembly with approximate quantities, size, shape, location, and orientation. Non-graphic information may also be attached to the Model Element.

BIMForum interpretation: At this LOD elements are generic placeholders. They may be recognizable as the components they represent, or they may be volumes for space reservation. Any information derived from LOD 200 elements must be considered approximate.

LOD 300 – Compatible with Construction Document Phase The Model Element is graphically represented within the Model as a specific system, object, or assembly in terms of quantity, size, shape, location, and orientation. Non-graphic information may also be attached to the Model Element.

BIMForum interpretation: The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension callouts.

The project origin is defined and the element is located accurately with respect to the project origin.

LOD 350 – Compatible with Construction Document/Bidding/Procurement Phase The Model Element is graphically represented within the Model as a specific system, object, or assembly in terms of quantity, size, shape, location, orientation, and interfaces with other building systems. Non-graphic information may also be attached to the Model Element.

BIMForum interpretation: Parts necessary for coordination of the element with nearby or attached elements are modeled. These parts will include such items as supports and connections. The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension callouts.

LOD 400 – Compatible with Construction Coordination/Fabrication Phase The Model Element is graphically represented within the Model as a specific system, object, or assembly in terms of size, shape, location, quantity, and orientation with detailing, fabrication, assembly, and installation information. Non-graphic information may also be attached to the Model Element.

BIMForum interpretation: An LOD 400 element is modeled at sufficient detail and accuracy for fabrication of the represented component. The quantity, size, shape, location, and orientation of the element as designed can be measured directly from the model without referring to non-modeled information such as notes or dimension callouts.

LOD 500 – Compatible with Record Models, As-Built Models for Closeout/Handover Phase BIMForum interpretation: Since LOD 500 relates to field verification and is not an indication of progression to a higher level of model element geometry or non-graphic information, the BIMForum LOD Specification does not define or illustrate it. The below definition of LOD 500 is specific to McCarthy’s expectations after 100% Construction Documents and post-Trade Coordination sign-off for model maintenance: 1). LOD 500A relative to Maintaining Record Design-Intent Models: Representative of the Record Design-Intent Models being maintained with any official changes to the Work, through Substantial Completion. Field Verification of the Record Design-Intent is not a direct requirement of the Design Team’s Record models. LOD 500A is typically the responsibility of the Engineer of Record (DOR) for that designated scope of work per the LOD Matrix of BIM Deliverables.

2). LOD 500B relative to Maintaining As-Coordinated Models: Representative of the As-Coordinated Trade Contractor models being maintained, inclusive of any official changes to the Work, through Substantial Completion. Trade Contractors are to ensure any postsignoff model/drawing changes do not impact other Trade Contractors respective to their Work. LOD 500B is typically the responsibility of the Trade Contractor for that designated scope of work per the LOD Matrix of BIM Deliverables.

3). LOD 500C relative to As-Built Models/Field Verification: Representative of the As-Built Trade Contractor models matching final construction conditions, inclusive of any official changes to the Work, through Substantial Completion. Field Verification of the Trade Contractor’s model and drawing files aligning to produce their final As-Builts. LOD 500C is typically the responsibility of the Trade Contractor for that designated scope of work per the LOD Matrix of BIM Deliverables.