LOD 300 and LOD 350 differ primarily in the modeling of interfaces and connections between building elements. In this article, ViBIM experts break down these two critical development levels using industry-standard definitions, provide a detailed comparison table, and share specific criteria to help you decide which LOD is right for your next project.
What is LOD 300?
According to the BIMForum Level of Development Specification, LOD 300 elements are defined as being “sufficiently developed to fully convey the design intent for the represented item”
At this level, the Model Element is graphically represented within the model as a specific system, object, or assembly such that its quantity, size, shape, location, and orientation can be measured directly. Unlike lower levels of development, LOD 300 provides precise geometry rather than generic placeholders. For example, a structural column at LOD 300 is modeled with its exact dimensions (e.g., a W12x53 steel beam) and is placed at the correct grid location.
It is important to note a key distinction regarding roles at this stage: while LOD definitions do not specify who must model the element, BIMForum documents highlight that designers rarely generate model elements higher than LOD 300. This level is typically the ceiling for design deliverables, providing enough precision for construction documentation and shop drawings without entering the realm of detailed fabrication coordination found in LOD 350.
What is LOD 350?
According to the BIMForum Level of Development Specification, LOD 350 is intended to define requirements for model elements that are “sufficiently developed to support construction-level coordination.” For renovation projects requiring this level of accuracy, understanding what is scan to bim is often essential to capture the precise reality needed for coordination.
At this level, the Model Element is graphically represented within the model as a specific system, object, or assembly such that its quantity, size, location, orientation, and interfaces with adjacent or dependent Model Elements can be measured. This specific inclusion of interfaces—how parts connect and interact—is what distinguishes it from the standalone nature of LOD 300.
The BIMForum expansion highlights that achieving this level “usually requires craft knowledge.” Because of this requirement, designers rarely generate model elements at LODs higher than 300. However, it is important to remember that the specification does not dictate who models the element; if a design team has the necessary craft knowledge available, they may choose to develop elements to LOD 350 or higher themselves.
The Key Differences: LOD 300 vs. LOD 350 in Detail
Below ViBIM provides a table outlining the differences between LOD 300 vs LOD 350:
| Criteria | LOD 300 | LOD 350 |
| Geometry & Position | Elements are precise in terms of specific system, quantity, size, shape, location, and orientation. The element acts as a standalone object without detailed interfacing geometry. | Extends LOD 300 precision by explicitly modeling the interfaces and cross-system connections. The geometry reflects the actual installation footprint, including fastening hardware. |
| Connection & Installation Info | Provides “just enough to get going.” It defines what the element is and where it is, but implies the connection rather than modeling it. Hardware like bolts, hangers, or supports are usually excluded. | Explicitly details how components connect. It includes installation-related information such as supports, hangers, base plates, and gussets required for on-site assembly and valid clash detection. |
| Purpose of Use | Suitable for producing accurate design development documents, construction drawings, and initial fabrication plans where standard installation details are sufficient. | Essential for detailed construction coordination (clash detection), precise cost estimation involving hardware, and planning fabrication/assembly sequences. It validates constructability. |
Which LOD is right for your project?
Selecting between LOD 300 and LOD 350 requires balancing the project’s specific needs against the budget and schedule. It is rarely necessary to model an entire building to LOD 350; rather, this level is usually reserved for complex areas requiring intense coordination.
- Project Needs: If the client requires a digital twin for facility management or if the project involves complex prefabrication, LOD 350 provides the necessary data. For standard projects where field-fitting is acceptable for connections, LOD 300 often suffices.
- Project Stage: LOD 300 fits the Design Development and Construction Documentation stages where the focus is on defining the scope and systems. LOD 350 fits the Pre-Construction and Fabrication coordination stages where the focus shifts to installation logistics.
- Team Capabilities: Modeling at LOD 350 requires high expertise. The BIM team must understand construction detailing, not just software tools. If the team lacks construction experience, attempting LOD 350 can lead to inaccurate models that create confusion.
- Collaboration & Coordination: If theproject utilizes a “Big Room” collaboration environment or requires zero-clash tolerance (e.g., hospitals, labs, industrial plants), LOD 350 is mandatory for avoiding costly field change orders.
- Budget & Time: Higher detail requires significantly more modeling hours and larger file sizes. LOD 350 increases the cost of retrieval and model maintenance. Decision-makers must assess if the reduced risk of field errors justifies the increased upfront cost of LOD 350 modeling.
In conclusion, LOD 300 confirms the design intent, while LOD 350 validates the constructability. However, in practice, these levels can be applied flexibly across both design and construction phases. Depending on the specific focus of the Designer, Owner, or Contractor for a given area or system, a project can seamlessly integrate both levels. Successful BIM execution plans often utilize this hybrid strategy, specifying LOD 300 for general elements while dedicating LOD 350 to congested plenum spaces, mechanical rooms, and structural connections to manage high-risk conflicts.
