BIM Level of Development (LOD): 100, 200, 300, 350, 400, 500 Standards & Examples

Building information modeling (BIM) is a sophisticated process for creating and managing different aspects of construction projects using a centralized 3D BIM model. Its primary use case spreads over the AEC fields and professions, and it should cover the entirety of a project’s lifespan, from the earliest design iterations to post-construction maintenance and even eventual deconstruction.

The integration of BIM into the construction industry has been rather challenging. Despite the fact that BIM itself is a collaboration-oriented methodology, creating a framework in which different project teams and stakeholders can collaborate has been one of the most noteworthy challenges in the construction industry.

The lack of clear standards in the field has heavily affected how many BIM solutions approach cooperation and interoperability. Right now, it is still easier for smaller solutions to support the file formats of industry leaders such as Revit to achieve better chances of compatibility rather than relying exclusively on open standards such as IFC or COBie. You can learn more about interoperability in BIM and how it differs from compatibility in this article.

However, the incompatibility of data formats is only one aspect of this issue. Another example of communication difficulty is the inability to properly communicate the level of detail and completion for specific elements of BIM models, since many companies have their own terminology and expectations for different construction phases, even after the introduction of BIM.

The introduction of Levels of Development (LOD) was supposed to resolve this issue, and it has managed to do so to a certain degree.

What is a Level of Development?

An LOD, a Level of Development (or Level of Detail), is a standardized specification that simplifies the communication between industry experts in regards to BIM implementation in specific phases of construction. BIM itself is a very challenging methodology with many elements and levels of implementation, which is why there are also different degrees of development.

The primary purpose of LODs is to define the contents and the reliability of BIM elements in a specific phase of a project in accordance with six existing LODs:

• LOD 100
• LOD 200
• LOD 300
• LOD 350
• LOD 400
• LOD 500

It should be noted that the original introduction of LODs by the American Institute of Architects in 2008 established only five distinct levels of development. LOD 350 was added by the BIMForum working group.

The actual first example of an application of LODs in the history of this industry is often attributed to Vico Software, a software provider that developed construction analysis solutions. Their technique of linking digital models at different project phases to total project costs closely resembles LOD.

What is the difference between a Level of Development and a Level of Detail?

The term “LOD” has been in the construction industry for over a decade now, but many people still describe it as Level of Detail rather than Level of Development. While it is true that both terms are closely related to each other in the context of construction processes, using them interchangeably is incorrect.

A Level of Detail represents all of the graphical and visual content in a BIM model, and it is also often used to describe the visual complexity of 3D models. The “Level of Detail” metric explains how detailed the different elements of a BIM model are at a specific point in time.

A Level of Development, on the other hand, is a representation of reliability and the development progress of specific BIM elements. One of the easiest ways to describe a “Level of Development” is to treat it as a “maturity” meter for BIM objects, where LOD 100 is a rough plan of what the object will be, while LOD 500 is a complete BIM object with all the information necessary to begin on-site construction.

How does the Level of Information fit into this context?

The distinction between a Level of Detail and a Level of Development should be easy to see by now. However, we would also like to make the matter even more straightforward by introducing another term: Level of Information.

A Level of Information (LOI) is the aggregation of all the non-graphical information embedded in a BIM object at a specific point in the construction project. Most of the information stored as a LOI can be considered metadata: everything that can enrich the original object beyond its geometrical shape, including warranty details, manufacturer information, performance specifications, and many other examples.

The reason we bring a seemingly unrelated term into the discussion of how LODs should be treated is that a Level of Development at its core is a combination of a Level of Design and a Level of Information. It is an “umbrella term” of sorts that combines the two lesser elements into a single term.

This should offer a clear explanation of why it is important to draw a clear distinction between a Level of Development and a Level of Detail.

The design phase and LOD

The nature of LODs heavily suggests that they would be focused on the design phase of a construction project and nowhere else. However, it would be a lot better to reverse that suggestion and say that the global completion of the design phase and the subsequent transition into the construction phase can be explained and described with LODs.

One of the biggest reasons for this approach is the fact that the distinctions between large phases of a project are not clearly defined or standardized anywhere. The lack of a universally accepted standard leads many companies to develop their own approaches, which creates friction or even conflicts during collaboration. In some cases, there may even be different standards within the same construction organization depending on the project type and its requirements.

Additionally, the progression of different design phases and elements differs from one use case to another due to the sheer number of BIM elements that a single project might include. For example, if a single BIM object in the design has reached LOD 200, it is completely possible that some other objects are already at LOD 300 or have barely made any progress and are still at LOD 100.

The context of both examples above should improve the understanding of why it is somewhat incorrect to say that LODs are only applicable to the design phase (since some LODs are only applicable outside of the design phase).

Now that we have an abundance of information about LODs as a concept, it is time to move over to each of the Levels of Development in more detail. We are also going to try and showcase how third-party BIM solutions such as Revizto can assist in different ways for each of the LODs.

Additionally, while the concept of LODs can be applied to specific objects in a BIM environment, our explanation is going to assume that the entire BIM model is created in accordance with a specific LOD for the sake of convenience.

LOD 100 – Conceptual Design

LOD 100 is the conceptual design phase of a BIM model, comprised of basic elements without specific definitions or dimensions. The primary purpose of LOD 100 elements is to offer general resemblance to the future building’s elements in shape and size.

Most of the time, LOD 100 is used for situations like these:

• Early cost estimation and budgeting, made possible by the rough representation of the size and the scale of the future project.
• Conceptual modeling is a necessity early on to have an understanding of the overall design intent and the potential spatial relationships between BIM objects.
• Construction site planning is conceived with LOD 100 in mind due to the ability to provide a basic structural layout, zoning, and the orientation of the structure.
• Project feasibility is also included here, with general shapes and dimensions assisting in the basic evaluation of whether a project is even viable and worth investing resources into.

The basic examples of LOD 100 elements and objects are the most fundamental construction elements one can think of. The walls are basic blocks with no material or dimension specifications, the roof is a simple surface, the entire structure is comprised of simplified beams or columns as its structure, with only rough estimates of where they will be placed, and so on.

Third-party BIM solutions like Revizto can be used at LOD 100 for improved collaboration between stakeholders while also providing the possibility of tracking large-scale issues in these basic models.

LOD 100 often uses basic block models as representation for its level of development, with multi-story office buildings looking like combinations of identical rectangles on top of one another. The primary purpose of this level of development is to offer a generalized overview of the scope and complexity of the project without all the details and specifications. It is the best possible approach for conceptual design and early planning.

LOD 200 – Schematic Design

LOD 200 is a direct evolution of LOD 100, offering more defined shapes and sizes with more accurate object location (although they are still approximate and not specific). The general configuration of BIM objects should now be easily visible with the objects’ geometry alone, without the intricate details of the later LODs.

LOD 200 has a number of primary use cases, including:

• Basic internal systems such as electrical, plumbing, and HVAC are introduced here as a showcase of the amount of space they will occupy and the approximate location of these systems.
• Geometrical approximation for all objects is now much more defined than before, although they are not fully detailed and accurate yet.
• Moderately accurate spatial coordinates should also be introduced at this stage for most design elements to locate and resolve major conflicts and clashes.
• Information placeholders should be included at this stage, with certain components being relatively close in shape to what they will look like (no manufacturer-related or specific model information).

With LOD 200, most models take on a far more detailed shape than before. For example, walls are now closer to their real-life counterparts in terms of location, thickness, and so on. Basic structural information such as the marking of load-bearing walls and columns is added here. The roof is now more accurate, with overhangs and a basic pitch closely resembling the real-life object. The positioning of various structural elements should now also be far more defined.

Third-party BIM solutions like Revizto offer assistance at LOD 200 by providing schematic design overview capabilities, along with coordination issue tracking and the aggregation of opinions and inputs from different stakeholders. They can also improve early clash detection by visualizing them in an obvious manner, making obvious clashes more difficult to miss.

With LOD 200, the representation of the future structure becomes far more defiled without including the exact definitions of real-life objects and elements. No performance specifications, materials, or exact dimensions are involved at this phase. The purpose of this level is to introduce more accuracy as a means of basic interdisciplinary coordination to resolve the most noteworthy clashes as early as possible.

LOD 300 – Detailed Design

LOD 300 is where the exact specifications of BIM objects come into play, with specific information about each object’s dimensions and positioning. It should already be accurate enough to be acceptable for fabrication plans and other construction documents. An LOD 300 BIM model can be used as a reliable representation of the future structure with all of the components coexisting in the same environment with high precision.

The most notable use cases for LOD 300 objects are:

• Detailed interdisciplinary coordination as a continuation to the efforts made at LOD 200 to iron out less significant and smaller clashes between the different systems in a structure.
• Extensive scheduling and cost estimation are now possible due to the accuracy of LOD 300 BIM models.
• Accurate construction drawings can be produced with LOD 300 models due to the extensive level of accuracy involved.
• Fabrication and assembly processes can also be involved at this phase as a result of the real-life accuracy of each BIM object in a model.

LOD 300 is where all the construction elements in a design become as accurate and detailed as they were before BIM was introduced to the industry. Every single element of the project is now ready to be fabricated and used in construction. Walls now have highly accurate dimensions, as well as the specific materials used and other necessary elements, such as insulation or cladding. Roofs are now equipped with drainage, waterproofing, and exterior design elements. The structural elements of the building have specified material types, exact dimensions, and specific placement.

Third-party BIM solutions like Revizto can be used to review BIM models at LOD 300, providing seamless real-time interaction to avoid miscommunication and other similar issues.

The most basic explanation of LOD 300 is “the ability to construct” – the accuracy and precision would make it possible to create the entire structure this early on if it were not for all the different BIM elements that are yet to be introduced. This level of detail dramatically improves the coordination between stakeholders while simplifying scheduling, improving cost estimation, and dramatically reducing the number of conflicts between the BIM objects in the structure. However, this does not include all the different connection elements and installation instructions, both of which are now delegated to LOD 350.

LOD 350 – Construction Documentation

LOD 350 was introduced as a means of improving upon the previous level of development by introducing certain supplementary elements and information that is necessary for actual construction coordination. Accurate on-site installation or assembly is the primary focus of this phase, making it possible to not only see the model itself as it would be in the real world but also to plan the construction processes it would take to create the structure using various construction elements.

LOD 350 elaborates on several elements of LOD 300:

• Installation-related information is added to ensure that all of the structural elements can be reproduced in real life and installed as intended.
• Multiple supportive elements of the construction are introduced, such as fittings and connections, bolts, brackets, joints, and everything else needed to reproduce the BIM model in real life.
• Integration between structural elements is improved upon even more via the detailed explanation of how various supporting frameworks will work together (structural supports being connected to mechanical ductwork and electrical routing through walls).

LOD 350 improves the accuracy of BIM models by the addition of many construction-centric details that facilitate the reproduction of a BIM model in reality. Walls and roofs now have the detailed positioning of all supportive systems such as electrical or plumbing, as well as the studs and mounting points necessary for connecting construction elements to one another. The structural elements include the exact positions of welds, bolts, plates, and other supportive elements, showcasing the way they will be connected to one another to create a stable and reliable structure.

Third-party BIM solutions like Revizto gain an increased level of importance at LOD 350 by facilitating collaboration while also identifying potential constructability issues with the ability to resolve them in a short time frame.

The point of LOD 350 is to introduce information related to construction coordination, especially when it comes to installing different structural elements. The ability to showcase construction information with this level of accuracy facilitates improved on-site coordination and dramatically reduces the number of potential errors that would have to be resolved on-site.

LOD 400 – Fabrication

Fabrication and assembly are the primary touchpoints for LOD 400, and the most notable addition of this level is the introduction of various fabrication specifications and instructions for assembly. LOD 400 is commonly used in modular construction, part fabrication, and the creation of shop drawings, with all the elements being completely prepared for fabrication and assembly.

The most notable use cases for LOD 400 are:

• Modular construction with LOD 400 allows for entire building modules to be designed and fabricated before being transported to site. The information in a BIM model should also dramatically decrease the amount of work it takes to assemble the modular element after it has been delivered to the construction location.
• Prefabrication is also completely covered by this level, adding all the information required to produce ductwork, beams, precast concrete, and other elements that rely on highly accurate modeling for them to be fabricated to speed up construction.
• Manufacturing is another potential area that could benefit from the accuracy and data that LOD 400 introduces, serving as a proverbial blueprint for manufacturing custom elements for construction projects.

Most structural elements benefit greatly from the introduction of LOD 400 due to the simplification of the process of their fabrication and assembly. This includes beams, columns, connections, etc. Doors and windows are also fit with specific frame profiles and all the necessary hardware such as locks and hinges, which allows them to be manufactured and installed with ease.

Third-party BIM solutions like Revizto can assist with managing and reviewing fabrication models at LOD 400. They also offer issue tracking capabilities specifically for prefabricated and modular elements.

One of the most notable improvements of LOD 400 over the previous levels is the introduction of product-specific information to BIM models and objects. All LOD 400 elements are completely identical to their real counterparts and ready for both production and installation.

LOD 500 – As-Built

LOD 500 is the highest level of BIM model development. It represents the complete model in its “as-built” form: the definite version of a BIM model that looks exactly how its real-life counterpart is supposed to look when it is completed. Every level mentioned above is included here, along with all the non-geometric information BIM models can provide, such as warranties, operation manuals, product specifications, and so on.

The most notable use cases for LOD 500 are:

• Expansions and renovations are made significantly easier when a LOD 500 BIM model is used as the baseline of the structure, simplifying the planning process for all parties involved.
• Facility management as a whole is dramatically improved due to the ability to track the performance and condition of different structural elements.
• Maintenance and repair tasks can be easily planned and scheduled when necessary due to the existence of detailed product information in an LOD 500 BIM model.

The exact materials and dimensions of all the structural elements of a building make it possible to track the wear and tear of these elements while also planning renovation operations when necessary. Being able to access detailed electrical system information simplifies power distribution management, and the accurate location of all plumbing systems simplifies potential repair operations.

Third-party BIM solutions like Revizto offer simplified comparisons of BIM model data with actual construction information on-site while providing easier access to the model post-construction for easier renovation and maintenance efforts.

The primary use cases for LOD 500 are maintenance and facility management – all of the tasks that are performed with a structure after it has been constructed. It is often considered the final stage of the BIM development process, offering the most accurate representation of a real structure to serve as a reference for multiple different post-construction operations.

Advantages of LOD in BIM projects

Navigating between different LODs and stages can be challenging, especially on large construction teams. However, the existence of such a standard still makes it easier to manage than working without any kind of standard to begin with.

Most teams start at LOD 100 or 200 in early design phases to create concepts and test their feasibility. Models evolve to LOD 300 when the concept is decided upon and the model becomes more detailed, intensifying the collaboration between various systems, MEP and others. The introduction of LOD 400 is made closer to the construction phase itself to simplify and streamline fabrication and installation processes, while the update to LOD 500 is reserved for when the entire model is finished and no longer modified in any way until construction processes are complete.

The most notable advantages of BIM levels of development are:

• LOD standardization allows stakeholders to have an understanding of what to expect from different project phases, reducing ambiguity and facilitating better collaboration between departments.
• The use of LODs prevents design conflicts by making it easier to track whether the project evolves in a structured order and is well-paced.
• The efficiency improvements from different LOD phases are also possible, such as the use of LOD 400 for improved fabrication and LOD 500 for maintenance or renovation tasks.

Conclusion

Level of Development is an important framework for BIM models that serves as an explanation for what the current state of development of the model or object is. The purpose of each of the six LODs is clearly defined, building on top of one another’s achievements to get to LOD 500 in the form of an as-built BIM model.

While the majority of LODs affect only the design phase, it would not be correct to assume that this classification is not applicable to the rest of the project realization process. On the contrary, the “final” state of LOD is only applicable to projects that are already in their post-construction phase, way past the design phase.

It is important to balance cost, accuracy, and deadlines by selecting the right levels of development at different stages of project completion. Spending a lot of time on details in early project phases might slow down the rest of the project to a crawl, but failing to add more details to the project model before the construction phase might lead to a lot more clashes and rework on-site.

A delicate balance needs to be maintained in these situations, a balance that solutions such as Revizto can help maintain by assisting companies at each of the LODs in different ways, ultimately simplifying and streamlining the construction project realization process.

Frequently Asked Questions

What is the difference between the LOD 500 As-Built model and a digital twin?

An LOD 500 model is a perfect baseline for the digital twin initiative, and the former can be turned into the latter by integrating a number of IoT sensors into the structure and linking them with the BIM model. This is the only major difference between the two.

What are the most notable challenges for consistent LOD adoption?

Consistent LOD adoption in large projects can be challenging because of the different software solutions, expectations, and workflows on different teams. The lack of standardization and communication issues can also play their part in expanding this issue.

Is it possible to customize LOD standards for specific project types or use cases?

Yes, LODs can be customized to a certain degree depending on the project type and other factors. For example, infrastructure projects might have to put more details into their LOD 400 for various underground railway utilities.

How do clash detection processes change depending on the current LOD?

Clash detection can be a flexible tool at different LODs. Major spatial conflicts are the primary target at LOD 200, while LOD 350 and 400 focus more on smaller issues between elements such as ducts, bolts, connections, etc.

Can LOD help when it comes to collaboration between stakeholders with different BIM solutions?

LOD is more or less universal and not dependent on specific BIM software. This way, it can be used as a great tool for the alignment of efforts by using specific LOD levels as the baseline. The effect of universal data formats such as IFC is still more significant, but the benefit of LODs is undeniable, as well.