What Is LOD – The Level Of Detail Of BIM Elements?

Dear TeamCAD website visitors,

We continue to cover interesting topics related to the BIM workflow. As I announced in my previous article, “What Is BEP And What Should It Contain?”, in this article, I am going to cover a topic about LOD – Level Of Detail of BIM model elements.

What Is LOD – The Level Of Detail Of BIM Elements?

The Level of Detail of BIM elements or LOD is a chapter of BEP (BIM Execution Plan). In BIM terminology, it presents a precise description of all typical elements in the BIM model, both in terms of graphic details of BIM elements and in terms of quantity type data that the BIM element should contain. The level of detail of BIM elements is usually directly related to the work and data delivery at certain phases of the project, so it can be safely concluded that the level of detail of BIM elements defines the graphical appearance of BIM elements and the type and quantity of data allocated to BIM elements during and at the end of each project phase.

All of the above leads us to the logical conclusion that the levels of detail of the BIM elements change at each project phase during the project life cycle. One has to be very careful about the required level of detail of BIM elements during each project phase, primarily for coordinated exchange of BIM data during the BIM project process and then for financial reasons, since all participants in the project process should be aware of the fact that the higher requirement in terms of the level of detail of BIM elements at some phase of the project, the higher work, and therefore the higher cost of generating BIM geometry and data in the BIM discipline model.

After defining exactly what the LOD or the level of detail of BIM elements means and explaining in principle the relationship between the level of detail of BIM elements and project phases, logical questions arise:

  • Who defines the level of detail of BIM elements?
  • How to define the level of detail of BIM elements depending on the project phases?
  • Do the graphic level of detail of BIM elements and level of detail of data have to match?
  • How to verify the implementation of BIM element LOD?
  • Is the chapter on the LOD of the BIM elements sufficient to ensure efficient coordination of the BIM model and the exchange of data from all participants in the BIM project process?

What is LOD

Below, I will give you a detailed answer and explanation for each question asked.

Who defines the level of detail of BIM elements?

Bearing in mind that the interests of the designer, contractor and investor do not completely coincide during the BIM project process, I do not think it is possible to give a simple answer to the question which party in the project process needs to define precisely the level of detail of the BIM elements.

First, it should also be borne in mind that the BEP chapter, which deals with the level of detail of BIM elements, most commonly defines the graphical layout of BIM elements and the data assigned to those elements in BIM discipline models. Indirectly, the BIM element LOD also affects the multidisciplinary BIM workflow and data sharing in a multidisciplinary BIM environment by placing clear requirements on the BIM element LOD in front of the disciplines designers, both graphically and in terms of data that the BIM discipline model should include. All this provides a framework for discipline designers to exchange information efficiently from the BIM discipline model, and it is therefore very valuable to set the level of detail of the BIM elements to the discipline designers, which would allow them to exchange data as efficiently as possible within the BIM project process during a particular project phase.

Considering all the above in the article section on who defines the level of detail of BIM elements, I think it is most logical that the investor is a participant in the project whose interest is to manage the LOD requirements of BIM elements for each discipline in the BIM project process. The reasons for this are many, and I m going to list only the most important:

  • better control over the process of generating graphic documentation and data in BIM discipline models at each project phase;
  • optimized transition to the next phase of the project in the BIM project process;
  • easier establishment of automation of the BIM project process, which results in the absolute accuracy of the generated data and more efficient exchange of data between different disciplines in the BIM project process; more on that topic, you can find in the article „BIM Workflow Automation“
  • reduction of design costs through automation of the BIM project process;
  • By controlling and managing the LOD requirements of BIM elements, the investor gets a cheaper BIM as built model, which can serve as a very good basis for the FM model and digital twin model; read more in the article “What Are The Digital Twins?”

What is LOD

Following the reasons why an investor should manage the LOD requirements of BIM elements, it is important to note that it is very easy for an investor to achieve the above goals by hiring a BIM Manager or BIM Consultant, who with his knowledge and experience could bring significant financial savings to the investor through optimization of requirements of the LOD of BIM elements at all phases of the project in order to establish the most efficient BIM project process.

How to define the level of detail of BIM elements depending on the project phases?

Fortunately, the answer to this question is not that complicated. Specifically, the BIM project process monitors the requirements of each project phase, so the direct relationship between the LOD of the BIM elements and each project phase is more than obvious, with some exceptions.

I m going to try in a very simple way to explain the requirements of each LOD of BIM elements during the project phases through a very simple example – the evolution of the door LOD through the different phases of the project:
LOD 100, LOD 200, LOD 300, LOD 350, LOD 400, LOD 500

After a very simplified way of reviewing the requirements of the LOD of the BIM elements according to the project phases, I think it would be useful to also make a description of each level of detail of the BIM elements – LOD level:

  • LOD 100:
    • graphic requirements – the most basic 3D geometry;
    • parameters – the most basic geometry without material data;
  • LOD 200:
    • graphic requirements – 3D geometry;
    • parameters – the most basic data of elements materials;
  • LOD 300/350:
    • graphic requirements – 3D geometry with details sufficient for the preparation of tender documents;
    • parameters – information on the materials of the elements sufficient for the preparation of the tender documentation;
  • LOD 400:
    • graphic requirements – detailed 3D geometry with details sufficient for the construction state project;
    • parameters – information on the elements materials sufficient for the construction state project;
  • LOD 500:
    • graphic requirements – detailed 3D geometry with details sufficient to produce the as built project, FM model and digital twin;
    • parameters – data on the materials of the elements sufficient to produce the as built project, FM model and digital twin;

Do the graphic level of detail of BIM elements and level of detail of data have to match?

The answer to this question may be a conditional yes. Namely, in practice, I often encountered different requirements in terms of the LOD of BIM elements which were not strictly following the typical requirements of the project phase ie. according to the brief overview given in the previous chapter of the article – comparing the BIM element level of detail from LOD 100 to LOD 500.

To tickle your imagination, I am going to give you a typical example that completely deviates from the schedule view of the LOD 500 of BIM elements during the various phases of the project. Take elevator geometry and elevator data, for example. In the FM model and the digital twin model of a constructed building, for example, the elevator can be presented geometrically as a simple prism, while in terms of parameters and data it must be presented in much more detail. Elevator data in the FM model and digital twin model must provide information about who the elevator manufacturer is, what material the elevator was made of in the BIM model, when the previous elevator service was, when the next elevator service is, how many people can fit in the elevator, cable data and other details related to elevator lifecycle monitoring, etc.

After this very simple example regarding the LOD requirements of the BIM element related to the elevator in the FM phase of the project or the digital twin model, I think it is clear to you why I initially answered the question as a conditional yes. In this regard, I hope you understand that LOD 200 or LOD 300 is sufficient for the graphic requirements of the elevator, while the LOD 500 is required for parameters and data for the FM model or the digital twin model to fulfill all requirements for an adequate LOD of the BIM elements.

How to verify the implementation of BIM element LOD?

The most logical answer to this question is that the investor should verify that all requirements related to the LOD of BIM elements in the BIM project process have been met. The simplest way for an investor to do this is to hire an experienced BIM Manager or BIM Consultant, who would check, in the interest of the investor, the degree of implementation of the BIM element LOD in the BIM discipline models.

To avoid any complications and to identify any shortcomings in the BIM discipline models on time, it is best to organize periodic virtual multidisciplinary BIM meetings, where a mutual review of all BIM discipline models is conducted. Such a process would prevent any problems in reaching the required LOD of BIM elements in the BIM model of any discipline and would give sufficient time to all project participants to remedy any deficiencies if they were noticed at any time during the BIM project process.

What is LOD

Is the chapter on the LOD of the BIM elements sufficient to ensure efficient coordination of the BIM model and the exchange of data from all participants in the BIM project process?

The answer to this question is short and simple – no. Although the chapter on the LOD of BIM elements can serve as a very good starting point for effective coordination of the BIM model and the exchange of data of all participants in the BIM project process, the process of BIM workflow coordination between disciplines, as well as the data exchange between participants in the BIM project process belongs much more to the BEP addition called “BIM Modeling Convention”.

This document describes in detail the way and techniques of BIM modeling of each discipline, BIM workflows for automated and optimized data exchange between disciplines, the process of BIM multidisciplinary coordination, ways of data visualization, etc.

What is LOD

At the very end of the article, I would like to give a brief recapitulation related to the article on LOD – Level of detail of BIM elements. The level of detail of BIM elements is an integral part of BEP, which further clarifies the required LOD of BIM elements, both graphical, parameters and data. The BIM element detail levels are usually defined from LOD 100 to LOD 500. It is common for the LOD of the BIM element to match the project phase in which it is generated, but this rule may not always apply. The most common discrepancies in this regard are with the FM and digital twin models. The LOD of BIM elements is an excellent starting point in defining and coordinating the BIM model of disciplines, both graphically and in terms of a framework for coordinating and exchanging data of all participants in the BIM project process. However, the LOD of the BIM elements does not fully regulate the multidisciplinary BIM workflow, but rather it is governed in the best way by the “BIM Modeling Convention”, of which I will provide much more information in the following article.

I would also like to conclude this article “What Is LOD – The Level Of Detail Of BIM Elements?” and my understanding of how it can assist the investor in all phases of the project process through optimization and automation of the BIM project process, optimization of multidisciplinary coordination and improved implementation of the BIM project process. I would also like to take this opportunity to announce to you my next article, „The BIM Modeling Convention“.

If you have any questions, comments or want to know more details about the topic I covered under “What Is LOD – The Level Of Detail Of BIM Elements?”, please contact TeamCAD, who will be happy to provide you with additional information.

Also, if you need any help with making LOD of BIM elements or BIM consulting services to optimize the BIM project process, TeamCAD will be happy to support you.

Until next time,
Predrag Jovanović

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