Updated: Apr 13
In the BIM industry, a lot of people are not aware of what exactly LOD (Level of Development) is. This is a very frequent question and many people have debated on the topic. In this post, we will introduce you to the meaning of LOD. You will learn how to use it and why it is so important part of BIM (Building Information Modelling).
Before we dive into these details, we need to answer the question “Why do we need to decide on a certain Level of Development?”. The fast answer would be to make things easier. Let's say we have a client who needs to provide us with information and details about the Project. Before we were given him the real references, for instance from the BIM Forum and he had to load and go through all the 250 pages of documentation. The problem here is that nobody has the time and wants to spend the effort of going through all of the papers. It’s just too much. On other hand, this amount of information could be very confusing to the client. Usually, he wants something particular and he would refuse to go through all the paperwork in order to give us a clarification of what exactly he needs and want from us.
So, it occurred the need to have all the information from those 250 pages and to simplify it and make it easier and quicker to understand. This way we are presenting well-structured information, which would help him to point out what his actual desire is. He could go through the document, see the images and understand what he will get.
So, what is LOD?
LOD is an individual component in the BIM model that has a certain of information - graphical, non-graphical, and documentation. This is very helpful when you build a digital model, depending on the phase you are at or depending on the needs. For example, if the client needs just a graphical representation of the building or the construction model only. This way the digital information would be correct and could be correctly designed in the digital environment, and the Contractor could easily direct and copy it. That’s why the document is so essential.
There are various explanations about what LOD is. Many companies interpret the concept in their own way. Marzia Bolpagni has published a diagram (LoX) (in Politecnico di Milano) which represents how many are organizations that are released different information, explanations, and interpretation of what LOD is. There are a lot of different and non-consistent opinions on the concept. There isn’t one document that explains what is LOD. The diversity of heterogeneous information, coming from various sources could be extremely confusing. Each country even has its own understanding and interpretation of LOD.
And if this is not confusing to you enough, yet, check out this - there is a document in BIM “ISO 19650” in which the name of LOD is changed to LOIN (Level of Information Needed), so it could fit their own standard. Maybe, after time the concept will be settled down and would bring equal meaning and value to anybody in the Industry. But for now, the different professionals and organizations refer to different meanings.
At the end of the day, it doesn't matter who and how LOD is interpreted but what value it gives to the client and how he (the client) evaluates it. Is it helpful enough? Are they able to easily understand what they need from that document?
There is another level of the LOD documentation - the responsibility of matrix which highlights at which stage, who is responsible for a particular level of information. For example, for the resources that could be tackled the color and the color at this stage has to be LOD 200 but the next stage should be LOD 300. So, it needs to be distributed properly. This could be very difficult because there are lots of components in the model and it’s hard to decide in which stage what information we really need, however, we still need to have the information in place because in the BIM execution plan we have to know when we are going to get a particular element, at what level of detail. This is the way we are ensuring that the project will run smoothly.
Is the size of the Project important for using LOD?
No, the Project scale does not really matter for the LOD because LOD could be applied to every Project. There are other factors that we have to pay attention to through the BIM workflow. Read more about how the Project Scale matters on BIM.