LOD in BIM was first introduced by the American Institute of Architects (AIA) in 2008 at five different levels to introduce the details and specifications of a BIM-based element. It is worth noting that the concept of LOD has generally existed since before 2008, but was not explicitly and academically articulated by a specific institution.
The first experience of using LOD was with Vicosoftware company, which was able to relate its digital models to the cost information of a project and provide information and details of project elements at different levels and in a codified, design phase to professionals and Engineers involved in the project.

LOD standard

Level of details in BIM:

In 2011, BIMForum (a subsidiary of buildingSMART in the United States) began LOD development by forming a working group of designers and builders in the major disciplines (architecture, construction, electrical, mechanics).

The working group first interpreted the basic definitions of AIA (Society of American Architects) and collected examples to illustrate these interpretations.

These samples are published in the form of a book every year and are provided to experts.
Due to the importance of the concept of BIM in the world and also the approach of buildingSMART to provide global infrastructure for the use of this concept in the construction industry, the LOD Specifications handbook has been published regularly since 2013.

The LOD Specification is prepared and published each year using the definitions in the AIA for the AIA G202-2013 Building Information Modeling Protocol Form and in a specific format in the CSI Uniformat 2010 standard.

LOD

BIM allows us to deal with different levels of detail based on our experience and project needs in BIM modeling, which are called LOD (Level of Development) that contains of lod (level of details) +loi (level of information). The classification of LODs starts from LOD 100 and can continue up to LOD 500,

 lod & loi

lod with loi

According BIM standard (iso-199650) level of development define in 5 parts that’s are:

LOD 100:
This level is actually a simple form of outline. At this level, the BIM elements are displayed as symbols and have no complete resemblance to the real element.

LOD  200:
Each graphic element is represented as an overview of the actual design with approximate dimensions, shape, position of the element and placement.

LOD 350:
At this level, each BIM model must be presented as a complete and more detailed design in terms of element sizes, original shape, coordinates and even materials. At this level, each element is represented with the necessary details to coordinate with the execution plan. For example, how to connect a metal column with a base plate.

LOD 400:
At this level, in addition to the above information, the details of the connections and the method of connection and… are specified. For example, the length and dimension of welds and their exact location.

LOD 500:
In general, this level is not much different from LOD400 and can only be said to include the structural title and information needed to manage and complete the BIM model, in other words, non-graphical information may be attached to the elements model.

For example: date of manufacture, manufacturer specifications and attachment of the actual image of the element.

LOD100-500

The difference between a CAD model and a BIM model:

One of the differences between a CAD model and a BIM model is the level of LOD display quality. That you are familiar with But you should know that not all modeling software can have this level of display or support this level.

For example a Sketchup software model, or a 3dMax software model as a graphic software or a model Rhino software as an industrial software can never follow the LOD BIM design If only up to LOD -200 level.

And you must use modeling software that is programmed based on BIM. Like Revit, Archicad ,Tekla and.. , as long as you follow the rules and regulations of following an LOD model while working with these softwares.

That is, the detail leveling is classified in a model and modeled with details.