VIEWPOINT: In LOD we trust?
Mandeep Bansal, technical services manager of Knauf, calls for greater understanding of LODs and their differences if BIM 2016 targets are to be properly met.
Building Information Modelling (BIM) is still a relative newcomer to the UK and one emergent term, LOD, carries the potential for erroneous assumption and confusion. Given governmental enthusiasm for BIM, it is important that there is greater discussion about its terminology and reaching shared understandings if its 2016 targets are to be met.
Some traditionalists would say that this stands for Level of Detail; other revisionists would now argue for Level of Development. Confusingly, it would be fair to say that the definition is dependent on the context, depending on who you speak to.
Level of Detail commonly refers to appearance, geometry and the aesthetic of a design, in ‘our world’ building elements. The Level of Detail of a building information model increases as the project proceeds, in essence from a design intent to a more virtual construction model. But then again, Level of Detail can actually go backwards. The realities of a project usually mean you use the highest Level of Detail at the beginning to sell the design to clients and stakeholders
The inclusion of data within BIM models starts the evolution towards graphics and data, known as Level of Development. Again, similar to that of Level of Detail, the data model can increase in appearance and geometry but you can find a richness of information in relation to the product or building systems chosen.
The database can include manufacturer information, pricing, physical information (such as weight, size and material finish) and even down to electromechanical data for devices in the building! It’s important to note one would not need this Level of Development when selling a design to a client from the offset.
The key difference between Level of Development and Level of Detail is that the building elements’ geometry and attached information data brings the ‘product to life’; it allows various model users to gain reliable thought through information during the various phases of a scheme.
For example, tier 2 contractors probably would not care what the building elements look like from a geometrical representation but would be more interested in manufacturing information to enable them to cost and order materials. They are specialists in their respective fields and do not need to know the finer aesthetics of what they are installing. So why the detail?
It is important when discussing LODs to clarify what is meant: Level of Detail or Level of Development? Any misunderstanding can lead to unnecessary work being carried out. The key here is to understand the project brief. The introduction of BIM Execution Plans and through the early adoption of BIM over the next few years, closer collaboration will lead to a successful productive industry.
Mandeep Bansal
Technical services manager
