Is a single source of truth a prerequisite for Level 3 BIM?

The message is clear: as well as being an absolute requirement for government works, the Level 2 mandate has to be complied with, across all stakeholders, before we can even consider introducing Level 3.– David Jellings, BIMObject UK

Before we tackle Level 3 BIM, we need to master Level 2 and provide a single source of truth, says David Jellings, managing director of BIMObject UK.

The plethora of Level 3 BIM conferences undoubtedly confirms its status as a hot topic. However, mindful of the need to make sure we are not attempting to run before we can walk, at least two things need to happen before Level 3 BIM can succeed.

Level 2 BIM must be mastered and correctly implemented. We must be able to provide a single source of truth.

It seems reasonable to assume that mastering Level 2 is obvious. However, having had discussions in the context of Level 3 with many industry players, from new entrants to advanced practitioners, I find that often, the importance of Level 2 is not fully understood.

The deadline for mandatory Level 2 BIM has long been and gone, with barely a murmur from a normally vociferous industry. It’s almost as if it never happened.

Could this be because the industry believes we have already achieved PAS 1192 and therefore all we need to do now is wait? Or could it be that by keeping heads below the parapet, it may go away?

Whatever the reasons, we must get Level 2 right before we can contemplate implementing Level 3. This is because the latter will necessitate the sharing of defined data outputs with many other bodies and the whole point of the former is to create that data in a consistent and defined manner. To do anything else means we are not performing at Level 2.

A key requirement of this process is the ability to define, select and model the components that are used to assemble the finished construction, whether they be simple objects like furnishing and finishes, or more complex assemblies such as walls, ductwork or systems. In the BIM world, they are all important. Level 2 provides the framework to ensure that they are correctly represented in the model.

So the message is clear: as well as being an absolute requirement for government works, the Level 2 mandate has to be complied with, across all stakeholders, before we can even consider introducing Level 3.

The importance of a single source of truth

In information systems design and theory, single source of truth (SSOT), is the practice of structuring information models and associated data such that every data element is stored exactly once.

In practice this means that there is only one repository for any data element – the primary source. Wherever this data is accessed from, the link is always back to this primary source.

The obvious advantage of this practice is that it maintains the consistency of data and prevents the creation of inconsistent duplicates. This applies to pretty much any business process and of course is highly advantageous to the construction process with its large number of stakeholders and diverse supply chain.

When the concept of SSOT is considered as part of wider data sharing (which will be a core deliverable of Level 3 BIM), its importance is even greater. In this process, data will be available outside of the construction supply chain, to many other bodies and industries – utilities, security, transportation and city planning to name but a few. The data supplied will be of no use unless it is consistent and complete: SSOT is a must.

Finally, most importantly, SSOT cannot be achieved using traditional file-based systems, which are difficult to control and easy to manipulate. It must be achieved in an easily accessible environment, which is exactly what the cloud provides.

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