The BIM surveys we produce at LA Surveys can be at a range of ‘Levels of Detail’ (LODs) to suit the specific project. This means exactly what it suggests – it’s the amount of detail we show in our models (and resulting drawings) from what our scanners captured in our measured survey.

Depending on the complexity and scope of a project, the Level of Detail can range from a pre-design conceptual model to a highly detailed, “as-built” model that can be used in perpetuity by facility managers post-construction.

LA Surveys director Cristian Tudose and surveyor Clinton Tetteyfio answer some common questions to help you determine the appropriate Level of Detail for your project:

What are the different Levels of Detail?

In Building Information Modelling (BIM) standards, there are generally six levels of detail, ranging from LOD 100 to 500.

Here is an overview of what they mean and the stage in a project at which they are used:

LOD 100

An LOD 100 model provides a pre-design level of detail. It is a conceptual model that defines parameters like height, area, volume, orientation and location. Any information in the model is considered an approximation at this level.

LOD 200

This is the schematic design level of detail. An LOD 200 model shows geometric elements such as doors and windows with more accuracy than LOD100 but not necessarily accurate to specific products.

An LOD 200 model may also include non-geometric information such as defined materials and equipment, but this is considered an approximation at this stage.

LOD 300 and 350

The majority of our surveys are carried out at either LOD 300 or LOD 350, which is the building design development stage. The geometry and features of the graphical representations are considered precise at LOD 300 and 350 compared to the more approximate representation of LOD 200.

An LOD 300 or 350 model shows how an element will be installed. At LOD 350, it also shows how it interacts with other elements in the building.

LOD 400

An LOD 400 survey is the construction stage and includes even more visual information at a fabrication level of detail. An LOD 400 model is useful for suppliers who are manufacturing elements such as custom staircases, floor finishes and joinery. While LA London will produce LOD 400 models in their role as Architects, LA Surveys rarely need to go to this level of detail, unless there is a particular need to (more below) or if we are surveying a finished project.

LOD 500

This provides an as-built level of detail and shows building elements that are accurate in terms of shape, size, quantity, orientation and location post-construction. LOD 500 models can be useful for sales and marketing purposes as well as ongoing property maintenance, especially for buildings with full-time facilities management.

What’s the difference between LOD 300 and LOD 350?

An LOD 350 provides precise geometry with connections. Like the LOD 300, elements within the model are graphically represented in terms of their geometry. The LOD 350 goes a step further, however, by showing how they interact with other building systems.

Why would I want LOD 400 instead of LOD 300?

Most of the projects we complete at LA Surveys are LOD 300 or 350. However, there are occasions when LOD 400 is needed.

For a recent project, for example, we were surveying a building that had steelwork connections, with 12 bolts per connection. The lowest point of these bolts was going to dictate the ceiling height in each room. In this instance, it was crucial to include this additional level of detail so we could provide accurate measurements that would allow the Architect (not LA London on this occasion) to set the ceiling heights.

Visible steelwork connections in a recent project.

If you’re unsure what Level of Detail your project will require, the team at LA Surveys can advise you.

Does a higher LOD survey take longer?

Yes. A higher LOD survey typically requires us to scan at a higher resolution and capture more scans for more comprehensive data sets, which in turn takes longer to complete. However, it would rarely push a one-day scan into a two-day scan, which is where a client would notice the extra time.

The modelling time also typically takes longer, almost doubling, as every element needs to be modelled and checked

Our BIM model for Anstey Hall in Cambridge.

Does a higher LOD survey cost more?

Yes. Because of the additional timeframes outlined above, there is an associated additional cost. To give an idea of the difference, an LOD 400 survey might be almost double the cost of an LOD 300 or an LOD 350 one.

For more information on our measured surveys or to discuss your project, please contact us.

‘Levels of Detail’ Explained