BIM data: The great advantage of having an information model
We often say that BIM design software allows you to manipulate a graphical database. Many people who begin working with this methodology understand the concept very well, but little by little, as the weeks go by during the completion of their first project using this system, they tend to forget the importance of this crucial aspect. The transition from 2D to 3D is not easy , and even less so with other dimensions.
Within a BIM model , in addition to the parameters that allow us to control the geometry or appearance of the elements embedded in the model, there is a multitude of information that we use in post-design phases to exploit it and get the maximum possible benefit. When performing audits, both follow-up and phase changes in the construction process, it is common to find certain parameters missing information that should (or should not) be filled in . The metadata of a BIM model can be very extensive and varied, which is why different parameterization standards or classifications are often used. After all, they are a language, and it is important that we use the language our collaborators understand. These “languages” can serve two purposes: classifying the elements of our model is the first, and standardizing the information associated with the objects or construction elements is the second.
Although it may seem confusing at first, it is very important to understand the difference between classification systems and parameterization standards, since we use them to extract different information from a model.
Classification systems:
They are tools through which we can organize and retrieve information specifically designed for the construction industry . These help us identify an element thanks to standardized coding, so we know, for example, what its function is. In Revit, a facade and a partition wall are created with the same tool and even belong to the same category. If we wanted to differentiate them in some way, we would have to do so through a classification, so we can differentiate elements by their constructive function and not by the tool used to create them within a given software.
There are different types of classification systems, the most commonly used are:
- OmniClass: The OmniClass Classification System (OCCS) was developed by the OCCS Development Committee in collaboration with over 100 North American organizations, entities, and companies, including the American Institute of Architecture (AIA), Autodesk, buildingSmart, and others. It consists of 15 hierarchical tables, each representing a different aspect of building information (building entities by form or function, spaces by form or function, properties, materials, etc.). Each table can be used independently to classify a particular type of information, or can be combined with other tables to classify more complex topics. Among other classifications, OmniClass includes the UniFormat and MasterFormat 2010 Edition classifications.
- UNICLASS2015: This is a development of version 2 of UNICLASS, which is cited in the national prologue to ISO 12006-2 Building Construction. UNICLASS 2015 thus becomes the British response to the aforementioned international standard. Version 2 of UNICLASS was developed by the CPIc (Construction Project Information Committee). This organization subsequently transferred all intellectual property rights, as well as all documentation, to the United Kingdom government, which developed it in conjunction with the NBS (National BIM Society). UNICLASS 2015 also works through a set of hierarchical tables that allow us to enter information from a broad, general perspective to a much more detailed and specific one.
The Complexes table describes projects in general terms and can be used to define an activity. These complexes can be subdivided or broken down into Entities, Activities, and Spaces. For a more detailed design, however, the main starting point is entities. These entities are broken down into architectural components called elements.
It seems that British and American users have it easy, but what do we BIM users in countries that don’t have our own state-level coding do? The best thing to do is to find the classification system that best suits our way of working. In some projects, even developers offer their own classification system. In Spain, there is still no state-level classification system, but there is one at the regional level. Last June, GUBIMCAT (Catalan BIM Users Group) published the first version of the GuBIMClass classification system thanks to a joint effort with the Infrastructures entity of the Generalitat de Catalunya (Catalan Government).
In Revit we find various ways to classify each of our families:
The first is through family editing, where we already find a coding prepared solely for OmniClass coding. Revit is a North American software, so it was to be expected that they would do the same with an American classification system.
The second is through the famous assembly codes, in these we can insert the type of classification we want.
The third would be through keynotes and we could also use the classification system:
And we could even create different types of classification with project parameters created by us.