The buildingSMART Data Dictionary (bSDD) is an online RESTful centralised API provided by buildingSMART that allows you to search for standardised classifications and properties.

For example, if you want to assign a Uniclass classification system (popular in the UK) or an Omniclass classification system (popular in the US) to elements in your model, instead of downloading the classification system from their website, you can directly search the bSDD. This ensures that you are always up to date, and that codes are entered correctly (without spelling mistakes, correct formatting, etc).

The bSDD search results may also be filtered based on IFC class. This will make it quick to shortlist relevant classification codes and properties to a particular object.

The bSDD also stores information on whether or not classification systems require additional standard properties to be filled out, and whether they should be filled out in a particular way. For example, all countries need to fill out a “Fire Rating” property for walls, but they have different ways to fill it out. Local governments (or companies) may submit their standard to the bSDD so that all bSDD-compatible BIM applications can look up the property and fill it out in a standardised way (such as picking for a list of preset possible values defined by the local government).

More reading:

  1. Swagger API docs

  2. bSDD Github Repository


Learning how to use the bSDD is best done by reading the official Swagger API docs.

client = Client()

# Get a list of "dictionary domains". For example, Uniclass (by the NBS organisation) might be one domain.

# For example, search the Netherland's Nlsfb2005 classification standard for all codes that apply to an IfcWall.
print(client.SearchListOpen("", RelatedIfcEntity="IfcWall"))

# Alternatively, search up a particular classification code.
data = client.Classification("")

# You may also apply default properties (if the classification system on
# the bSDD defines them) to your IFC element. For example, if a
# classification code is for a load bearing wall, it can automatically set
# the "LoadBearing" property to True for you.
apply_ifc_classification_properties(ifc_file, element, data["classificationProperties"])