The National BIM Library is a free online library consisting of generic and proprietary BIM objects such as walls, windows, doors, foundations, cladding, roofs in IFC format and formats for use in Autodesk Revit, Bentley, ArchiCAD, Vectorworks and Teckla.

The creation of these BIM objects in the National BIM Library in IFC format have been developed by using the xBIM toolkit as the main underlying technology.

Here is the step-by-step process of how the BIM objects were created using xBIM:

1. In order to keep data open, transparent and reusable by different parties involved in a collaborative construction project, there is a need to use an open & neutral format, hence the BIM objects have been created in the IFC format.
   
2. An intensive research is then done to collect parametric information, naming standards and content from industry experience and UK manufacturers as well as existing documentation.
3. These information is then entered into a spreadsheet.  This spreadsheet acts as the “database” that contains comprehensive information about each object, this sets up the basis for the IFC conversion process.
4. A user can then upload (“feed”) the spreadsheet into an in-house application called “xBIM National Building Library Converter”. The converter can convert the information on the spreadsheet into standard IFC files. This application uses The xBIM Toolkit as the underlying technology to map the information on the spreadsheet into appropriate IFC properties.  The xBIM Toolkit also performs validation checking to ensure all IFC files created complies to IFC2x3 (TC1) standards.
5. Apart from creating a standard IFC file, there is an option to create a Revit-specific IFC file (by selecting the “Save Revit groups information”).  Selecting this option will insert more information into the IFC file to allow grouping information to work in Revit, which is not mapped out as part of the standard IFC information sets. After the IFC file has been created, the  IFC file can be imported into Revit using the “xBIM Add-In for Revit” (another in-house developed program) which is installed onto the user’s machine and appears at the top of the toolbar in Autodesk Revit.
   
   
6. The IFC files for these BIM objects are then handed over to NBS for publication on their website, and are available free on the NBS National BIM Library.