## 3 Results
### Parametric Models of Typical Systems and Their Components  
From the photographic survey, twenty-two buildings were selected for detailed interior and exterior surveys using a Faro Focus x130 3D Laser scanner (Figure 5). The buildings were selected using a number of criteria to reflect representatively geographic location, scale, material, level of conservation and design paradigms as far as was practicable. Figure 4: Gradient-weighted Class Activation Maps (Grad-CAM) of ventilation grilles. Using the point cloud and pictures, 3D parametric models were constructed manually in REVIT(tm) accurate enough for an as-built verification and comparative analysis of three libraries. Models of vaulted ceilings at Possil Park in Glasgow, Loughborough and Middlesbrough libraries were made  
Figure 5: Laser scanned libraries. as exemplars at different scales. Middlesbrough Library is the largest Carnegie Library in the UK after Edinburgh Central Library. Its first-floor reading room measures 253.38 sqm and has an apex ceiling height of 8.73 m. It is possible to identify the ribs of the vaulted ceiling structure, the dormer windows between them together with the central ventilating grilles and recognise a prime example of standardised design with respect to ventilation. In Possil Park Library there are two reading rooms with vaulted ceilings of different sizes. The main reading room area is 142.38 sqm and curved ceiling height of 6.44 m. The second room is smaller in size which area measures 62.81 sqm and curved ceiling height of 4.06 m. The functional role of most cast plaster barrel vaults in these case studies is concealed by their decoration. Their ornate plaster mouldings and panels are also used to frame mechanical components such as skylights and ventilators. The task of identification in the variety of these decorative profiles is best directed straight back to the manufacturers' catalogues. Yet this is much easier than seeking to identify a bespoke profile as the number of manufacturers of cast plaster elements was relatively limited. It was the span and overall arrangement of the vault that might alter from building to building and so is the key parametric object. To date, REVIT(tm) family editor does not allow the direct importation of a point cloud. Two options for importing data were used. Firstly, using 'in-place' family mode, building the geometry relative to the point cloud with reference planes and parameters, then pasting geometry out to a true family before completion. Secondly, creating views or sections with dimensions exported as images. Images in family editor are then the basis to build the geometry which needs a scale added. Since REVIT(tm) does not allow the creation of custom shapes with the Ceiling tool, one option is to use a simple extruded \"Roof\" command, placing a component using the barrel vault as a host with \"families\" category \"roof\" selected. The other option is to create an in-place family. Using this technique, a ceiling family object created will now be read by REVIT(tm) as a ceiling, making it possible to associate ceiling-based components with it. For simplification and consistency in the creation of such families, these decorations are therefore better modelled in the same family so that they move with the host elements and can also be tweaked directly within the family parameters. Although without the external data the modelling is limited to the internal aspect of the components, it is not possible to get accurate information related to the components such as thickness of roof construction, skylight frames and so forth, it is possible with the benefit of archival research into building products and practices of the time to provide access to a more limited range of probable arrangements of the superstructure (Figure 6).