# HBIM: Background, Current Trends, and Future Prospects
## 5 Applications and Data Management
### Common Data Requirements
#### 5.1.2 Non-Geometric Data  
The need to include heritage-specific information unique to each individual asset is what truly sets HBIM apart from conventional BIM. Although the incorporation of non-graphical information is also essential in BIM models for contemporary structures, the unique characteristics of historical structures make this aspect particularly relevant and complex. Historic buildings derive their value from a range of historical, architectural, and artistic features that make them unique, and these must be included in a comprehensive HBIM model. These characteristics are often qualitative and generally difficult to standardize, as many of them are specific to each particular building. While the Nara Document on Authenticity of the UNESCO [71] emphasizes that avoiding the imposition of mechanical formulas and standardized processes is crucial to preserving cultural and heritage diversity, this lack of standardization presents a significant challenge for the creation of HBIM models and associated tools. Since incorporating non-parametric data is not typically a native feature of BIM, the common approach to including qualitative information is to develop an external database that can be linked to the HBIM model, with only a few cases directly embedding intangible data, such as descriptions and images, associated with specific objects. Regardless, information transfer between models remains a challenge due to the lack of a standardized vocabulary. Several authors [72; 73; 51; 74; 75] have proposed the adoption of standardized ontologies commonly used in cultural heritage data exchange, such as the one defined in ISO 21127 [76] (based on the CIDOC-CMR or Conceptual Reference Model of the International Committee for Documentation). Some examples demonstrate how well-defined semantics can be integrated with common metadata formats [77; 78]. While CIDOC-CMR excels at clarifying instances of semantic complexity, its focus on empirical data limits its effectiveness in describing family relations, rights, and intellectual processes [79]. An example of ontology for cultural heritage elements is shown in Figure 6.  
Another major challenge associated with historical data is the difficulty of acquisition. Unlike the relative ease of gathering geometric data, historical information often comes with considerable uncertainties and requires extensive documentation work to ensure its reliability. Consulting experts in the field [80] or analyzing texts (e.g., building standards) from the same period as the building or from structures with similar characteristics (e.g., age, location, structural type, materials, and use) [47; 81] can help fill gaps in the available historical documentation regarding the asset itself. However, in many cases, historical data are not required. As HBIM models transitioned from being merely a geometry with a historical database for the asset to becoming a tool for its management and preservation, it became essential to incorporate information about the condition of various building components, in particular, the structure, due to its crucial role for the stability of the building. These data can be quantitative, such as the value of specific material properties, by the definition of some kind of damage index for the whole structure or for some areas, or qualitative, as a mere description of the condition of the building's components. Accurate data on the building's condition and structural properties must be gathered through on-site inspections and tests. While qualitative assessments can be provided by experts during site visits, other essential quantitative information, such as material properties or internal defects, must be directly measured. In the case of CH structures, invasive, destructive testing is often impractical, making nondestructive testing (NDT) techniques an ideal alternative [82].