## 5 Results
### Outcomes of BIM2 IndiLight  
In total, 454 properties were defined across the task groups. During a subsequent comparison, 26 instances of property overlap were identified. These overlaps occurred when different packages representing the same information within the model, with naming conventions and supplementary details either identical or slightly varied. To resolve these overlaps, task group representatives convened to harmonize properties and prevent duplication (Table 2). As a result, 428 properties remain necessary for the DALEC simulation tool and for describing model components related to daylight and shading systems, lamps, luminaires, and user-specific lighting controls. Existing IFC properties were examined and aligned with these new properties wherever they conveyed similar information. As shown in Table 3, roughly one-third of the DALEC properties correspond to IFC2x3 properties,providing a solid foundation for early design stages that primarily involve basic model content covered by IFC. However, the correspondence of properties for artificial lighting and daylight components was significantly lower. The ZVEI BIM group is actively working on the standardization of artificial lighting components, and only \(\sim\)10% of the daylight properties and 2% of the sensor/control properties match IFC2x3. This discrepancy arises because these properties are more detailed and do not directly align with the IFC standards. In summary, the IFC2x3 does not provide an adequate database for accurate component descriptions or effective energy simulations and lighting designs. Table 3 presents the results by sector. While the ZVEI group has standardized artificial lighting properties for ONR CEN/TS 17623, over one-third of the DALEC properties derive from standards, with the remaining sourced from additional documentation or specific research. For daylight components, nearly half of the properties originate from standards and are further supplemented by component datasheets. Although sensor and control properties in building models lack full standardization, approximately 72% are defined by existing standards and guidelines. The LOIN is a framework that outlines the scope and level of detail for information to be exchanged. According to EN 17412-1 [28], LOIN should encompass a combination of geometric information, alphanumeric data, and documentation. When defining LOIN, \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multicolumn{2}{c}{**In Total**} & \multicolumn{3}{c}{**Property Package’s Overlaps**} \\ \hline  & \multicolumn{2}{c}{**PP1—DALEC**} & \multicolumn{2}{c}{**PP2—Artificial Light**} & \multicolumn{2}{c}{**PP3—Daylight**} & \multicolumn{2}{c}{**PP4—Sensor and Control Properties**} \\ \hline PP1—DALEC & 71 & & 4 & 6 & \(10\) \\ \hline PP2—Artificial Light & 114 & 4 & & 5 & \(1\) \\ \hline PP3—Daylight & 166 & 6 & 5 & & 0 \\ \hline PP4—Sensor and controlling properties & 103 & 10 & 1 & 0 & \\ \hline
**In Total** & **454** & & & & **428** \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Property lists and their overlaps. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multicolumn{2}{c}{**In Total**} & \multicolumn{2}{c}{**IFC—Properties**} & \multicolumn{2}{c}{**Documentation/Source**} \\ \hline  & & & **Standards and Guidelines** & \multicolumn{2}{c}{**Further Documentation—BIM2 IndiLight-Specific**} \\ \hline PP1—DALEC & 71 & 23 & **32\%** & 26 & **37\%** & 45 \\ \hline PP2—Artificial Light & 114 & 26 & **23\%** & 114 & **100\%** & - \\ \hline PP3—Daylight & 166 & 17 & **10\%** & 76 & **46\%** & 90 \\ \hline PP4—Sensor and controlling properties & 103 & 2 & **2\%** & 74 & **72\%** & 17 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Source analysis for each task group’s property package. a distinction is made between geometric and alphanumeric data. As shown in Table 4, each package primarily focuses on alphanumeric information, underscoring that a purely geometric representation of a building model offers limited value for simulation purposes.