## 6 Experimental Verification
### System Application  
The developed system was applied in the BIM platform for the construction management of steel structures. Figure 15 shows the interfaces of the progress management module, the detailed design module, and the quality management module of the BIM platform.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Model Type**} & \multirow{2}{*}{\begin{tabular}{c} **Geometry File** \\ **Size** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Geometry** \\ **Conversion** \\ **Time (s)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **FPS** \\ **FPS** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Memory** \\ **Footprint (MB)** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Drawcall** \\ **Times** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Redundancy** \\ **Elimination Rate** \\ \end{tabular} } \\ \hline Model 1 & 18.2 & 8.22 & 38 & 330.6 & 698 & 24,310/25,008 = 97.21\% \\ Model 2 & 57.9 & 29.57 & 29 & 568.4 & 2249 & 32,789/35,038 = 93.58\% \\ Model 3 & 57.8 & 28.00 & 33 & 517.5 & 1307 & 91,379/92,686 = 98.59\% \\ \hline \hline \end{tabular}
\end{table}
Table 2: Test results of the system performance using the approach of component redundancy removal.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Model Type**} & \multirow{2}{*}{\begin{tabular}{c} **Length of** \\ **Fold Edge** \\ **(mm)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Instances** \\ **Number** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Vertices** \\ **Simplification Rate** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Patches** \\ **Number** \\ \end{tabular} } \\ \hline Model 1 & 0 & 25,008 & — & 7,670,758 & — & 4,673,856 & — \\ Model 1 & 10 & 20,247 & 19.04\% & 3,017,113 & 60.67\% & 890,839 & 80.94\% \\ Model 2 & 10 & 35038 & 0.00\% & 11,648,350 & 41.66\% & 3,645,642 & 69.22\% \\ Model 50 & 20,488 & 41.53\% & 560,056 & 97.20\% & 141,657 & 98.80\% \\ \hline \hline \multirow{2}{*}{Model 3} & 0 & 92,686 & — & 19,171,744 & — & 11,554,938 & — \\ Model 3 & 10 & 59,889 & 35.39\% & 7,787,798 & 59.38\% & 2,521,562 & 78.18\% \\ Model 50 & 36,764 & 60.33\% & 817,754 & 95.73\% & 209,202 & 98.19\% \\ \hline \hline \end{tabular}
\end{table}
Table 3: Test results of system performance using LOD technology.  
Figure 15: BIM platform interfaces of (**a**) the progress management module, (**b**) the detailed design module, and (**c**) the quality management module.  
In the progress management module, components are displayed in different colors according to their progress status. For instance, green denotes installed components; red denotes delayed components; blue denotes produced components; and yellow denotes components stored in the warehouse. Progress information of components is integrated with the information extracted from the IFC files and displayed through the proposed visualization method. In the detailed design module, key parameters of components, such as weight, length, and location extracted from the IFC files, are shown and can also be edited. In the quality management module, the uploaded data integrated with IFC components are analyzed automatically, and the distribution of quality issues is illustrated by pie charts. The system application results show that the proposed algorithms and techniques can support the implementation of the BIM platform for steel structures.