## 4 Results  
### Preliminary Analysis  
In the experiment, each designer worked for approximately 54 h total. The data extracted from the log files were analyzed to evaluate the performance and collaborative behavior of each user, which can be related to the execution of commands from each sub-category in Table 1. In addition, the percentage of use of each contributory command executed was analyzed for all the designers in order to validate the Pareto principle. The intensity of commands executed by each designer can be considered a confounding indicator in this preliminary analysis since this measurement can alternately demonstrate high efficiency in the use of commands and/or greater experience in the use of the BIM software, or on the contrary, lack of knowledge or lower experience as evidenced by the execution of commands that provide little advance to the project. Therefore, higher performance cannot be inferred from this raw data, and further analysis is required in order to identify those commands actually contributing to the model. As can be seen in Table 2, while the total number of commands used by the architect was the highest, this designer also executed a great quantity of unnecessary commands, which were nearly all 'Cancel' (ESC key). In Autodesk Revit, a designer must use the ESC key twice to exit the current command, although on occasion users push this key more than twice, perhaps while thinking. Although this does not affect their performance, it must not be taken into account as productive work. Conversely, the mechanical designer executed the lowest number of commands, both total and unnecessary, which apparently could indicate a more efficient use of commands, but also lower performance. As was expected, the architectural designer also stands out with the highest number of geometrical modeling commands, which not only reflects the need to define the building's spaces and shape, but also the subsequent modifications to improve the design and resolve clashes between models. On the other hand, the plumbing designer executed the highest quantity of non-geometrical modeling commands. Through a deeper analysis of the specific commands executed by this specialist, it was detected that this was mainly due to the definition of numerous family types, creation of schedules, and inclusion of annotations in the model. The architectural and structural designers executed the highest number of collaborative commands, the former significantly more, which was also expected given that these two specialties provide most of the information that mechanical, electrical and plumbing (MEP) specialties require. In return, the three MEP designers supplied a similar amount of information that made it possible to detect and solve clashes between models. Regarding non-contributory commands, all the specialists executed a large amount of necessary commands. These auxiliary commands, such as those to modify the view configuration or temporarily \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Designer**} & \multirow{2}{*}{**Total**} & \multicolumn{3}{c}{**Contributory Commands**} & \multicolumn{3}{c}{**Non-Contributory Commands**} & \multirow{2}{*}{**Contributory**} \\ \cline{3-3} \cline{5-8}  & & **G** & **NG** & **C** & **N** & **U** & **B** & **Vs Backwards** \\ \hline Architectural & 9430 & 1770 & 169 & 372 & 3291 & 3228 & 657 & 2150 \\ Structural & 6433 & 1353 & 203 & 228 & 2470 & 920 & 1296 & 1425 \\ Mechanical & 5555 & 1032 & 121 & 141 & 2496 & 726 & 1039 & 1052 \\ Electrical & 6523 & 1296 & 165 & 184 & 2918 & 994 & 966 & 1401 \\ Plumbing & 7360 & 1190 & 366 & 165 & 3101 & 776 & 1762 & 1309 \\ \hline \hline \end{tabular}  
* G: Geometrical modeling: NG: Non-geometrical modeling; C: Collaborative; N: Necessary; U: Unnecessary; B: Backwards.  
\end{table} 
Table 2: Total number of commands executed by each designer. hide elements, are frequently needed to advance, but do not provide new information or elements to the model.