## 4 Results  
The average modeling times employed for each participant in each of the parts in our study are shown in Figure 8. Except for Models 3 and 6, the time required to create a model using EVM was greater than the time required to perform the same task using SketchUp. For Model 6, both tools performed similarly. The boxplots corresponding to modeling each part are illustrated in Figure 8. The execution time for each participant is presented in Figure 9. Boxplots for execution times are displayed in Table 8.  
After confirming the normality of the data with a Shapiro-Wilk test and applying a repeated measures \(t\)-test with Bonferroni correction to compare the mean execution time for each model, we observed statistically significant differences between EVM and Trimble SketchUp except for Model 6, as detailed in Table 8.  
Regarding the SUS score results, the mean value of the SUS score using EVM was 92.3 points, with a standard deviation of 6.15, and 76.30 points for SketchUp, with a standard deviation of 6.69. A repeated measures \(t\)-test concluded that there existed a statistically significant difference between the SUS scores, \(t\) (22) = 8.89, \(p\) < 0.001, which confirmed the observation of the boxplot in Figure 10. \begin{table}
\begin{tabular}{c c c c c} \hline
**Q1** & **Q2** & **Q3** & **Q4** & **Q5** \\ \hline I would use this tool frequently & I find this tool & The tool was easy to use & I would need the help of somebody with technical knowledge of this tool & The tool’s functionality is well integrated \\ \hline
**Q6** & **Q7** & **Q8** & **Q9** & **Q10** \\ \hline The tool is inconsistent & Most people could learn how to use this tool very quickly & The tool is very difficult to use & I feel confident using this tool & I had to learn many things before I could use this tool \\ \hline \end{tabular}
\end{table} 
Table 6: System Usability Scale (SUS) questionnaire [41]. \begin{table}
\begin{tabular}{c c c c} \hline
**Q1** & **Q2** & **Q3** & **Q4** & **Q5** \\ \hline Navigating the command menus was not a problem for me. & Navigating the scene & Changing the scale of the scene was not a problem for me & Finding the command I was looking for was not a problem & Creating a 3D primitive was not a problem \\ \hline
**Q6** & **Q7** & **Q8** & **Q9** & **Q10** \\ \hline Drawing in 3D was not a problem for me & Deleting an object was not a problem for me & Editing an object was not a problem for me & Copying an object was not a problem for me & Undoing and redoing the last command was not a problem for me \\ \hline \end{tabular}
\end{table} 
Table 7: Ease of use questionnaire [44]. Figure 8: Boxplot for each modeling task using EVM and Trimble SketchUp. Figure 9: Times employed by the participants to create the six models using SketchUp and EVM. Considering the ease of use score, the mean value for the SUS score using EVM was 4.17 points, with a standard deviation of 0.19 and a median of 4.2. SketchUp obtained a mean value of 4.06 with a standard deviation of 0.43 and a median of 4. Because of the non-normality of the data, we applied a related-samples [PERSON] signed rank test, which revealed that there were no statistically significant differences between the ease of use scores (\(Z=-1.32\), \(p=0.18\)). The corresponding boxplot is presented in Figure 10.  
The relative SUS and ease of use scores for each participant (the ease of use score was normalized to a 100-point scale) are presented in Figure 11. The relative score was calculated by subtracting the SketchUp score from the EVM score. Positive values indicate better scores for EVM, and negative values refer to SketchUp. The rectangles represent the score distributions between first and third quartiles. The horizontal line inside the box represents the average score. The relative scores per question are shown in Figure 12.  
Figure 11 shows that all participants rated EVM higher than SketchUp in the SUS questionnaire except for one participant.