## 2 Methods
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Indicator** & **Evaluation Criteria** & **Low Level (1)** & **Medium Level (2)** & **High Level (3)** \\ \hline Tasks completed (TC) & Success rate or successful tasks & TC \(<\) 5 & 5 \(<\) TC \(<\) 10 & TC \(>\) 10 \\ \hline Time to complete tasks (T) & Total time to complete a design & T \(>\) 6 h & 2 h \(<\) T \(<\) 6 h & T \(<\) 2 h \\ \hline Dimensional accuracy (DA) & \begin{tabular}{c} Difference between model \\ dimensions and reality \\ \end{tabular} & \(p\) \(>\) 5 mm & 0 mm \(<\) \(p\) \(<\) 5 mm & \(p\) = 0 mm \\ \hline Interoperability (IO) & Number of applications used & IO = 0 & 1 \(<\) IO \(<\) 3 & IO \(>\) 3 \\ \hline Interactivity (IA) & \begin{tabular}{c} Ease of interacting with the system \\ (Likert scale) \\ \end{tabular} & IA \(<\) 3 & 3 \(<\) IA \(<\) 5 & IA \(=\) 5 \\ \hline Fatigue (F) & Continuous time without discomfort & E \(<\) 15 min & 15 min \(<\) E \(<\) 30 min & E \(>\) 30 min \\ \hline Human error (HE) & \begin{tabular}{c} Error rate per task or ratio of success \\ to errors \\ \end{tabular} & HE \(<\) 0.06 & 0.06 \(<\) HE \(<\) 0.12 & HE \(>\) 0.12 \\ \hline Learning curve (LC) & \
\begin{tabular}{c} Decrease in task completion time \\ between successive trials \\ \end{tabular} & LC \(<\) 1 min & 1 min \(<\) LC \(<\) 5 min & LC \(>\) 5 min \\ \hline Perceived creativity (C) &
\begin{tabular}{c} Number of different variants \\ produced \\ \end{tabular} & C \(<\) 4 & 4 \(<\) C \(<\) 10 & C \(>\) 10 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Indicators and evaluation criteria of Design Units. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Indicator** & **\(w\)** & **Shapes XR** & **Gravity Sketch** \\ \hline (a) Includes advanced tools & 10 & 70 & 100 \\ (b) Intuitive learning & 5.72 & 45.76 & 51.48 \\ (c) Visual quality of materials & 1.42 & 8.52 & 11.36 \\ (d) Exchangeable formats & 5.72 & 34.32 & 40.04 \\ (e) Collaborative tool & 8.57 & 68.56 & 68.56 \\ (f) File accessibility & 5.72 & 34.32 & 45.76 \\ (g) Creation of environments & 2.85 & 25.65 & 19.95 \\ Total & 40 & 287.13 & 337.15 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparative analysis for software selection. * Perceived creativity (C): The ability of the environment to facilitate the generation of diverse ideas during the design process. It should be noted that, unlike other indicators that can be obtained directly from simple quantitative measurements, human error (HE) represents a more complex dimension due to the multifactorial nature of human error. Therefore, a set of submetrics associated with task execution, interface interaction, and error management were identified. The final calculation of the HE indicator was carried out using Equation (1), based on principles of cognitive ergonomics and international standards for quality of use (ISO 9241-11 and ISO/IEC 25010), and aligned with previous studies in virtual reality and design engineering environments [76; 77]: \[HE=\frac{S}{S+F+R+I+L+\frac{T_{k}}{T_{i}}}\] (1) where
* \(S\) (successfully completed tasks): Number of tasks completed correctly without errors or interruptions. * \(F\) (failures or incomplete tasks): Number of errors or tasks that were not completed. * \(R\) (restarts): Number of restarts required due to loss of control or serious errors during the task. * \(I\) (interruptions): Number of interruptions caused by interface interaction difficulties. * \(L\) (loss of control): Number of times work control was lost, forcing task to be abandoned or redone. * \(T_{e}\) (error correction time): Total time spent correcting errors, including repetitions or adjustments needed to proceed. * \(T_{t}\) (total task time): Total time required to complete task, including errors, interruptions, and repetitions. After analysing the individual indicators, a weighted usability index (UI) was calculated for each dimension (effectiveness, efficiency, and satisfaction) using Equation (2).