## 5 Discussion  
This study analyses the actual potential of immersive technologies in the specific context of industrial product design. Through an embedded single case study, the capacity of VR, AR, and MR was assessed in terms of transforming traditional workflows, enhancing creativity, and facilitating design validation. The empirical approach made it possible to verify the advantages and challenges of using immersive tools. The study examined the efficiency and effectiveness of these tools and also evaluated designer satisfaction in terms of their impact on the user experience. The results obtained confirm that the use of immersive technology helps streamline and improve the industrial design process. According to several previous studies, it has been found that these technologies have a great capacity to integrate into design workflows from the early stages to faciliate (1) ideation and concept generation [2, 31, 50, 102, 103]; (2) validation and visualisation of product designs in real contexts [34, 78, 104, 105]; (3) interactivity in the design process [1, 18, 28, 34]; (4) reduction in the learning curve [18, 19, 105]; (5) reduction in the time to complete tasks [1, 18]. Specifically, within the **conceptual design** stage, especially for the **inspiration** phase, VR enables the creation of spatial Moodboards. Designers immerse themselves in virtual environments where the generation of ideas is stimulated and creative activities are facilitated. By presenting information in a highly realistic way, these immersive spaces promote creative insights that are difficult to achieve with traditional media. Thanks to immersive 3D sketching, the limitations of two-dimensional surfaces such as paper or screens are eliminated. Immersive sketching tools allow drawing directly in three-dimensional space through natural gestures. This turns **ideation** into a fluid, fast, and flexible process, serving as a transition between early sketches and detailed 3D models. During the **detailed design** stage, immersive technologies are fundamental for generating prototypes and interactive virtual models. **Virtual prototypes** can be iterated quickly after simulations and analysis of results, reducing the costs and time associated with the production of physical prototypes. Regarding immersive **3D modelling**, it allows the creation of parametric and mesh-based geometric representations. In addition, the different peripherals facilitate the manipulation of 3D shapes (controllers, haptic gloves, or gesture actions with hands and arms). In the **validation** phase, they facilitate the simulation and evaluation of user-product interaction through virtual usability tests and ergonomic \begin{table}
\begin{tabular}{c c c c} \hline  & **Effectiveness** & **Efficiency** & **Satisfaction** \\ \hline \%RSD **S1/S2** & 12.61 & 12.32 & 10.86 \\ \hline \%RSD **S1/S3** & 22.4 & 19.95 & 21.45 \\ \hline
**RMSE **S1/S2** & 0.2 & 0.19 & 0.17 \\ \hline
**RMSE **S1/S3** & 0.35 & 0.31 & 0.33 \\ \hline \end{tabular}
\end{table} 
Table 7: Sensitivity analysis results. evaluations. The combination of VR with 3D printing, as **mixed prototyping**, facilitates the interaction of the design team with design solutions, evaluating their suitability for the context of use. Specifically, AR facilitates the validation of 3D models directly superimposed on the real physical environment, allowing real-time adjustment of geometries, dimensions, proportions, and positions. Finally, in the phase of communication with the client, immersive technologies provide an intuitive and high-quality **3D visualisation** of products, showing results at **full scale**, with the goal of facilitating the understanding of dimensions, proportions, and aesthetic and functional aspects from **multiple perspectives**, enabling walking around or through the product and facilitating early detection of errors or the need for changes. This spatial experience is especially interesting in the design of large or structurally complex products.