## 4 Discussion  
The involvement of users is a crucial matter at each stage of the product development cycle, as it influences their contributions in an aggregate way and, thus, maximizes their effects [30]. Notably, it is recommended to involve users in the initial design stage, as it is a critical phase of the design process [31; 32]; increased access to and understanding of the users' needs, experiences, and expectations offers a deepening in the functionality, usability, and quality of future new products. Moreover, engaging users at various stages across all the phases of product development cycle (from ideation and development to launch) would allow industries to interpret users' needs efficaciously and to obtain solution-related knowledge [33; 34; 35]. As stated by [PERSON] et al., the user knowledge is crucial in the process of developing innovative products and in designing customized services, and virtual technologies can be the means to share such knowledge [36]. Through the successful implementation of digital technologies in the product design phase, user interaction, personalization, and product visualization are made possible, paving the way for meeting the dynamic needs of the user during product development [37]. According to [PERSON] and [PERSON] [31], design tools should simplify the communication between designers and final users in a \"co-design approach\", and this synergic collaboration between designers and users' favors user-centered design approaches to active co-design. From this view point, virtual reality is an interesting option, allowing the production of representations of the concept and the collection of data on ergonomics, usability, user acceptance, body metrics, and users' \begin{table}
\begin{tabular}{c c c} \hline \hline
**Sample User** & **Median** & **Group** \\ \hline
1 & 5 & Averagely activated \\ \hline
2 & 7 & Activated \\ \hline
3 & 5 & Averagely activated \\ \hline
5 & 4 & Averagely activated \\ \hline
6 & 4 & Averagely activated \\ \hline
7 & 2 & Deactivated \\ \hline
8 & 5 & Averagely activated \\ \hline
9 & 5 & Averagely activated \\ \hline
10 & 5 & Averagely activated \\
11 & 1 & Deactivated \\
12 & 6 & Activated \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Median computed on UES questionnaire scores and respective groups of engagement classification. Elements of the table highlighted by a box correspond to the participants for whom the UES method and the FER method gave the same response. feeling [38; 39]. VR is being widely employed in different domains of manufacturing such as design, prototyping, assembly, and maintenance [40] since it addresses all the requirements in each product development stage thanks to its capability of solving engineering design concerns of the manufacturer, logistical concerns of the maintainer, and training and programmatic concerns of the operator [41]. The involvement of potential users in both generation and development stages of an NPD (new product development) project might offer to producers the possibility of understanding and interpreting what users actually shared in the ideation stage, and to precisely apply the user knowledge to the design of the new product in the development stage, leading to a synergistic effect. In this context, the evaluation of the level of agreeableness felt by potential users of a product/service seems to be a crucial point in the success of a new product. Virtual technologies offer a valid approach to the initial phases of the product development cycle, in particular in the design stage. A virtual prototype would allow tailoring the new product/service to the customer based on a direct feedback from sample users; this way, it would be possible to correct and rethink the product, avoiding the costs of production of different physical prototypes. In addition to product development, virtual reality and virtual environments can be involved in the development of services targeted at the final users.