# Using Game Engines for Visuo-Haptic Learning Simulations
## 7 Conclusions and Future Work  
visuo-haptic interactive solutions have been proposed to develop and to enhance students' ability to learn by adding tactile or kinesthetic sensations to visual simulators. A common way to develop a visuo-haptic simulation considers the use of a graphic and physics-based engine orchestrated with a haptic rendering framework. Nevertheless, new powerful simulation tools such as game engines, provide also the opportunity of incorporating a higher level of visual realism to the simulations. \begin{table}
\begin{tabular}{l c} \hline \hline
**Question** & \(p\)**-Value** \\ \hline Q1 & 0.0002 \\ Q2 & 0.0002 \\ Q4 & 0.0020 \\ Q5 & 0.0106 \\ Q6 & 0.0106 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: \(p\)-value results obtained for each perception questionnaire question. Therefore, in this study an architecture to use game engines to create visuo-haptic interactive simulators is presented and tested. The incorporation of game engines capabilities allowed authors to facilitate the design and deployment of e-learning laboratories. Moreover, in this study a new successful technique to interconnect multiple haptic devices, even from different manufacturers, to the Unity platform is also described. In this context, a plugin named HaDIU was developed in this work in order to enable interconnectivity and functionality of multiple devices, as well as the generation of haptic rendering in game engines. While Unity is used to perform some of the physics calculations and graphic visualization, HaDIU is in charge of connecting haptic devices, sending their data to Unity, calculating interaction forces, and deploying force feedback on them. The proposed novel architecture successfully demonstrates the connectivity of multiple devices in game engines and, at the same time, that the performance of the application is not affected by the number of connected devices. The performance depends on the inherent physics of the rendered scene. A factory design pattern that facilitates the development of complex environments that make use of haptic feedback is described in this work. This is due to the instantiation of haptic interaction and ideal haptic interaction points' virtual objects. This behavior is kept during the use of multiple haptic devices, and allows developers to create more permissive interactive environments by letting them decide what type and how many devices they will use. The results obtained in this study state that our approach is functional, it enables the use of multiple haptic devices, and it incorporates game engines as visuo-haptic simulation frameworks. Several simulations were designed and implemented in this research to verify the operability of haptic devices, where each scenario was properly modelled with different haptic objectives. An experimental study was performed to validate that this approach provides better visualizations than an existing single purpose application. Engineering students enrolled in an introductory physics course compared the Unity Forces visuo-haptic simulator developed with the proposed architecture of this work with a similar visuo-haptic simulator developed by the standard procedure. By means of a perception questionnaire, students clearly stated that Unity Forces had both a better force feedback and a better graphic visualization. A study of CPU utilization showed that even when six haptic devices were connected simultaneously in the environment, force feedback generation and graphic rendering were displayed properly, and no discrepancies on performance consumption were present during their connectivity. These results proved that proper multiple haptic devices connectivity in game engines is achieved by using HaDIU. A comparison of development times to create visuo-haptic interactive simulators was also performed. The results clearly showed that developers can design visuo-haptic simulators faster when using HaDIU than using traditional techniques.