# Virtual Reality for Spatial Planning and Emergency Situations: Challenges and Solution Directions
## 5 Discussion
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & **Challenges** & **Solution Directions** \\ \hline \multirow{4}{*}{Application design} & & Starting first with the building model construction over assets (e.g., [16]); \\  & & Attention to the properties a model for a VR application should have (e.g., [26]); \\  & The 3D coordinate system of the modelling & Indicators for improving the participants’ perception of distances and depth should be represented; \\  & & Inported objects end up being invisible & Models’ geometry and spatial data should exactly represent the real environment (including recognizable objects); \\  & & Because they are inverted; \\  & & Z-fighting phenomenon. & \\  & & \\ \hline \multirow{4}{*}{User experience} & & Optimization requires an iterative process; \\  & & High rates of polygons or materials and \\  & & objects negatively affect rendering; \\  & & Discomfort (e.g., cybersickness) makes the \\  & & experience less immersive (e.g., [26]); \\  & & A high movement speed can cause motion \\  & & sickness and a lower speed can make the \\  & & experience boring and decrease the \\  & & participants’ tension [31]. \\  & & Creating balanced groups to compare different \\  & & circumstances (e.g., experience level, etc.) \\  & & & \\ \multirow{4}{*}{Collecting results} & & Ehtical approval, consent form that needs to be \\  & & signed that includes an explanation of \\  & & cybersickness that could potentially occur. \\  & & \\ \cline{2-3}  & & Selection of the questionnaire (e.g., usability, \\  & & presence or SSQ); \\  & & Three levels of metrics that are used for \\  & & evaluating wayfinding behavior: \\  & & decision-making, task performance and \\  & & observation behavior \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Overarching recommendations: Challenges and solution directions. What Roadmap/Recommendations Can Be Derived from the Scientific Literature When Designing and Developing a VR Application for the Evaluation of Emergency Routes? The technical challenges that occurred during the development phase discussed in the articles were grouped into three categories: the model, the game engine and VR. It should be emphasized that the majority of the challenges and solutions are especially suitable for researchers who are also not very experienced with developing VR applications. Other elements recognized concern the model conversion format, whereby the 3D building should be converted to a suitable format to avoid transition errors to avoid a loss of structure in the data, such as difficulties regarding units and the \(Z\)-axis. The importance of picking the correct import and export settings was implicitly mentioned by [26]. When a model is unpacked, its import settings can no longer be changed. Later in the process, this can result in problems with lighting settings and materials that are imported, which can both influence the usability of the application. One of the reasons the models were unpacked was to make objects interactable. This was especially the case for doors, which are important in indoor wayfinding studies. This potential problem was also mentioned by [26], which proves the relevance of this point for other researchers. In Table 4, the final recommendations for the use of VR for spatial planning and emergency situations are provided. Thus, in Table 4, an overview of the overarching recommendations is provided in a summary format. Concerning the proposition of a roadmap, a general approach for future application development can be derived from the findings. In Figure 4, we combine these findings into a framework as a guide for future VR application development for spatial planning and emergency situations. Figure 4 covers the stages of development as horizontal swim lanes, including creating the model, designing the environment (e.g., importing assets and game engine setup) and developing the user experience (e.g., using and testing the VR application).