# Augmenting Industrial Control Rooms with Multimodal Collaborative Interaction Techniques
## 4 The Study
### Discussion  
The scatterplot application for the evaluation showed only a basic visualization, but the user feedback indicates that data exploration is a potential purpose for the HoloLens. The feedback we received regarding the cubes is reasonable as the scatterplot can become too large for the field of view of the HoloLens device. An alternative way to provide transformational controls would be to implement them in a special hand menu. Adding edge-bound controls could overlap with controls for additional functions we had in mind. We did not add them to the evaluation to keep the experiment simple. The readability of text on the HoloLens is due to technical limitations. The resolution of the display is only 1920 \(\times\) 1080 and, when moving away from virtual object,s they become smaller and are reduced in pixel count due to their size. A possible workaround until technical limitations are lifted by more advanced platforms could be to scale font size to some degree with distance to the user. As already mentioned, we had interactive functions in mind when developing the application originally. For example, we thought about giving the user the possibility to reduce the amount of data viewed by drawing a three-dimensional cube. We discarded the idea in favor of a simpler experiment, but such functions could further immerse the experience for the user. Our application shows only the minimal and maximal values. Further research could try to create a grid for MR-systems. Regarding RQ 1, we recognize the potential of MR-systems for data exploration. Further research could try to introduce a more immersive experience by adding functions to manipulate the visualization or evaluate other diagram types. With respect to the evaluation of different menu types, the technical problems need to be considered when interpreting the results. As mentioned, while we had problems with the rotating cube menu, most participants still thought three-dimensional objects could be interesting in user-interface design. The mixed results of the evaluation showed all types can be viable. To improve user satisfaction as much as possible, integrating user feedback into the development as early is recommendable. Regarding RQ 2, we can say that none element is superior to the other. Further research could try to integrate different elements with each other and create templates for standard scenarios. In general, a multimodal environment supporting a personalized way of interaction is helpful, e.g., by using dedicated interaction or structure models in the software architecture [9; 33]. The results for the collaborative application suggest a limited use of the visual cues of the MR-user for a collaborative task. Moreover, solving this task was reported by many participants to be much easier without the interaction of the HoloLens user. The collaboration with the HoloLens user seemed to be more effective by taking an observing stance, only using voice chat to instruct the desktop user. Showing the movement of the desktop user's mouse seems to be a helpful feature. Especially for a task that is accomplished on the 2D plane, the desktop mouse is a very effective tool. Based on this assessment, RQ 3 can be answered as follows: Visual cues of eyes and hands did not significantly improve the experience of collaboration for the planning task. Aside from general usability issues connected to the abilities of the HoloLens 2 itself, there were two main reasons for this: (1) The planning task can be handled much easier from a screen-based device, specifically with a mouse. This makes intervention from the HoloLens less relevant besides voice suggestions. (2) To make good use of the hand visualization, near interaction with the elements is needed. This comes with the trade-off of having to make bigger hand movements and/or decreasing the size of the interaction elements.