Physical Set-up

The physical set-up of the study is fairly simple, it involves a small stand, which the objects will be placed upon, a table and the Oculus Rift. The core issue of this set-up was matching the placement and size of virtual environment objects to that of the physical objects, such as the table. This issue needed to be handled effectively as the inaccurate representation of the environment could negatively effect participant presence and performance in the study, which would corrupt results. Three methods were considered to tackle this issue which would allow the physical set-up to mimic the virtual set-up.

The first method required the primary researcher to physically touch the boundaries of the table and the position of the stand for the objects, prior to the participant starting the study. When the boundaries and object positions are touched the controller position will be logged and the objects will be spawned in and correctly scaled. The main issue of this method relates to the control method the study uses, as discussed in the control method section of this thesis. This is

because the Leap Motion controller is attached to the Oculus Rift, meaning there is no static reference point in order to base the logged positions from. Additionally, as the Leap Motion is attached to the Oculus Rift HMD, the participants height and sitting positions would alter these positions. A further issue with this method is that the Leap Motion has no button or confirming gesture that could be performed when the physical position has been touched, unlike a controller such as the Oculus Touch controllers as a button could be pressed when the correct location is identified.

An alternative method involved the use of an Arduino and a multiple accelerometer gyroscope module. As with the previous method this required the primary researcher to set the locations up prior to the study being initiated. The Arduino would orientate the modules setting the initial position to zero, these modules would then be placed at the left and right boundaries of the table and in the ball stand position. The key advantage of this being that this set-up would only be required to be performed once per day. The main disadvantage of this method is the time required to create and verify that the system works accurately and reliably.

The final method considered required the study set-up to be permanently assembled in an area and the participant to perform the orientation action every study session. This method relied on the accurate modelling of the objects and table as these sizes would not change, only the location of the models would be altered. Two points would be marked on the table where the participant would place their hands, the location of the participants hands would then be logged and the virtual objects would be spawned around the participant using the hand location as a reference point. This method had many advantages as it could be achieved using the Leap Motion and with no additional hardware. Additionally, it would allow the environment to match each participants natural sitting position and height, removing any potential factors that could artificially affect presence.

After considering these methods of accurately replicating the physical environment it was decided to use the third method, utilising the Leap Motion. The main factor that lead to this decision was that the method used the selected control

method and wouldn’t involve any time consuming development. Whilst the method required each participant to perform the orientation task in order to spawn the virtual environment, this also meant that each study session would be tailored to the participant. In order to achieve this two raised points were attached to the physical table which the participant would be able to locate and place their thumbs on.

Figure 3.2: Image of the physical set-up of the study.

3.2.4.1 Virtual Environment

Like the physical set-up the virtual environment is simple, involving a model of a room, with a clock, board and table. No design considerations were made during the development of this environment, instead the development was guided by the design considerations discussed in the previous sections. The main aspect that the environment had to accommodate was the positioning of the virtual objects. In order to achieve this the virtual environment was split into two separate modules. The first module consisted of the room, clock and board models which would instruct participants. This would be centrally placed based on the position of the participants’ hands. The second module was simply made up of the table model with the ball stand, which would be positioned according

to the participants’ hands, ensuring that the ball stand would be directly in front of the participant, matching the physical environment. As the correct positioning of the room and table were the most important part of the implementation of this study it was decided to control the instantiation of the models with a keyboard button. This would be pressed when the principle investigator was satisfied with the participants’ hand placement, causing a fade to black and a fade into the environment to avoid any discomfort that would be felt from instantly changing location.

As participants had a strict time limit of thirty seconds for each object a clock was placed in front of the room which would countdown and reset every thirty seconds. Upon the expiration of each thirty seconds the current object would disappear and the next object would be placed on the stand. In addition to this, in order to keep the manual interference to a minimum, if the object was dropped and lost by the participant a new object would automatically be instantiated on the stand. The physical object would be taken from the participant and placed back in the physical stand.

Finally, as it was critically important to keep any interference from the principle investigator to a minimum a black board was placed in front of the room which would provide instructions to the participant. This would allow the participant to focus on the experience rather than having to hear an outside voice which would negatively affect presence scores.

Figure 3.3: Image showing the virtual environment for the study.