The aim of this study was to evaluate the principle "Brek Free", in particular the part "Break free from traditional 2D designs and implement interfaces into the 3D space". This study aimed to prove that embedding a 3D interface and a 3D interaction to completing a task in a virtual world will result in an improved UX, compared to embedding a 2D interface/interaction for the same task. Therefore a VR prototype, consisting of four different scenes, was developed: One scene where the landscape's color can be changed by pressing buttons and navigating through a traditional menu structure (2D); one scene with which the user could change the landscape color by hitting it with soap-bubbles; one training scene that includes the different interactive elements; one exploration scene that embeds both interfaces simultaneously.
Altogether 22 subjects were tested in a 2x2 factorial design. The factor 'Condition' (2D, 3D) was tested within-subject; the factor 'Sequence' varied between subjects. Yet, the latter was mainly used as a controlling mechanism. Each participant run four VR sessions: At first, in a training phase, the subject could explore the different interactive elements and make himself/herself familiar with the virtual environment. Then the subject received the task to color the landscape according to a picture that was shown beforehand. The coloring task was performed in two sessions, one using the 2D interface, the other using the 3D interface. Finally, in an open exploration phase, the subject could explore both interfaces simultaneously and without a given task. In between the tasks each subject was asked to fill out questionnaires: the Affect Grid as a pleasure and arousal scale after each VR session, the meCUE, as a general UX scale, and the IPQ as a presence scale. Time für each task was constantly recorded. In the exploration phase it was recorded which interface the subject chose first.
The results show significant differences in the mean values of the arousal scale between the 2D (lower) and 3D (higher) interfaces, as well as a stronger feeling of being present when using the 3D inteface, compared to using the 2D interface. Yet, making assumptions about an improved UX is hampered by signifficant usability differences between the two different interfaces. Regarding these results it is recommended to pre-test VR prototypes for usability issues before scaling the UX in a two-factorial design. However, the free exploration phase revealed that around 80% of the subjects chose the 3D interface as their primary interaction and spent signifficantly more time with it exploring. This leaves the assumption, that 3D interfaces, compared to their 2D counterparts, require learning and exploration and may be more difficult to master (and thus less efficient), yet subjects seem to accept the drawbacks nevertheless.
This Unity project allows the user to color the virtual landscape by using two different interfaces: Floating tiles (2D) and floating soap bubbles (3D). Leap Motion required.