An Open Testbed for Mixed Reality Precise Rotation Guidance: Comparative case study of Arrow, Gestalt and Magnifier Cues

A wide range of tools, machines from diverse industries are operated by the precise rotation of physical devices (e.g., knobs, encoders). Literature proved that Mixed Reality can provide rotation guidance by superimposing digital cues onto the real environment. However, existing studies primarily focus on speed rather than precision and lack proven solutions with standard comparison methods. We presented a novel open MR testbed to evaluate MR rotation guidance cue designs. It comprises (i) a 3D-printed structure with a controller mount for MR cue tracking, (ii) an industrial encoder (resolution 1.8º), (iii) an Esp32 microcontroller, (iv) a firmware for USB connection, and (v) a USB foot pedal to confirm rotation, (vi) test software and documentation. The testbed uses available off-the-shelf components, and it is distributed with an open source license, Unity package with cues examples and scripts for running tests with randomized targets and collecting performance data (error count and speed). We evaluated the MR testbed by comparing the Arrow cue (baseline) and two novel designs: Magnifier with a zoomed region and Gestalt leveraging related perception principles. A within-subjects study (N=36,180′′,18 ọ, M=27.58,±3.55) showed that the Magnifier is the most precise (p<.001), while the Gestalt is the fastest (p<.001). Moreover, males (higher motor and gaming skills) (p<.002,t=3.89) resulted in faster (r=−0.458,p<. 005). Participants who declared with higher gaming skills demonstrated less task load during the experiment (r=+0.548,p<.005). Overall, the participants slightly preferred the Gestalt (18) over the Magnifier (15), while the Arrow was selected by a few (3). Ultimately, the testbed has proven to be an effective research and evaluation platform for future mixed reality interfaces.