Three Point Bend Experiment - Meta Quest VR .apk Program - University of Sheffield

A virtual "digital twin" experiment using Unity VR of the 3 Point Bend test delivered at the department of Multidisciplinary Engineering Education at the University of Sheffield.

This .apk file can be installed via the program SideQuest to any oculus quest headset and run.

In order to create a fully bespoke iVR experience it was decided that a game engine would be required in order to provide the truly immersive visual and interactive elements coupled with realistic simulations of physics. This decision was also coupled with a requirement to minimize VR hardware costs and enable an experience that is untethered (i.e. no cables linked to a PC). Based upon these considerations, the educational version of Unity 3D game engine (2020.3.34f1) was selected for use with Meta’s Quest 1 & 2 headsets. This software is free for academic use and the basic Quest headsets are low-cost consumer products.

The simulation geometry was created using educational versions of 3D CAD software (Solidworks, Fusion 360) based on the dimensions of the actual experimental apparatus. As photorealistic geometry was not the objective in this simulation, in order to help actively decouple fidelity effects (i.e. the students getting distracted by the 3d models themselves). The only part of the models that were modelled in realistic detail were the 3 point bending apparatus fixtures and beam samples; this was necessary to provide visual cues on operating the experiment and also facilitate experiential learning relevant to the practical experiment itself. This approach also reduced the overall computation expense in rendering the models, so the simulation could run at higher framerates, reducing likelihood of instances of cybersickness. The modeled geometry was exported to the free 3D modeling software Blender for further geometry optimisation (reduction of mesh complexity), followed by the addition of deflection animation (beam models only) and material texture baking. The finished 3D models were then exported in .GLTF format and then imported to the Unity Engine for use in the iVR simulation.

The Unity program was designed incorporating the free Oculus XR Plugin, to enable both controller and hand tracking interactions when transferred to the Quest headsets.

The same empirically derived coefficients of proportionality between force and deflection that were used in the Lo-Fi simulation were also used in this simulation to calculate the deflection for a given load applied to a sample. This deflection was displayed within a text box on the 3D model, and an appropriate movement of the jaws and distortion to the mesh of the beam was applied.

The user experience of the simulation is as follows once the program is loaded, the user is presented with a scale-correct simplified version of the three-point bending apparatus in an empty boundless space. Using the Oculus controllers or their hands, the users can pick up any sample to test and place it into the jaws of the test machine. It should be noted that this element was considered to be an important differentiator between the simulation types as high levels of interactivity have been previously shown to increase knowledge and skills acquisition. The force applied to the sample can be then adjusted using two large red interactable buttons and the amount of deflection read from the machine's virtual display. The beams deform according to the load placed upon them. The deflection is approximated visually, however, the deflection data given is accurate based on empirical data.