GravityZone
Also known as GravityZone+, Gravity Zone
Instead of moving a cursor, the user tilts the joystick to pull every object in the scene toward themselves or push it away; objects that come closer than a threshold turn fully transparent, so the layers in front of a hidden target are peeled off, and the target is then selected with a ray.
How it works
All selectable objects are translated together along the user's view, so their positions and apparent sizes change but their relative layout does not. Unselectable objects are hidden during selection. In GravityZone+ the speed follows how far the joystick is tilted (Maslych et al. later used a squared, accelerating curve). Raycasting with the trigger selects. In Yu et al.'s first study (21 participants, Rift CV1) it was the fastest of seven techniques for low-complexity search and was ranked highest, but slowed down in dense scenes with many occlusion layers. In the second study (16 participants) GravityZone+ was slower than LassoGrid+ but faster than MagicBall+, with 5.96% errors.
Papers
- Difeng Yu, Qiushi Zhou, Joshua Newn, Tilman Dingler, Eduardo Velloso, Jorge Goncalves (2020). Fully-Occluded Target Selection in Virtual Reality. IEEE Transactions on Visualization and Computer Graphics doi:10.1109/tvcg.2020.3023606
- Mykola Maslych, Yahya Hmaiti, Ryan Ghamandi, Paige Leber, Ravi Kiran Kattoju, Jacob Belga, Joseph J. LaViola (2023). Toward Intuitive Acquisition of Occluded VR Objects Through an Interactive Disocclusion Mini-map. IEEE Conference on Virtual Reality and 3D User Interfaces (VR) doi:10.1109/VR55154.2023.00061