Current virtual reality (VR) systems limit users to a single virtual 3D environment (VE) at a time, which restricts their ability to engage with multiple VEs simultaneously. We present SLIVR, a VR-Hub designed to enhance multitasking capabilities by arranging multiple VEs in a regular polygon formation around the user. Each VE is visually represented by life-sized 2D previews that facilitate hub-based interactions. Direct Selection enables users to select objects within a VE directly from the preview, allowing them to remain within the hub. Additionally, Focus-mode enlarges a chosen 2D preview, providing access to objects beyond the initial viewport. In a user study ($\mathrm{N}=18$), we evaluated SLIVR against a conventional grid-based VR app launcher and a hub that utilized SLIVR's visualization but only supported Teleportation interactions. Our findings revealed that SLIVR improved target selection performance by 16.8% overall and by 30.5% when engaging with six VEs, compared to the grid-based app launcher. Notably, hub-based interactions accounted for 94.9% of selections, with Focus-mode being utilized six times more frequently than Teleportation.

This demo explores prioritization techniques to arrange see-through masks in virtual reality (VR). The oval masks show live previews of different virtual environments (VEs) and allow for seamless teleportation into a corresponding VE by putting the mask on the face. Each environment includes a mini-game (e.g., basketball and archery) in which the user has to perform a small task. The arrangement of the masks changes depending on a calculated rating, which considers the time since the game was last played and the game score. We envision this system to help users to multitask in VR. For example, to control multiple characters in VR games, to experience multi-strand (nonlinear) narratives, and to supervise semi-autonomous agents in different VEs.