Object and ARM shadows: visual feedback for cross device transfer.

Rekimoto's Pick-and-Drop (PND) cross-device transfer technique is commonly used to support multi-surface object transfer, for instance, between a multi-touch tabletop and tablet, due to its easily understood metaphor that emulates object movement in the physical world. Current multi-surface implementations of PND provide little to no feedback during the transfer process, creating confusion during transfer. This paper investigates two visual feedback techniques, Object Shadow (OS) and Object-plus-Arm Shadow (O+AS), designed to address this issue by visually representing the transferred object and its "owning" user during the transfer process.