Interaction on digital tables has been restricted to a single layer on the table's active work-surface. We extend the design space of digital tables by exploring multi-layer interaction techniques. Here the user can maintain multiple-layers of visual content and move between layers by moving their pen in the space between their body and the tabletop. This space is divided into multiple parallel-planes with each plane corresponding to a layer.

We created a sketching application that uses multiple-layers to create a rich and clutter free environment. The layer farthest from the work-surface consists of several piles that the designer browses in successive layers to select and edit an image in the layer closest to the tabletop. One problem with multi-layer techniques is maintaining the interaction to a fixed height above the physical surface without entering a different layer. To overcome this we devised a drift correction technique where the layer’s height is dynamically adjusted to maintain the cursor within a layer.