Marquardt, NicolaiJota, RicardoGreenberg, SaulJorge, Joaquim A.2009-04-292009-04-292009-04-29http://hdl.handle.net/1880/47104The advent of touch-sensitive and camera-based digital surfaces has spawned considerable development in two types of hand-based interaction techniques. In particular, people can interact: 1) directly on the surface via direct touch, or 2) above the surface via hand motions. While both types have value on their own, we believe much more potent interactions are achievable by unifying interaction techniques across this space. That is, the underlying system should treat this space as a continuum, where a person can naturally move from gestures over the surface to touches directly on it and back again. We illustrate by example, where we unify actions such as selecting, grabbing, moving, reaching, and lifting across this continuum of space.engsurfacestouchgesturesproximityGraphical user interfaces, design, human Factorstechnical report2009-925-0410.11575/PRISM/30775