[3] Surface work has included customized solutions from vendors such as LM3LABS or GestureTek, Applied Minds for Northrop Grumman.
This is the most common form of surface computing in the commercial space as seen by products like Microsoft's PixelSense and iTable.
The aforementioned commercial products utilize a multi-touch LCD screen as a display, but other implementations use projectors.
Since the advent of tablet computing, a set of intuitive gestural interactions have been developed to complement two-dimensional surfaces.
[8] These everyday surfaces are often non-flat, so researchers have begun exploring curved and three-dimensional modes.
However, one of the main challenges is designing intuitive gestural actions to facilitate interaction with these non-flat surfaces.
A multi-viewpoint display would include any three-dimensional object surface like a sphere or cylinder that allows viewing from any angle.
[7] If a projection screen or a physical object surface is being used, a projector is needed to superimpose the image on the display.
However, a user will end up casting shadows onto the display itself, making it harder to identify high detail.
Such gestures allow the user to move in three dimensions of space without having to come into contact with the surface itself, such as the methods used in Depth perception.
[8] DepthTouch makes use of a depth-sensing camera, a projector, desktop computer, and a vertical screen for the user to interact with.
Instead of physically touching the screen, the user can manipulate the objects he or she sees displayed onto it by making freehand gestures in mid-air.