Retroreflectors are interesting materials, so known for their nature of reflecting light back to its source. Examples include street signs, bicycle reflectors, and cat’s eyes, which so hauntingly pierce the night. They’re also used in the Tilt Five tabletop AR system, for holographic gaming. [Adam McCombs] got his hands on a Tilt Five gameboard, and threw it under the microscope to see how it works.
[Adam] isn’t mucking around, fielding a focused ion beam microscope for the investigation. This scans a beam of galium metal ions across a sample for imaging. With the added kinetic energy of an ion beam versus a more typical electron beam, the sample under the microscope can be ablated as well as imaged. This allows [Adam] to very finally chip away at the surface of the retroreflector to see how it’s made.
The analysis reveals that the retroreflecting spheres are glass, coated in metal. They’re stuck to a surface with an adhesive, which coats the bottom of the spheres, and acts as an etch mask. The metal coating is then removed from the sphere’s surface sticking out above the adhesive layer. This allows light to enter through the transparent part of the sphere, and then bounce off the metal coating back to the source, creating a sheet covered in retroreflectors.
Tilt Five is an Augmented Reality (AR) system developed by Jeri Ellsworth and a group of other engineers that is aimed at tabletop gaming which is now up on Kickstarter. Though it appears to be a quite capable (and affordable at $299) system based on the Kickstarter campaign, the most remarkable thing about it is probably that it has its roots at Valve. Yes, the ones behind the Half Life games and the Steam games store.
Much of the history of the project has been covered by sites, such as this Verge article from 2013. Back then [Jeri Ellsworth] and [Rick Johnson] were working on project CastAR, which back then looked like a contraption glued onto the top of a pair of shades. When Valve chose to go with Virtual Reality instead of AR, project CastAR began its life outside of Valve, with Valve’s [Gabe] giving [Jeri] and [Rick] his blessing to do whatever they wanted with the project.
Six years later Tilt Five is the result of the work put in over those years. Looking more like a pair of protective glasses along with a wand controller that has an uncanny resemblance to a gas lighter for candles and BBQs, it promises a virtual world like one has never seen before. Courtesy of integrated HD projectors that are aimed at the retroreflective surface of the game board.
A big limitation of the system is also its primary marketing feature: by marketing it as for tabletop gaming, the fact that the system requires this game board as the projection surface means that the virtual world cannot exist outside the board, but for a tabetop game (like Dungeons and Dragons), that should hardly be an issue. As for the games themselves, they would run on an external system, with the signal piped into the AR system. Game support for the Tilt Five is still fairly limited, but more titles have been announced.