3D virtual world program Second Life. 21st century The 2000s were a period of relative public and investment indifference to commercially available VR technologies. In 2001, SAS Cube (SAS3) became the first PC-based cubic room, developed by Z-A Production (Maurice Benayoun, David Nahon), Barco, and Clarté. It was installed in Laval, France. The SAS library gave birth to Virtools VRPack. In 2007, Google introduced Street View, a service that shows panoramic views of an increasing number of worldwide positions such as roads, indoor buildings and rural areas. It also features a stereoscopic 3D mode, introduced in 2010. 2010–present In 2010, Palmer Luckey designed the first prototype of the Oculus Rift. This prototype, built on a shell of another virtual reality headset, was only capable of rotational tracking. However, it boasted a 90-degree field of vision that was previously unseen in the consumer market at the time. Luckey eliminated distortion issues arising from the type of lens used to create the wide field of vision using software that pre-distorted the rendered image in real-time. This initial design would later serve as a basis from which the later designs came. In 2012, the Rift is presented for the first time at the E3 video game trade show by Carmack. In 2014, Facebook purchased Oculus VR for what at the time was stated as $2 billion but later revealed that the more accurate figure was $3 billion. This purchase occurred after the first development kits ordered through Oculus' 2012 Kickstarter had shipped in 2013 but before the shipping of their second development kits in 2014. ZeniMax, Carmack's former employer, sued Oculus and Facebook for taking company secrets to Facebook; the verdict was in favour of ZeniMax, settled out of court later. In 2013, Valve discovered and freely shared the breakthrough of low-persistence displays which make lag-free and smear-free display of VR content possible. This was adopted by Oculus and was used in all their future headsets. In early 2014, Valve showed off their SteamSight prototype, the precursor to both consumer headsets released in 2016. It shared major features with the consumer headsets including separate 1K displays per eye, low persistence, positional tracking over a large area, and fresnel lenses. HTC and Valve announced the virtual reality headset HTC Vive and controllers in 2015. The set included tracking technology called Lighthouse, which utilized wall-mounted "base stations" for positional tracking using infrared light. In 2014,