Pure Land Augmented Reality Edition

The Mogao Grottoes—also known as the Caves of the Thousand Buddhas—which these installations interpret, occupy a site at Dunhuang. A small oasis town in the desert of northwestern China, Dunhuang was a gateway to and from China on the ancient Silk Road, which carried trade between China, eastern and western Asia, and India from the fourth century BCE until the 14th century CE. These temple grottoes are not only a great art treasury but also an enduring record of globalization.

Dunhuang Academy’s Dunhuang Mogao Cave Paintings Digitization Project Plan focuses on the quest for a definitive model of preservation for this highly significant site, which is under extreme duress from climate change and human factors. Many believe that Dunhuang’s future lies in its digitization program, which is a cornerstone of new initiatives. Acquiring the images requires special cameras, custom-made railings on which these cameras can be moved, as well as ample computer processing power and trained staff (in 2012 there were 50 members of the photographic team). After the ceilings, walls, niches, and statuary have all been photographed as a complex mosaic, technicians then stitch the data together into finished ultra-high-resolution pictures. It takes up to three months for a team to image a single cave.

Mobile media technology was used to create an augmented reality rendition of Cave 220. In this installation, the walls of the exhibition room (which share the same scale as the real cave) are covered with one-to-one scale prints of Cave 220’s “wireframe” polygonal mesh—which provides users with visual cues as to what to explore. These derive from the Dunhuang Academy’s original “point cloud” laser scans of this cave. Inside a virtual model, the high-resolution photographs of the cave’s paintings and sculptures are digitally rendered onto this polygonal mesh to create the composite 3D representations that are then presented to the visitors on the tablets as they navigate the exhibition space. Tracking cameras track the position and orientation of the visitor tablets, while computers render the appropriate views of the digital cave, transmitted via Wi-Fi, in real-time. In doing so, the tablet screen shifts from being considered as an object in and of itself, to functioning as a mobile framing device for the staging of a “virtual” rendering of the real cave that relies on an intricate spatial tracking system. Cave 220 is being exactly mapped between real space and the digital model. In this instance, Pure Land AR is activated in the twists and turns of the hand-held screen.

By moving the monitor around the space, the viewer can examine three walls of the cave, and by holding the tablet aloft, he or she can also see the magnificent ceiling painting. Thus the tablet reveals the cave as something that is apparently located in the real space of the gallery. As the visitor/user entertains the various possibilities of moving through the space with the tablet, the changing views of the cave are fluidly and accurately shown on the screen. In this way the classic trope of a “window on the world” is virtually enacted.And given that this world is bounded by Cave 220’s walls, when the viewer brings that window into contact with the exhibition wall surface, its painting appears at exactly 1:1 scale within the frame of the tablet screen. The conjunction between the actual wireframe image on the exhibition walls and the life-like cave rendering seen on those walls via the tablet window operates in the borderline between the indexically real and the phantasmally virtual—between re-embodiment and dis-embodiment. Pure Land AR thus weaves a set of subtle paradoxes into its web of virtualization and actualization, and these paradoxes feed the kinesthetic excitement that is clearly evident in all visitors’ astonished enjoyment of this installation. It thus aligns with the technologies of telepresence that virtually transport the viewer between the present location and another place—in this case, from the exhibition space to Dunhuang.

Pure Land AR thus demonstrates the dynamics of a single-user, multi-spectator interface that is important to the notion of museums as places of socialization. A group of people will always surround the user, and will follow, direct, gesture, prompt, and photograph the user’s view of the world. This dynamic is integral to the interpretation, and to the performance of the work. The view that everyone should have his or her own tablet interface would deny the dynamic of this interchange and only advantage more isolated journeys of discovery.