The launch of the first consumer-focused VR headsets has researchers and 3D content developers focusing on the nausea issues that arise with head-mounted displays. The Oculus Rift and HTC Vive can make users feel immersed and comfortable in their virtual worlds, but that's easier in limited virtual environments, especially ones without movement. What can be done about the pukey feeling brought on by harsher forms of virtual movement, when the brain and the body don't agree on what's happening?

While some people recommend adding a fixed focal point to a VR world, like a cockpit or a peripherally visible nose, a group of Columbia researchers decided to test an idea that was patented years before the current VR boom: a dynamically shifting field of view [FOV]. The system works by recognizing rapid artificial movement during a seated VR experience—like when users press a joystick to rotate their first-person view, or when elevation rapidly changes thanks to objects such as stairs—and then gradually blacking out the peripheral edges of a VR headset's lenses until that upsetting movement dissipates.

In its report, which was published last week alongside a demonstration video (shown below), the Columbia team concluded that "even though we had a relatively small number of participants [24 after removing people who were considered "immune" to virtual motion sickness], our data indicates that FOV restrictors helped participants stay in the virtual environment longer and feel more comfortable than they did in the control condition." Users largely didn't notice the dynamic FOV changes until they were informed well after the study concluded, and the few who did notice reported preferring the limits, since they didn't obscure the primary VR viewpoint. Worth noting, this study's results included unanimous praise from its limited test audience, compared to mixed opinions on the aforementioned VR-nose study.

Rotation plus momentum minus periphery equals comfort

What's more, Columbia's researchers spelled out their exact method of both how much FOV they blocked out and the scale and speed at which the dynamic adjustment played out. Before the primary study was completed, the researchers asked peers to test out various FOV blockers and shaders until the team decided upon a blurred radius that started blacking visual data out at the 120-degree mark and stopped doing so at the 50-degree mark. Then they came up with a formula that accounted for rotation speed and forward momentum in determining exactly how quickly the FOV blocker would animate into view; if a user spun wildly or move forward rapidly, the view would block out faster, while staying totally still would cause the headset's default FOV to come back into focus at a barely noticeable rate.

While the US military had patented a similar system in 2014—specifically, one that targeted VR sickness in headsets worn on the face—that patent was granted with biometric sensors in mind. The Columbia study better resembles work already in progress by a Ubisoft game development studio, which is putting the finishing touches on its thrilling and surprisingly comfortable flight-action game Eagle Flight, coming to the Oculus Rift later this year. That game, which Ars has tested at multiple expos in 2016, noticeably restricts users' FOV when the game's first-person eagle character rapidly turns and dives in mid-air, but the game's action is still clearly visible, and the reduction in nausea is quite effective. (I consider myself Ars' nausea canary in the VR coal mine, and I was taken aback by that game's success.)

The Columbia authors note that more research should be done to determine what other tweaks might making its FOV restrictor even more efficient, including altering various texture shapes and shades along with perhaps integrating biometric data (à la the US military's patent). Any such research would be wise to take into consideration another recent development from a Microsoft research team: a grid of lights that creates the illusion of peripheral content without widening a VR headset's screens. Those studies may run nicely in parallel, as Columbia's research indicates that a larger VR screen could increase sickness; perhaps a subtler presence of light and color, as in Microsoft's test solution, could be the best of all possible worlds when it comes to broadening a sense of "VR presence" without adding any nausea.

2016 IEEE Symposium on 3D User Interfaces, 2016. DOI: 10.1109/3DUI.2016.7460053 (About DOIs).