The OSVR HMD is a lower-cost, open-source, upgradable head-mounted display that offers an alternative to Oculus' closed platform and the expensive high-end system that Valve and HTC built.
The OSVR HMD is rather small compared to the Vive and Rift. The headset is only seven inches across at its widest point. The faceplate is 3.75 inches tall, but the cables come out of the top, adding to the total height. The HMD is also fairly shallow at four inches deep.
It may be small, but the OSVR HMD is rather heavy for its size. We found the Oculus Rift to be 470g, while the Vive weighs 563g. Meanwhile, the OSVR kit tips our scale at 650g, despite its size advantage.
Its front is made of glossy black plastic with the OSVR logo across the front. Infrared lights used for tracking are located behind the reflective faceplate. And inside, the OSVR HMD employs a 5.5-inch 1920x1080 low-persistence OLED display at 60Hz. That refresh rate is sub-optimal, but it operates at a simulated 240Hz, which OSVR says helps keep persistence of vision down on the screen.
The OSVR HDK 1.4 is designed to accommodate customization that enables additional functions. Removing the faceplate is a matter of simply loosening two screws on the bottom of the headset. OSVR has plans to release an upgraded faceplate that features a Leap Motion camera built in. And while there are currently no alternatives for the screen, the potential is there to swap in your own display. This capability isn't really meant for enthusiasts, but rather hardware developers who wish to iterate on their OSVR designs.
Oculus' Rift and HTC's Vive both use variations of Fresnel lenses to minimize weight. Fresnel lenses are typically much shallower, thus requiring less glass than typical lens designs. OSVR doesn’t follow suit, though. The kit uses a pair of lenses that are convex and bevel out towards your eyes instead (they are similar to fisheye lenses in appearance). We surmise that the lenses make up a large portion of the HMD's extra weight.
The OSVR HDK doesn’t offer any kind of IPD adjustment, but does include independent lens depth adjustments. On the bottom of the headset, you’ll find a knob that lets you dial in each lens' perfect location. But I found that I wasn’t able to adjust them very far before they both crashed into the bridge of my nose. People's faces come in a wide variety of shapes and sizes, so my case won't be universal. Still, it's clear that the lenses should be deeper into the HMD for many people.
The OSVR HMD's body is made of hard plastic with a matte black finish. Its top includes a loop for the headband and enough space to feed the data cables through. The right side of the headset includes a USB 3.0 port that can be used to power accessories.
The face cushion on the OSVR HMD is made of a pliable rubber material that allows the headset to conform to your face's shape. OSVR lines its face gasket with a removable foam liner, which is held on by Velcro similar to HTC's Vive. The foam that OSVR includes is very thin—only a few millimeters. There's not enough cushion to hold the HMD's substantial weight comfortably. I found myself longing for the Vive's thick foam. More cushion might have solved the issue of the lenses touching my nose, too.
The headset's weight is part of OSVR's problem. However, its head strap could also be improved upon. Think of the strap's soft, stretchy material as similar to what you might see on a pair of ski goggles. The top is made of thick nylon with Velcro over most of it. Oculus and HTC designed their straps to come down low on the back of your head, helping balance the HMDs during long gaming sessions. The OSVR HMD strap doesn't do this; it simply wraps around your head, distributing weight less evenly.
OSVR's data cable exits the top of the headset and passes over the upper strap. It runs through a small box holding the strap's three points together. As a result, the cable is naturally directed straight down from the headset. This cable is approximately three feet long and features a proprietary plug that connects to the belt box module.
Belt Box Module
All of today's VR platforms have their own way of dealing with the fact that you're tethered to your computer. Oculus streamlined its system down to one proprietary cable in time for retail availability, but the DK2 required far more cable management. OSVR's HDK 1.4 is still very much a developer kit, and the cable configuration shows as much with an arrangement similar to Oculus' Rift DK2. At least this headset manages to keep cables coming from it to a minimum. Beyond the belt box, connectivity gets much more confusing.
The HMD plugs into one side of the belt box. That cable is flanked by a microphone/headphone jack and an auxiliary USB 3.0 port. The other side of the belt box features HDMI, a USB 3.0 port, and the power jack. As its name suggests, the belt box is meant to clip to your belt or pants as you wear the headset. HTC's approach is similar, though it puts the link box on your desk instead of on your hip.
A wearable belt box helps relieve tugging pressure on the back of your head from hanging cables, though you're left dealing with half a dozen cables dangling from your side. This approach works, but it's still not what we'd call polished.
IR Positional Tracking Kit
The OSVR HDK 1.4 comes bundled with IR tracking to monitor your head's position in space. This feature is complemented by sensors inside the HMD to track the direction you're facing. The front panel features an array of infrared lights seen by the OSVR IR camera (if you remember, Oculus included a similar device with its Rift DK2). The camera that comes with the HDK 1.4 features a tiny lens, which we found to be somewhat of an issue. The headset has to be facing the camera for head tracking to work; it only has IR emitters inside the faceplate. There's nothing on the sides or rear. This limits the range you can rotate your head.
When the camera can no longer see the OSVR HDK clearly, your position inside VR starts moving around. Sometimes it drifts to one side, and sometimes it skips around a little bit. Tracking issues can lead to motion sickness if you haven't yet developed your "VR legs." We didn't have that specific problem, but the experience sure suffered for it.
Tracking issues seem to be intermittent, though. Sometimes the platform worked flawlessly, and other times (in the same game) we'd be all over the place. It's definitely important for the camera to have an unobstructed view of the headset, and its likely a good idea to avoid USB hubs. We noticed that our tracking woes were greatly reduced when the camera was plugged directly into our motherboard instead of the USB port on the side of our monitor.