Since the very first reported arrival of the Oculus Rift developer kit on March 27th, units are trickling out to developers around the world. Two folks that I follow closely got their hands on a Rift to examine and both happen to be experts in their particular fields. They’ve posted their first early Oculus Rift review of the dev kit and both accounts are well worth a read.
Virtual Reality Researcher, Oliver Kreylos’ Early Oculus Rift Review
Oliver Kreylos is a PhD virtual reality researcher who works at the Institute for Data Analysis and Visualization, and the W.M. Keck Center for Active Visualization at the University of California, Davis. He maintains a blog on his VR research at Doc-Ok.org, where a few months back he showed us what it’s like to be inside of a CAVE.
Kreylos approaches the Oculus Rift as someone who has spent significant time with several head mounted displays and other virtual reality systems. He got to play with the Rift through a friend and says that he’ll “hold back a thorough evaluation until I get the Rift supported natively in my own VR software, so that I can run a direct head-to-head comparison with my other HMDs, and also my screen-based holographic displays systems using the same applications.” That said, he still delivers a verbose initial Oculus Rift review.
For Kreylos, praise comes right out of the gate:
…I’m very relieved that the Oculus Rift is as good as I had hoped. It’s surprisingly light, and the “ski goggle” design, which had me slightly worried, actually works. One unexpected benefit of the design is that it’s possible to put on and take off the unit without having to deal with the head straps, just by holding it up to one’s face, and still get the optimal view.
I am utterly impressed by the optical properties of the lenses, especially considering how strong they are. Once the display sits properly (and it’s easy to seat), the entire screen area is in focus and clear. This is very different from my Z800, where I’ve yet to find a position where the screens are entirely in focus, and even from the HMZ-T1 with its better optics. There is very little chromatic aberration; I only saw some color fringes when I started looking for them. Given that the Rift’s field of view is more than twice that of the Z800 and HMZ-T1, it’s an amazing feat.
But, like we’ve all heard, the resolution of the dev kit leaves much to be desired. Oculus was well aware of this long before the kit even reached Kickstarter; they say that the consumer model will have a significantly improved screen. To that end, Kreylos seemed more concerned about the ‘screen door effect‘, which comes from a display’s subpixel structure, than the low resolution:
Now, the Rift has significantly more solid angle real estate over which these pixels are spread, so it is comparatively low-res, but that didn’t really bother me. No, the Rift’s problem is that there are small black borders around each pixel, which feels like looking through a screen door attached to one’s face all the time. I found that quite distracting and annoying, and I hope it will get fixed.
He also mentions ghosting (blurring of moving on-screen content) which is noticeable especially when turning your head because the entire scene moves (and blurs) around you.
When I tried the Oculus Rift at GDC the other week, ghosting felt more prevalent in some games than others, but it’s possible that I was simply getting used to the effect. Ghosting can be fixed by using a screen with a faster pixel refresh rate (the amount of time it takes for the pixels to change colors) and is expected to be greatly improved with the consumer version.
Kreylos moves onto the software, and while he says he’ll need to get his own programs working first to check how good the calibration is, when it comes to the distortion correction, he says that “the developers did a bang-up job.”
The Rift (or rather its SDK) does lens correction via post-processing. First, the virtual world is rendered into a “virtual” camera image, which is then resampled using a simple radial undistortion formula based on a quadratic polynomial. The fundamental problem with this approach is that it has to resample a 1280×800 pixel image into another 1280×800 pixel image, which requires very good reconstruction filters to pull off. The SDK’s fragment shader simply uses bilinear filtering, which leads to a distinct blurriness in the image, and doesn’t seem to play well with mipmapping either (evidenced by “sparkliness” and visible seams in oblique textures). The SDK code shows that there are plans to increase the virtual camera’s resolution for poor-man’s full-scene antialiasing, but all related code is commented out at the moment.
He goes on to mention that the Tuscany demo gave him a “pronounced feeling of dizziness from walking,” though he couldn’t put his finger on what was causing it — he hasn’t gotten dizzy in other VR environments.
Interestingly, motion sickness seems to be highly variable from one person to the next, and it even seems to be related to the demo being used. I spent at least 30 minutes in the Tuscany demo with the Razer Hydra and had no issues with motion sickness. My first experience with the Oculus Rift and Hawken, on the other hand, gave me a bit of nausea after about 10 minutes.
Kreylos says he’ll be looking into the cause of motion sickness once he has his own software running on the Oculus Rift. I’m sure others will be researching the problem as well as dev kits continue to arrive. I’m looking forward to what conclusions Kreylos reaches after a full Oculus Rift review.
There’s more to read from Kreylos’ early Oculus Rift review, go check out his full article!
Consumer 3D Expert, Anton Belev’s Early Oculus Rift Review
Anton Belev has been running the 3dvision-blog for several years. He focuses on consumer 3D stereoscopy like 3D monitors and HDTVs. He approaches his early Oculus Rift review as someone who has experience with a number of consumer stereo systems and software and regularly plays games in 3D.
Belev starts out with some considerations for those who want to use the Oculus Rift with glasses:
Since I do wear prescription glasses as I’m a bit nearsighted, with -1.25 diopters what seemed to work best with the Rift was the middle B set of lenses as the A set produces a blurry image for me and the C set is a bit too much. I’ve also tested trying to fit my prescription glasses inside the Rift as they are pretty compact in size (the do fit inside), the effect I get with them inside using the A set is pretty much the same as when using the B set without the glasses. I prefer to use the B set of lenses as it is more comfortable than to try to wear my glasses inside the rift and if you wear larger prescription glasses you may have trouble fitting them inside.
Like many who have tried the Oculus Rift, Belev notes the low resolution.
“…looking at the Oculus Rift LCD display without the lenses it looks great in terms of detail, but since the lenses zoom it you can clearly see the pixels.” he wrote. Like many others have experience, myself included, he mentions that resolution concerns somewhat fade when you focus on the experience. “…if you stop paying too much attention to the pixels you can still enjoy what you get,” he continued.
Similar to others, motion sickness for Belev is not universal, but happens in one demo but not others.
“Strangely enough I get nausea fairly quickly only in the Oculus Tuscany Demo and not in any other of the demos I’ve tried or in TF2 (or at least not as fast as in the Tuscany Demo),” he wrote.
Belev has an interesting take on the 3D effect of the Oculus Rift. He acknowledges that, “the focus of the stereoscopic 3D support with the Rift is making things seem realistic,” but goes on to mention that the effect may seem subdued to 3D PC gamers who are used to games that provide exaggerated 3D:
And while [the stereoscopic 3D] works quite well in the demos, they may seem a bit flat for people used to playing games in stereoscopic 3D mode with a lot of depth – not intended to provide realistic proportions, but just to have a lot of depth. So if realism is your goal, it works quite well even now, though the lower resolution is a bit of a drawback here as well, but virtual reality does not need to always be true to real things, it can be used to provide “unreal” experiences as well. I suppose it can take some time for developers to pick up on stereoscopic 3D support for the Rift to be able to use it as best as possible and also to give adequate user control over the depth levels. From the currently available supported software I cannot say I’m impressed by the stereoscopic 3D support as much as by the VR experience, though both work well together.
I think he’s right about developers eventually picking up on and controlling the 3D effect. I can already think of some interesting “unreal” experiences that could be achieved by playing with depth — something like Hitchcock’s signature dolly zoom immediately comes to mind, but it’ll have to go out the window if it causes motion sickness.
There’s lots more detail to be gleaned from Belev’s early Oculus Rift review, go check it out!