Written by: Callum Hurley @MultiCallum
In 2016, Oculus co-founder Michael Abrash stood on-stage at Oculus Connect to talk about the future of VR. During his talk, he looked at where VR was at the time (this was around six months after the launch of the Oculus Rift CV1), and where he believed VR would be in five years, from a technical-specification perspective.
At the time, Oculus Rift featured a 1200 x 1080 per-eye resolution and an FOV of just ~90°, with a fixed depth of focus distance of 2m and a pixel density of 13.3 pixels-per-degree. The predictions for where VR would be five years later in 2021, was a per-eye resolution of 4K x 4K with an FOV of ~140°; equating to ~30 pixel density, and a variable depth of focus distance. Looking at those predictions, some of these may stand out to you, so let’s take a quick dive into all four topics. Display Resolution
Of the four tech-specs focused on here, display resolution is easily the most improved since 2016. If you use a Quest 2 or a Valve Index, then pop-on a Rift CV1 or HTC Vive, you’ll immediately notice the individual pixels, the blurry imagery and of course, the god-rays (particularly with CV1).
Quest 2 features a 1832 x 1920 pixels per-eye resolution, while Valve Index features a 1440 x 1600 per-eye res. There are some devices on the market that advertise “4K displays” such as the Pico Neo 3 with its 3664 x 1920 per-eye resolution, though these are not technically “4K x 4K” per eye, as Abrash’s infographic implied. However, let’s not forget the HP Reverb’s 2160 x 2160 display (4K x 4K) or the Pimax 8K, with a per-eye resolution of 3840 x 2160.
So, resolution-wise, we are sort-of on track with Abrash’s predictions! We do in fact have 4K displays in some of our HMD’s, even if they’re not necessarily 4K x 4K, and they’re not in the most popular or mainstream headsets. Field of View
In 2016, the Oculus Rift CV1 featured an approximate 90° field of view (which bizarrely, was smaller than the 100° FOV of the Oculus DK2 that came before. Abrash’s prediction was that by 2021, we would have around 140° field of view in our VR headsets. Firstly, it’s worth noting that FOV can vary in many headsets due to IPD adjustment, so I will be using the largest FOV possible on each headset.
Now, this is a trickier one to look at. While on a technical level, this has been achieved and surpassed thanks to Pimax 8K’s 200° field of view and StarVR’s 210°; we have to wonder, was Abrash speaking of this progression in terms of capability or active use? Pimax and StarVR have large FOV’s but with known warping issues, to the point where no mainstream headsets from Oculus (Meta), HTC or Valve have utilised them. As far as I’m concerned, FOV has not had nearly the attention it needs, and has been stagnant for far too long. The two most popular VR headsets in 2021, the Quest 2 and Valve Index, feature a 104° and 130° FOV respectively.
So yes, this is on-track from a technological perspective, but we’re not seeing this in our biggest VR products today.
Pixel Density is determined based on the display resolution divided by the field of view, so this varies from headset to headset. 2016’s Rift CV1 featured at 13.3 pixel-per-degree density. (These will all be based on horizontal pixel density). The Quest 2 features an 18.4 pixel-per-degree density, and the Valve Index sports a 13.3 pixel-per-degree density.
It’s worth noting that pixel density is hard to properly calculate and track in VR due to distortion and software-based distortion correction to suit VR, not utilising 100% of the pixels on the display panel and the display resolution being counted per eye and divided by the FOV of the entire headset, not to mention the display overlap which is quite important in headsets like Valve Index and Pimax 8K. I am simply going by the same logic and calculation that Abrash used, for comparison.
Nonetheless, based on Abrash’s own method of calculations, we have not achieved the pixel density he was hoping for.
Depth of Focus
Oculus Rift CV1 had a focal distance of 2 metres. The hope here was that by 2021, this would be variable. Unfortunately, that is simply not the case. Prototypes like Oculus Half Dome 2 have been very promising, and just this year they claimed that varifocal lenses are nearly ready for use in a commercial product, which is exciting.
But as of right now, past 2021, Quest 2 has a focal distance of 1.3m, while other headsets like Valve Index use a focal distance of 2 metres. The prediction of variable focal depth in VR by 2021 was unfortunately not to be.
Results and Thoughts
So, 5 years after Michael Abrash’s 5-Year Journey for VR was laid out, we can see that of his 4 predictions, only 2 came to pass. Resolution and Field of View have improved to the extent he believed, though those FOV improvements aren’t making it to many homes yet. However, Pixel Density (by his own calculations) and Depth of Focus have not reached the heights predicted. It’s worth noting that Abrash himself has retracted many of these predictions as the years have passed, accepting that he was at time over-ambitious and in some cases (likely resolution) may have been too underestimated.
Why this is the case, is up for debate. Resolution has been improving across industries, so it only makes sense that VR would keep up, these displays have to be sourced from somewhere! And with newer technologies such as MiniLED and MicroLED coming to VR soon, this should only evolve faster. FOV improvement will require a complete redesign of the optics used in VR, and it seems as though current HMD manufacturers have decided that approximately 100° is ‘good enough’ for now.
My personal belief is that as of around late 2017/early 2018, both Oculus (Meta) and HTC (and now Valve) decided to focus less on R&D, and focus more on turning these headsets into a marketable product for commercial sale. This is unsurprising given that at that time, PlayStation VR was far outselling Oculus Rift and HTC Vive despite it’s technological drawbacks. However, with the enormous success of Quest 2 and Valve Index, could we start to see a strong push in VR R&D again? I certainly hope so. What do you think? Let me know on Twitter, I’d love to learn more from all of you and hear your thoughts & opinions.