October 2, 2016

Minimum Viable VR

Those who have been working on VR for 2-3 years think of ourselves as pioneers but there’s a bunch of people that have been gathering regularly for 14 years to talk exclusively about presence. I’ve recently learned about The International Society for Presence Research (ISPR)

In April 29, 2000 before the creation of the ISPR a group of scholars settled on a definition of presence. It begins this way:

Presence is a psychological state or subjective perception…

Subjective? Not a good start. It made me feel uneasy. Michael Abrash talks about presence being the VR Magic and claims that there’s no way to create it in any other medium. Is it really presence what uniquely defines VR? Can VR claim exclusivity of something subjective?

Presence might not be the one defining property of VR but it is a new medium with a particular language that we are still developing. We will eventually be able to differentiate VR pieces in the same way we can take apart a book from a movie or a photograph from a sculpture.

The ISPR definition continues:

..part or all of the individual’s perception fails to accurately acknowledge the role of the technology in the experience

We’re making progress here. While watching TV I’m aware of the device in front of me and when using a VR headset the hardware vanishes. Well.. almost, in today’s state of the art technology you have to deal with a heavy tupperware pressing into your face and and negotiate a bunch of cables tangling into your legs but you get the idea.

ISPR follows on:

Presence is a property of an individual and varies across people and time; it is not a property of a technology or one of the technologies commonly referred to as a medium

Ok, I got it. We often lose track of time when reading a book. The brain fully engages, the reader shuts off the physical surroundings and feels part of the story. IMAX movies fill your field of view and the imagery of the crumbling glaciers in the Patagonia can be pretty close to actually being there.

While other media can trigger presence given a specific audience and content, modern VR headsets present a qualitative improvement. Michael Abrash talks about tapping the lizard brain when we drive enough parts of the perceptual system in the way is built to be driven. He shows a series of optical illusions to prove that given the proper conditions our brains can be tricked to perceive something that is not real. Those tricks work consistently across different people and cannot be shut off voluntarily. He presents the now classic example of someone walking on top of a cliff or skyscraper in a VR environment. The subject is not capable or has a hard time to step over the edge even when knowing everything is a simulation. Presence is not exclusive to VR but modern systems engage the brain at a more fundamental level than any other pre existing devices and create the illusion in a more consistent way across different people. They consolidate presence in a more tangible and objective form.

Contemporary VR systems are a leap forward in the delivery of presence but not all the headsets are created equal. Leaving performance aside, there are three fundamental kinds of systems in the market today:

  • Rotational tracking : Cardboard, GearVR, DayDream.
  • Rotational + Positional tracking: Oculus Rift
  • Rotational + Positional + Hand Tracking: HTC Vive, Oculus Rift with Touch and PlayStation VR.

Presence is both a function of the type of content and the device used to deliver it. The Netflix application on GearVR might able to trigger a sense of presence if you just seat on a couch watching a movie, perfectly still without having to interact with any of your surroundings. As soon as you want to move around or reach out into the world the illusion breaks. The set of experiences where Gear VR can deliver presence is narrower compared to devices with positional tracking, its absence creates many opportunities to break in presence. Systems like Gear VR or Daydream can only offer small glimpses of what VR is good for.

Oculus Rift (without Oculus Touch controllers) can for example trigger presence while watching a real time CG movie like the short story Henry. You can look around and the reflections and light of the environment subtlety accommodate to your head and body movements. If we want to add interactivity we have to use a gamepad. You cannot use your hands, there’s a layer of indirection between you and the environment that will likely break the illusion of being there. Without any basic body tracking is hard to add any sort of interactivity without breaking in presence.

Finally the HTC Vive is capable of delivering the experiences of all the the other systems and also provides a natural mechanism to add interactivity. It’s difficult to believe you are in a different place as a mere observer where the world is static and not reactive to your natural body movements. The Vive sets the lowest bar of a viable VR system. To build compelling interactive experiences we need a positional, rotational tracking and hands as a minimum form of body tracking. In the future we’ll see systems improving over that baseline with legs, fingers, facial tracking and improvements in haptic feedback and ergonomics but the Vive will be remembered as the first milestone of consumer VR. Thanks a lot to HTC and Valve to make this happen.