VR and XR basics

Last modified by Maarten Struijk Wilbrink on 2022/01/24 15:07

Why VR?

In Experience on Demand, researcher Jeremy Bailenson asks you to consider a few things before getting started in building your application for VR. 

  1. Does this need to be in VR?
    Simply put, if you can do your study via either a flat-screen display, or in real life, do that. Creating for VR is hard, and there’s a lot of caveats involved. You want to make sure you actually need to use VR prior to doing so. If you know that real life is not going to cut it, Unity has excellent 3D and 2D tools available, so you could create your project for a flat screen first, to see how this works for you.
    “The easiest standard to describe is doing the impossible. If it’s simply not an option to have a behavior in the real world, then VR is a very safe bet.” (Bailenson, 2018, p.129)
  2. Don’t make people sick
    VR can cause many unpleasant side effects, ranging from a form of motion sickness to eyestrain to blinding headaches. Many of these side effects can easily be overcome, mostly by reducing the time someone is wearing the headset (anything less than 20 minutes is usually fine). 
  3. Be safe
    Since with VR your participant is wearing a miniature plant-pot on their heads, obscuring their entire vision, you want to make sure people are in a safe place. Some things to do:
    1. Have your participants sit down
    2. Make sure wires are out of the way (for example using this system)
    3. Have someone monitor your participant at all times.
    4. It is good practice to actively ensure your participants that they are both physically and socially in a safe place. Since they cannot see their surroundings, and they will most likely look pretty silly moving about in a reality people around them cannot see, they need to be ensured they will be well looked after: Safety and aesthetics aside, though, a more insidious force is at play, which sociologically speaking is probably something about “adherence to social norms” but is really the fear of doing something weird. Think about it: VR is all about you experiencing a different reality than everyone else around you.” (Rubin, 2020, p.47) 

You don’t need to strive for realism

As a continuation of the earlier point by Dr. Bailenson, you don’t necessarily need to strive for realism. We already have a perfectly real world around us, why try to recreate this in VR? VR is much more useful for situations that are much less than real. 

Most of the interesting effects of VR have little to do with how real the virtual world looks, and everything to do with how (internally) consistent the virtual world is. The effects of VR have everything to do with your field of view changing if you move your head (see below), and with having something at the location of their hands, which allows them to manipulate the VR world. For example, participants can easily learn that the virtual controller in their hands is their actual hand, or that virtual objects float towards their ‘hands’ on command, instead of having to be picked up ‘physically’ (see for example Dawn of the New Everything). 

Presence is about not breaking the experiences’ reality

Most of the effect of VR works when the virtual world is internally consistent.

This for instance means that it should be obvious which objects you can interact with, and that objects which appear to have a solid location in VR, remains solid when you walk around it. 

Some expectations of the real world do spill over in VR. For instance, when Dr. Mel Slater, at the University of Barcelona, created a bar scene for a study (reference), they found that the feeling of presence was oddly low. As it turned out, the animations and audio used for the other patrons was much too short. From the participants’ point of view, the other people in the bar were constantly doing the same thing over and over, which did not feel realistic to them. 

6DOF or bust

With three degrees of freedom (3DOF) you can rotate, but not move in space. This is for instance seen in 360 degrees video. Due to the camera being in a stationary place during recording, you can never move your head to another place than the camera was located at. While 360 degree video allows you to record a realistic scenario, the inability of your participant to move inside this space can make it feel claustrophobic. 

With six degrees of freedom (6DOF) you can both rotate and move in space. This way, your participant can fully move around the virtual space, either with just their heads (and thus adjusting their field of view realistically), or even with their entire body. This allows for a very high feeling of presence, and is what is enabling a complete feeling of being inside the virtual space. 

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