Ergonomics and User Experience applied to Virtual Reality

26 February 2020
L’ergonomie et l’expérience utilisateur appliqués à la réalité virtuelle
User experience has become a hot topic in society, whatever the sector of business. A website’s user experience has a major impact on your audience’s loyalty and your ability to attract new visitors. If a visitor easily finds the information they are looking for, if the loading speed is acceptable, if the site is well built, then they will want to stay on your site and come back regularly. However, a bad user experience will cause your readers or your customers to flee. It is the same for your mobile apps or software more generally.

In virtual reality, UX design is just as essential. We met our teams to find out more. The first thing to do is to forget about the codes of the “Web”. When looking at a computer or smartphone screen, the user has guides for size and space. In virtual reality, this is not the case. The player finds themselves in an unknown 360° space with no limits (up, down, right, and left are no longer delineated). Therefore, we must guide the user’s gaze and body in an environment that is much vaster than a simple screen. There are several aspects to consider to offer the best user experience possible and, above all, avoid motion sickness.


Motion sickness

Virtual reality has this specificity where, if your application is not well designed, there is a good chance the user will experience the effects of motion sickness. This is that uncomfortable situation which you might experience when you feel sick in your car or on a boat, for example. Virtual reality can make you feel sick as well. If you do not take your users’ physiological factors into account when designing your application, they will find themselves in this uncomfortable situation.

The problem comes from the fact that what the user sees (in their virtual reality headset) does not match what their body feels. In a sense, their brain and their senses are tricked by the simulation. For example, if you are creating a driving simulation, the user cannot feel the car accelerating or braking, and this will trick their brain and cause motion sickness. The same thing happens if the user is walking or running but, in reality, is standing still. To avoid this, there are many user experience rules that you must respect.


The basic rules of user experience

There are few rules that you should respect scrupulously to get your virtual reality application design process off to a good start.

  • The first is to think about the target experience and the play space (here, we are talking about the real environment in which the player will move). If the simulation is intended for the public, we can imagine that their space to move in will be relatively restricted in the vast majority of cases. You will then need to build a simulation with a relatively small virtual environment that requires minimal movement. For the user to not feel frustrated by a lack of entertaining decors, you should provide “teleportation” so they can discover new environments. Since the displacement is instant and motionless, this avoids causing motion sickness since the brain doesn’t expect to feel the movement in the real world.


  • The second is to inform the user about what they are about to experience so they are neither surprised nor disoriented. You need to inform them beforehand of the basic rules and what they can and cannot do. For this, it is essential to start the experience with a tutorial that summarises how the environment works (i.e. start by grabbing an object, moving around, looking around yourself, etc.). Also, it is hard to read text in virtual reality. The headset’s screen resolution has its limits. The user may have a hard time reading notes depending on the size and distance of the text. Prioritise audio instructions.


  • The user must remain in control of their actions. They cannot be an observer; they must be in the heart of the action and in control of their movements. You cannot force them to do something. For example, you cannot start a cutscene and have the camera move while the user is standing still in the real world. They could lose their balance. If you want to trigger a video, create a fixed 3D television that will show the cutscene when the user is watching that television. There are other solutions to get them to perform actions:
    • If you want to get them to look up, you will need to include horizontal lines in their field of view, represented by trees, rays of light, or skyscrapers, for example.
    • If you want the player to turn around, you will need to remember to include an object that turns and goes behind them. Moving objects instinctively attract our attention. You can also use (spatialised) 3D sound to naturally attract the user to an area.


  • You must not stop following the movement of the user’s head. Virtual reality’s strength is that the user decides what they want to look at, and they are in control of the camera. If you stop tracking, even for a few seconds, the user’s eyes will not see what they expect to see, which will trigger motion sickness. If, for one reason or another, you cannot maintain head tracking, fade to black (for example, during loading) and play a sound to inform the user that the application is still running.    


  • Velocity must remain constant: If you are making a driving simulation, you must keep velocity constant for displacement. The user cannot feel accelerations or braking. However, when the velocity is constant, the body will not feel any change in speed. If your vehicle is moving at a constant velocity, the user will have no trouble. The ideal is to create a cockpit (car interior, dashboard, etc.) so that they understand that, even if they are moving, they are inside a vehicle and their position is fixed. If you create a driving simulation that involves accelerating and braking, invest in equipment such as a steering wheel with force feedback, a seat that reproduces vibrations from the road, and an air vent so we can feel the air while we drive. Recreate as many real-world sensations as you can to match reality.



  • Use crosshairs: Aiming is not always easy in virtual reality. Use crosshairs, a sort of cursor in the centre of the user’s vision, to make it easy for them to target virtual objects and interact with them.


  • Show the interface at the right distance: If you must use text or 2D elements, place them in the simulation in a fixed way. Above all, remember to place the interface at the right distance from the user. Too close and the text will be blurry and hard to see; too far and the user will have to strain their eyes and will fatigue quickly. Between two and three metres is the ideal distance to display your interface in virtual reality.


User tests and design guidelines

Even if you respect all the rules of design, you must have your applications tested by a certain number of users to make sure your simulation does not cause motion sickness. During your tests, you may be surprised by things that you hadn’t thought of. You can check that your design guidelines are clear and intuitive (for example, highlight an object to indicate that it is interactive).

If you have any doubts, you can also do A/B testing to select the best solution for a given case. Like in traditional A/B testing, two different solutions are proposed to the simulation’s users with two goals in mind:

  • First, we want to find the solution that provides the best immersion possible. As we saw previously, the various types of feedback given to players helps to reinforce the impression of a real experience. The feedback does need to be perceived positively, however, because if not, the opposite could happen. The slightest “breach” is enough to disturb users and make the simulation very unpleasant.


  • Secondly, we need to prevent motion sickness. The slightest undesired visual effect is enough to make an individual sick. It is essential that you find the items that are causing the problem as quickly as possible. Take a floor with a geometric pattern, for example. Continuous movement on this type of floor can create a “hypnotic” or dizzying effect that we absolutely want to avoid.


Let the users test your application, and then, after a few minutes, offer them a questionnaire in which you ask them about the situations in which they felt uncomfortable and how intense they were, for example. This will help you find what needs to be corrected in your program. Physiological problems are the most important to correct, but be sure to gather testers’ overall opinion, too. You will also be interested in categorising your users by how familiar they are with virtual reality. Those used to it will have different reactions from those who are testing virtual reality for the first time.


Headsets that gather data

To conclude, know that the best is yet to come. Facebook regularly communicates on its research (even if not all of it ends up on the market), and some time ago they presented what could be the future of virtual reality. Among their announcements, Oculus’s developers are working on a system that can detect facial expressions (through sensors in the headset’s foam) that will help to reinforce immersion and translate users’ emotions into 3D. These systems will also allow data to be gathered (how you move your head, what your expressions are, what direction you are looking in, etc.). Headsets that include eye tracking are beginning to arrive on the market that can follow your pupils and analyse the places that you look at. There is no doubt that this technology will be very useful in improving virtual reality’s user experience even further. It will allow us to offer users an experience that fits their needs, with a simulation that is totally appropriate for their entertainment or consumption habits and make the user experience even smoother. With the data gathered, you will be able to position key items in the main locations that the user looks at. These are the future perspectives that await us and that will revolutionise user design and virtual reality.


Do you have a project and want some support?

Through this article, we have attempted to present the various user experience and design rules that our team has identified throughout the various projects on which they have worked. These rules must absolutely be respected when creating a virtual reality simulation to make the customer experience as smooth and pleasant as possible.

AUSY can accompany you in your innovation projects. Our centre dedicated to virtual reality can intervene at any stage of your project, from design to development to publication. Our user experience experts and testers will make sure to design the most appropriate and intuitive interfaces. Our experts can advise you in creating the most immersive experience possible.



About the author, Anthony Cardinale

Passionate about new technologies and innovation, Anthony specialises in developing immersive simulations in Virtual Reality/Augmented Reality using Unity 3D. He loves to learn and share his knowledge. He has already published many books on developing real-time 3D solutions, for example: Developing innovative apps with Unity (Editions d-booker, 13 April 2017) in which he explains how to use Virtual Reality to create six innovative applications. Anthony is head of AUSY’s 3D/RA/RV Hub in Sophia Antipolis. With the project team, he helps customers develop their innovative projects.




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