UX Design for VR : The Basics — Part 2

Key considerations to get started with designing in VR

This is the second of a series of articles covering different key considerations for getting started in designing for VR. The first part can be found here:


Designing Movement

One of the primary design considerations for VR must be to ensure the user experiences minimal to no motion sickness throughout your experience. The primary cause for motion sickness is cognitive dissonance between what your brain thinks to be true and what your eyes see. For a truly immersive experience, the user must believe what they see is real. For example, if a user feels like they’re flying in the air but can actually feel their feet on firm ground, there is inconsistency in their perception which can cause motion sickness. These contradictions affect different people in different ways and have been noticed to make a number of users sick. An interesting way in which the VR experience ‘The Cubicle’ addressed this problem was by moving the floor with you in VR. This actually makes the user feel like they’re floating because even in VR, their feet are on the ground and there is no contradiction between what they see and know.

Similarly, for experiences where the user is seated and movement is with the press of a button, users may feel disoriented because their brain knows they’re seated yet they’re moving in VR. And remember, rapid movements are always bad in VR.

There are a number of factors, depending on the kind of experience you’re designing, which must be tackled to minimize motion sickness.

Seated experience without movement in VR

For a seated experience without movement, motion sickness is unlikely. If the users still feel sick, it may be most likely in case of lag or frame dropping on moving the head. In that case, the scene should be optimized (for example, polygon reduction) to ensure better quality. Another good design consideration would be to have everything interactive within the field of vision to avoid repetitive head movement, which is an ergonomic consideration as well.

Seated/Stationary experience with movement in VR

a. Button/Touchpad Press: For a seated/stationary experience with movement, it is often implemented with a button press or swipe and press (GearVR) which causes the player to move in the virtual environment. For devices such as the GearVR, this is the most common approach for movement. However, it has to be done carefully so as to not cause motion sickness as the user would know that they’re seated while they’re moving in VR. A measure to remember in such a case is to optimize the speed of movement. A rapid speed will make the user sick and low speed will bore the user. The speed should be iteratively tested over multiple users and values to find the optimized solution.

Movement with button press

Another personal observation in this case is that users perceive speeds differently depending on the kind of space they are moving through. Movement through a more populated room may feel different than movement through an empty room at the same speed. So while user-testing speeds during prototyping, it is recommended to populate the room as close as possible to the expected final setup of the room.

b. Teleportation: A popular way to enable movement without causing motion sickness is teleportation. This works by allowing the player to point at a certain position using their controller and pressing trigger, and they get teleported to that place automatically (example, The Lab, Budget Cuts). There is no movement so motion sickness is not a problem. However, some users find the sudden change in position and/or perspective, disorienting. So the recommendation for this is to avoid successive teleportation over a short period of time.

Teleportation in ‘Budget Cuts’

VR Experience with corresponding physical movement

This usually causes least amount of motion sickness because there is no contradiction with your real-time and virtual movements. This is the best way to avoid motion sickness but poses a major limitation on movement in your experience to the space in which your VR device is setup. (example, NVIDIA VR Funhouse, the Blu)


Immersion

It is implied that you want to design an immersive VR experience. This naturally depends majorly on the content and theme of your experience but some general principles to keep in mind may include:

Environment

The environment should be made to look as realistic (or relevant) as possible. The relative scale of the objects in the environment as well as the clarity of these objects (such that closer objects are clearer than objects far away) are factors which constitute a realistic environment.

Physics

The world should behave in VR as it would in real life (for example, In terms of gravity and collisions). Realistic physics is particularly delightful for users because it just makes the overall experience more believable and adds immersion tremendously.

Affordances

As mentioned earlier under interaction, affordances should be kept as relevantly close to the environment as possible to maintain immersion. The lesser the instructions to the user, the better it is. Users generally don’t like being told what to do. As with any other design, intuitive controls and interactions are key to a good experience.

Audio and Visual

Stunning aesthetics and immersive audio definitely help in keeping the users engaged. These should however, not be overwhelming.


Ergonomics

The importance of ergonomic design for VR can be emphasized in one simple sentence — If you want your users to stay in the experience for long, you have to make them comfortable. With VR, users are trusting you with their bodies and minds. It is highly important that you respect that.

Though ergonomic design practices for VR are still being explored and developed, some common guidelines to follow for now may include:

Interactive Space

As mentioned earlier, having the most common interactive elements within the field of view (especially with gaze) and/or within easy reach/access (especially with controllers) is highly important to avoid repetitive head movement and neck strain. Iteratively user-test for optimizing the height and field of vision while placing interactive elements in your scene.

Visual Comfort

Ensuring the use of acceptable colours and brightness so as to not hurt your users’ eyes is also of utmost importance. Many users have headaches following VR experiences with high brightness, flashes or strong colours.

Soundscapes

I read this first in Jonathan Ravasz’s article — Design Practices in Virtual Reality and started noticing it in a few VR experiences. This is definitely, a good way for transitioning the user from one environment to the other, by fading-in an ambient soundscape first and then bringing in the visuals. This helps the user transition gently and get prepared for the environment they are switching to, by allowing them to visualize the surroundings based on the sound so as to not overwhelm the user.


VR Hardware

Last but not the least, how do you choose which VR headset you’re designing for? Choosing a device can depend on multiple factors, including but not limited to, portability, expense, tracking, criticality of high FPS and target audience.

Not to say that you cannot design for multiple headsets (as that was the first experience I designed), but that generally implies a trade-off on quality or fidelity to ensure good support on different kinds of devices. For example, the GearVR supports up to 60fps whereas the HTC Vive supports up to 90fps (depending of course on optimizations), which means HTC Vive can support heavier assets and high polygons better than GearVR.

On the other hand, GearVR is a much cheaper headset to afford and build for, not requiring a high-performance PC to run as is required for HTC Vive. GearVR is also more portable but lacks physical tracking like HTC Vive.

So choosing a headset depends majorly on what kind of experience you’re designing and what priorities you have, but these are a few parameters to base your choice of VR device on as they all have their own advantages and disadvantages. Plenty of information about the comparison of the specs of these headsets can be found online.


Conclusion

There is a lot more being explored and developed in the VR space as we speak, but this may be a good place to start experimenting with this technology. Keeping some of these considerations in mind is likely to set you up for a good starting point and prevent you from reinventing the wheel. As someone rightly said, “Learn from past mistakes — preferably someone else’s.


References

  1. Jerald, Jason. The VR Book. 1st ed. Print.
  2. “How To Design For Virtual Reality”. Backchannel. N.p., 2017. Web. 6 Jan. 2017.
  3. “Design Practices In Virtual Reality”. uxdesign.cc — User Experience Design. N.p., 2017. Web. 6 Jan. 2017.