One of the biggest issues with regards to locomotion in VR is that players are limited by the size of their play area. Without using teleport or slide locomotion, players are limited to movement the size of their play area. This constraint limits game designers as well as levels in the game need to be designed small enough, as players don’t have infinite play area.
An interesting idea I think we can use to solve this limitation in VR games is through the method of Redirected Motion, which mimics the sensation of an infinite play space. Essentially, this method rotates the virtual world by a small degree whenever a player takes a step. This forces the player to redirect his physical motion to avoid walls and walking out of his play area. In order for a player to travel a straight line in the game, he would have to walk the path of a curve in the real world as illustrated in the image below.
In larger play areas like playing in an open field or large room, the rotation of the virtual world would be so minimal that players would not notice it, giving the sensation that they are playing in an infinite open space. However, this method would not necessarily work in smaller rooms as players would need to run small circles in order to walk a short straight line, which can be quite disorientating.
During the advent of touch screen mobile phones, the concept of having a mobile phone that is mostly screen, save for a couple of tactitle buttons or two at the bottom of the screen, was unfamiliar to most. People of past generations were accustomed to mobile phones and digital devices having tactitle buttons to use to navigate the many functions of their devices. The buttons were fixed, always the same no matter what the application.
Then touchscreen phones came and changed everything. User interfaces were no longer designed to be centred around the devices’s limited hardware functions. The screen was now free to be whatever it wanted to be, keyboards could now vary depending on the type of application used, some user interfaces required no keyboard at all. The possibilities were endless. This is very good and all, but then comes the issue of: How do we design the user interface for an unfamiliar device, such that it would be user friendly for age groups across all generations?
The answer to this: Skeumorphism.
Now what is skeumorphism? It is a design framework, where user interfaces are designed to mimic their real world counterparts as much as possible. This way, user interfaces would be more intuitive, easy to learn and familiar to users on an otherwise unfamiliar device.
A prime example of the applications of skeumorphism, would be the first iterations of the user interface of the iPhone and its applications.
The iPhone was a completely new and alien device to users of old phones with the d-pad and everything. Yet it was so easy to use! Why? Skeumorphism. The way the interfaces are designed, look so similar to the real thing, you just know how to use them, even if you’ve never used an iPhone before.
As the popularity of touch screen phones boomed, the world became more and more familiar with the way touch screen devices worked. It has become second nature to our generation, and soon after, skeumorphism became an ugly, disgraceful thing of the past. Now, we favour flat, material design that provides less clutter to the eyes, and is overall cleaner and simpler.
Why am I talking about skeumorphism, and how in any way is this related to locomotion in VR? Why did Vivian Balakrishnan lie in parliament when he told us all that our trace together information would be private and not used for anything other than contact tracing?
Well, for the first question, skeumorphism and locomotion in VR have one very important thing in common: the importance of designing to meet user’s needs.
Learning from the past
VR to be quite frank, is not a very accessible technology, even in 2021. The average price of a VR gaming headset, is around $600. About the same price as a nintendo switch, which you THINK is popular and accessible, but really it isn’t, you’re just surrounded by rich and privilleged friends. However, we canot deny that the popularity of VR gaming has been on the rise for quite some time now.
Just like the iPhone, with VR, the possibilities are endless. With this wide scope when it comes to implementing user interfaces and features, it is hard to come up with interfaces and experiences that are comfortable and familiar to its users. Not to mention, the level of immersion that VR brings to the table is otherworldly. The illusion VR provides tricks the brain so much so that certain actions and motions in-game can cause motion sickness, even if the player is sitting on their couch doing nothing.
What are some ways that we can improve this new technology, to make it more familiar and comfortable to its users? The answer to this.. is.. you know what it is! Basically, designing VR interactions such that they mimic the real world as much as possible. This may seem pretty counterintuitive, isn’t the whole premise of VR to give users experiences that are out of this world, that are unachievable in real life? Well yeah.. that’s true and I’m not sure how to explain myself on this point. I guess in some sense, introducing people to VR is kind of like trying to teach a kid how to ride a bike. First you start with the training wheels (skeumorphism), after the kid learns how to ride the bike, you throw away the ugly, disgraceful training wheels, never to be used again.
The bottom line is: Bring the use of skeumorphism to designing locomotion experiences in VR.
Idea 1: More Audio Cues
When we do things in real life, (if you are not deaf), there are always audio cues to help you navigate and understand the world. When a player is travelling through the in game world by some means, be it walking, teleporting, whatever, it would be good to add audio cues to help players get a sense of what is going on. E.g., if a player is walking, noises of footsteps may help to reduce sensations of being disoriented, as the audio cues may help as a guide for the brain.
Idea 2: Introducing drag to head movements
When we move our heads in real life, there is a certain limitation to the speed of our head movements. Also, did you know that our brain automatically adds motion blur to our vision to avoid motion sickness? Often times in VR, the images/graphics are so crisp, coupled with the sensitivity of the HMD when detecting head movements, may cause motion sickness. We can avoid this by adding some artificial drag when players move their heads in the game. Rather than the HMD immediately responding to a person’s head movements, the game can be configured such that the change in the player’s FOV is more gradual and less sensitive to the player’s actual head movements.
Idea 3: Teleportation Improved
While I was taking CS4240, the game that my team and I developed had a function for players to teleport to locations across the map. While this is good in eliminating some motion sicknes, I actually still get motion sickness due to the sudden nature in the change of the scenery. We can circumvent this, by creating some kind of crossfade between the scenes. This can also act as a visual cue to let the brain know that the scene is about to change, like how crossfades and different transitions are used in films to switch between different scenes.
Real talk, I’m not sure if these ideas are the best, because it’s hard to say if an idea really works unless it’s backed by actual experience and research. The ideas have to be tested on real people in order to be able to conclude that the method really works in reducing motion sickness. Also, because my expertise on VR technology and interaction design is limited to only 1 module I took that spanned only 10+ weeks (CS4240), I cannot say that I am very experienced with this whole VR thing. But I have tried my best in coming up with interesting ideas. What do you think about my skeumorphic approach to improving locomotion in VR? SMASH THE LIKE BUTTON, SUBSCRIBE, AND LEAVE YOUR COMMENTS BELOW!!
VR locomotion is an integral part of the technology as the user often has to look around and shift their viewpoints in such environments. There are four main prevalent VR locomotion techniques which are motion based, teleportation, room-scale based, controller-based as well as teleportation based methods. In recent years however, many different new locomotion techniques have been introduced and are gaining traction. These techniques are mostly a variant on motion based locomotion techniques such as walking in place, one of these being omnidirectional treadmills, which helps the user to simulate VR locomotion in real life. The new Virtuix Omni One treadmill is an example of such a treadmill, which allows the user to simulate any motion and move in different directions, keeping the user in a restricted area while allowing them the perception of free movement. Unlike normal treadmills which has set speeds for the user to run on, omnidirectional treadmills involve adjusting to the user’s speed to create an immersive experience.
Another alternative to walking in place is trunk based locomotion techniques, which are based on trunk motion capture in two degrees of freedom physically leaning in or leaning back. By physically leaning, studies found that spatial representation of the virtual environment is much more accurate(https://ijvr.eu/article/view/3183 . Building on this, perhaps chairs which lean forward as the player accelerates and backwards as he decelerates or tilting left and right would also help the player reduce motion sickness. This definitely would be much easier to engineer as compared to a omnidirectional treadmill with only four directions to take into account. With a chair based locomotion technique, the player also doesn’t need to physically stand up to move around the room and physical space won’t be an issue anymore. However, a potential drawback could be on simulating a sharp turn of the head in the chair with lesser amount of directions.
In conclusion, VR is a field with many uses and applications and as such VR locomotion is still a field that has the potential for great advances which will greatly improve the viability of VR.
After some research, I came across a ‘floating head’ concept. The game will be in third-person view and players will be controlling a character in front of them. The character that they control will essentially be their frame of reference, and they can sit comfortably in their chairs while using the joystick to control the character. At certain points in the map, I think that we can also switch the player’s view to cameras at fixed points such that players can experience the game environment from another vantage point. Games that utilise this can maybe also put in pieces of a puzzle that players can only solve by turning around, observing the environment and spotting clues from that vantage point.
Navigating around a new medium like VR requires a lot of trail and error, user playtests and so on.
Motion sickness from different movements is inevitable, for the fact that there will be a disconnect from the user’s mental model and the visual image translated to what they see. To reduce the problem of motion sickness, constrains can be embedded within the game mechanics to refrain users from turning around too much or too fast. Games such as Half Life: Alyx only allows the user to move in fixed directions at the start of the game. As they become more familiarized with the environment and the controls, the game then allows the user to move freely and get used to the motions. A way to keep the user within the comfort zone is to make sense of the user’s position while playing the game.
If the user is supposed to be standing/walking for most of the game, it would not make sense to implement movements that does not translate to their position, such as sliding, rotating, etc. This strains the user’s quick-wittiness to have their eyes track the horizon and focus their point of view.
In addition, allowing the user to see switch to a 3rd person’s POV could also help greatly to reduce the amount of stress on their vision. This way, they can also see their own body movements.
I think VR locomotion can be well implemented in a game that promotes and simulates exercising. Just like how ring fit adventure gameifies exercising, by allowing players to perform physical exercises in VR, it could reduce motion sickness, since the screen would shake according to the player’s motion. Using arm swinging and running, players can travel around a world to explore, and they can perform various exercises at different places to level up and get stronger. This could incentivize players to give VR a try, and incorporate more exercises to their lives.
With numerous technologies out there to cope with VR Locomotion, we could possibly combine some of them together to come up with a better solution. For example, VR shoes which negate forward movements can be combined with a regular treadmill that handles the lateral movements so that sideways motion is supported as well. However, the drawbacks of each technology still remains, such as the lack of detection of inertia for treadmills which causes issues when a running person comes to a sudden stop.
VR locomotion is a tricky topic to tackle as considerations for how the user feels is important. It must be intuitive and at the same time, not cause sickness.
An idea that I can think of is to perhaps create a type of controller that sense the grip strength of the player. Then, combined with the eye tracking to get where the player is looking in the scene, there can be a gestured input that requires the player to exert some grip strength and a pulling motion before the player is quickly moved to their desired position based on the gaze with the peripheral blacked out.
I think that this will be intuitive and interesting as it will feel that you are exerting some sort of power with the grip strength requirement to pull yourself towards to location that is far away. With the blacking out of the player’s peripheral, the player will also be less likely to feel motion sickness.
Locomotion in VR is hard to be implemented correctly due to the fact that a wrong implementation could cause motion sickness. Most locomotion is implemented by having physical movement from the player or limited movement from the player. I feel that a good way to do this might be allowing the player to lie on a bed and he can move the in-game character by using motion tracking devices with his hand. Hence when the in-game character is moving in VR, the player would not feel too sick as he is resting his head on the bed and can be more relaxed as compared to standing upright to play the game. This might help in reducing motion sickness as the player senses are more relaxed and the locomotion in VR would not be too drastic for the player who is lying on the bed. Furthermore, the player can only move a little while lying on the bed and this might help the player to not overthink the complicated movement introduced by the VR game, allowing the player to feel secure and less likely to feel motion sickness.
One of the big problems with motion sickness in VR comes from the player’s movement being different from what the brain expects. There was this multi-directional treadmill device I saw a few years back that moved the user in the opposite direction of where they walked in the XY axis. If I recall correctly it did not allow for vertical movement as the harness is attached to a fixed point around the waist. I think an improvement would be to have the harness attached to the ceiling by 3 or 4 ropes. Then the tension of these ropes can be used to determine the player’s movement in all 3 dimensions (if the player crouches then the ropes will be pulled downwards, etc). All other parts of the setup would remain the same including the treadmill. With this setup the player can probably jump and crouch similar to in real life.
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