That is a fundamental real-world constraint that must be considered when creating large scale virtual realities. So often a VR developer comes to us saying: "I have an amazing idea, but I need more space." Many clients with a 10ft x 10ft area discover that this is simply not enough to accommodate all the play, work, and training that the VR environment demands. The challenge of solving the space issue is common to most VR experiences. You will never have an infinite amount of physical space to correspond with the virtual space you are trying to produce, and we so rarely want to create small virtual spaces.
So, when most games and training scenarios require users to have some form of mobility, how can we accommodate this? Many developers have accepted difficult compromises when dealing with the VR estate problem. We offer creative solutions to effectively amplify the space and/or design around these space limitations. The most common solution is a VR treadmill, but it is not the only solution to the problem. As much as we're happy to provide one, solving the virtual real estate problem is the core of our business model, and this article will analyze the alternative methods. Read on if you are interested in the various techniques we apply to maximize the amount of space available in your virtual world.
Sometimes designing an application so that the user doesn't have to move around is the best approach. There are plenty of successful examples out there (yes, I'm looking at you Beat Saber). If you design your application so that each level/scenario happens at a fixed location or so that points of interest come to the user, instead of the other way around. Your content will be much more intuitive, as the user doesn't need to learn how to move around and learn how to use the application. This is a huge perk. This method is well suited for a wider audience that may never have been in contact with VR before.
Manual locomotion is common in a lot of in-home content. Manual locomotion encompasses all means of locomotion that are activated by the user's hands. There are myriad mechanisms spanning from joysticks, to various forms of point and shoot teleportation, to pointing your remotes in the desired direction of movement and shaking them to move. All of these methods share a significant down-side; they come with a learning curve. This is acceptable for in-home entertainment but does not suit location-based entertainment and training because the learning curve detracts so much from the primary purpose.
Additionally, each manual method usually comes with its own set of challenges. This is why there are so many being explored. Joystick-motion may create nausea while teleportation breaks game mechanics -and many users find the concept hard to grasp initially. In fact, when tools to trigger and direct motion are the best option, good practice means implementing more than one and letting users choose according to their preferences. Look at almost any game available on Steam or VivePort and you'll see one or more of the above solutions used.
The primary downside to manual locomotion is teaching the user how to move around while they can't see you. The setup does not support the operator in assisting the user; The operator can't simultaneously see the user and what the user is seeing. Typically direction is attempted whilst all the while sound effects are blaring into the user's ears.
In order to save ourselves from all that, assisted locomotion switches the dynamic and allows the operator to move the user around the environment. This has the huge advantage of removing the user's learning curve and giving the operator control over the user's perspective on the environment. Various implementations are possible. The number keys can be used to move the player to various points of interest. The operator can click on a mini-map to initiate player teleportation. Or the operator can partake in the VR experience with an avatar and choose between teleporting themselves or teleporting the user. These are great ways of implementing locomotion for engineering design reviews or showcasing real estate but, needless to say, they do not work for games and, if used carelessly by the operator, will result in the user being disoriented more than anything else.
Free Roam VR is a brute force approach to generating large scale virtual worlds: use more physical space. And, where space is readily available, its a viable solution! It is, by far, the most direct and intuitive way of navigating large scale virtual spaces. However, there are some elements designers need to consider when using these solutions. Firstly, the larger the required physical space, the more likely it is that each VR deployment will need to be customized to fit that space.
In the real world, ceilings hold up thanks to walls and columns which need to be taken into account when designing the VR content. Small scale (30ft x 30ft) free roam has been popularized in the entertainment sector, but anything larger than that will usually require one or more specialists to adapt the content to the space parameters specific to each deployment. Where permanent installations are prominent, or only a small number of simulations will be required, and where space is plentiful, free roam is definitely the way to go.
We usually choose our locomotion method as a function of our content. But what happens when we design content based on locomotion? Embracing the method's limitations allows designers to create a perfectly immersive experience. This is why you get amazing content such as Budget Cuts and Vox Machinae- which use means of locomotion as an integral part of their game-play rather than being an independent means of moving around.
Budget Cuts uses the teleportation system as a means of spying on enemies before actually teleporting to a new location. Unlike other games that become partially broken due to teleportation, Budget Cuts makes it part of the experience and a tool to be mastered for success. Vox Machinae embraces the fact that the user fixed in place in the cockpit of a huge mech, with the locomotion controls simply being a part of every other mech control within reach of the user. Mastery of these controls is part of mastering the game. Although this approach can't be used for every use case and each implementation is custom to a given application, the outcome from applying such a creative approach makes for a truly immersive and seamless experience.
Virtual reality treadmills are unique on this list as they allow the user to roam unlimited virtual space. Their principle of operation is fundamentally simple; when the user moves in one direction, the floor of the treadmill moves in the opposite direction. Given this freedom to use as much virtual space as desired removes many constraints when designing for a virtual application. The right treadmill technology creates a meaningful user experience, as there is no need to learn how to move around the virtual environment. High-end treadmills do not feel significantly different from walking around normally. So, with a VR treadmill, you get all of the benefits of manual locomotion but without the learning curve and potential side effects.
When it comes to choosing a method, it's important to consider the following three criteria:
1 User Immersion:
The means of locomotion you choose will affect the user's sense of immersion in a number of different ways. Just giving the user the ability to explore large virtual worlds will greatly enhance the degree of immersion experienced. However, having to learn a new way of navigating this environment or dealing with physiological side-effects and broken game mechanics will negatively impact the overall believability and usability of the application.
2 Design Flexibility:
Locomotion provides flexibility to the developer in the way that the virtual world is constructed. Some things simply aren't possible in a 10ft by 10ft space. However, each method comes with its own set of constraints which may affect the game's mechanics and the physical layout of the virtual world, thus transforming constraints rather than eliminating them altogether.
3 Cost Efficiency:
Some of the methods described here come free or for a small licensing fee, as they only involve software. Some methods require space and a large number of operators, which in turn, incurs ongoing costs. And others require specialized hardware, which usually involves a higher upfront investment.
It is not possible to compare such disparate locomotion methods objectively with one another. Each method has its strong points, but the importance of these strengths varies greatly from one application to another. Let's briefly analyze each of the locomotion options, using the above criteria which will provide a sense of the suitability of each option for common use-cases.
No Locomotion: Low Cost - Immersion
The level of immersion is good, but the user will not get the sense that he/she is partaking in a virtual world of massive scale.
The developer has to work with the significant constraint of bringing points of interest to the user.
Manual Locomotion: Low Cost
The level of immersion is negatively impacted by the imposed learning curve.
The developer needs to consider the means of locomotion and how it will affect other interactions.
It's almost free. There may be small development costs and/or licenses to pay for.
Assisted Locomotion: Low Cost - User Immersion
The level of immersion is very good
This only works for some very specific use cases
It's almost free. There may be small development costs and/or licenses to pay for.
Free-Roam VR: User Immersion
The level of immersion is great. However, the sense of scale is a function of the physical space available.
It opens doors in regards to the design of the experience, although many constraints remain due to finite space.
There are significant costs to consider with the tracking systems, backpack PCs, headsets, batteries etc., as well as the real-estate and staff required to operate the systems.
Raw creativity: User Immersion - Cost Efficiency
When your locomotion is a meaningful part of how the virtual universe works, it adds significantly to the sense of immersion.
It works for a one concept virtual universe only and doesn't work well in the simulation industry.
It's almost free, although custom development is almost always necessary.
Treadmills: User Immersion - Design Flexibility
Walking on a high-end treadmill is the same as walking in your everyday life. Additionally, the sense of scale and exploration that comes with infinite worlds is unparalleled.
The flexibility provided by infinite space is amazing for game or simulation design.
The significant cost is the acquisition and maintenance of the treadmill.
Hopefully, you are now in a position to solve your own locomotion challenge. There is no one size fits all, and, as with most design decisions, it all boils down to your unique use-case. The users you are targeting, the development team you have access to, and the revenues/non-revenues that your project will be generating will all determine which solution is right for you. If you would like to access professional advice specific to your project, you are welcome to reach out to Aperium or to the community!