Virtual Reality Locomotion - Immersion and Gameplay

Locomotion systems in virtual reality are usually discussed in terms of comfort. Smooth locomotion can make many players motion sick, while teleportation systems typically are more comfortable. But more than that, there is also the immersive factor to consider. Teleportation and smooth locomotion operate very differently and can be used to create different feelings for the player.

Teleportation

Teleportation is a deliberate act where you choose carefully the spot to which to teleport. Typically, you won't teleport very often. In a room scale setup, you will tend to use more of the room scale space to move small distances around your teleportation point. These experiences work well when you have several stations that you will go to. So you teleport between stations, but the real action occurs in the room scale experience at that station.

By its very nature, teleportation has granted the player magical powers. Depending on the context of the experience, this can be an immersion breaking occurrence, since you can't warp around a room in the real world. But in a fantasy or sci-fi setting, you can simply explain away this ability by calling it a magical power or technology in the in-game universe.

Teleportation has a few variables that can differ between implementations:

• How far away can you teleport?
• Can you choose the direction you will face?
• Is the teleport instantaneous?
• Is there a delay between teleports?
• Can you teleport only to safe areas?
• Can you teleport to areas you otherwise couldn't reach – i.e., much higher, much lower, or through walls?

Smooth Locomotion

Smooth locomotion doesn't grant the player any special powers. It is essentially the same system that has been used for nearly every 3D game since Wolfenstein 3D. In that way it is the most familiar locomotion system. The main problem being that it tends to make people motion sick. The good news is that a lot of people do grow accustomed to it over time and stop having this problem.

In a room scale setup, smooth locomotion tends to discourage real world movement since you can just as easily move small distances as you can large distances with the controller. Though in competitive games, you may be able to use both to gain an advantage. For instance, you can dodge faster by using the controller and moving your body, unless this is accounted for in game.

There are fewer variables for smooth locomotion:

• Speed of motion dependent on analog control stick?
• Direction of movement based on hand position, control stick, or where the player is looking?
• Allow a sprint mode?
• Can you fly?

Scanner Sombre

Scanner Sombre by Introversion Software is a creepy, atmospheric walking simulator in which you can only see the environment through the use of a sonar scanner, leading to a fairly abstract view of the environment. Sound is used very effectively to set the mood and give you information about the environment. Whether you are stepping on a hard rock, a creaky wooden board, or something squishy is left nearly entirely to the sound.

Playing in VR, you are forced to use teleportation, but limited to a very small radius around you, such that each teleport is a deliberate step you take. It makes you feel like you would if you really were in a pitch black cave. You tread slowly and carefully. You can usually only take a few steps before you need to scan the area again, so it forces a slow approach. When there is a clear safe area, you can relax and walk quickly around with no problem, just the sound of your footsteps echoing through the halls.

The environment is a danger in this game and so you can teleport off ledges to your death. So if you haven't scanned well and step into the darkness, you may fall through a hole in a bridge, for instance. This element alone greatly enhances the already creepy, claustrophobic atmosphere.

The sound with the teleport is particularly interesting. Since each teleport is one step, it plays the sound of whatever you stepped on when you teleport and since you control the exact pace and interval, the immersion is incredible. You may take a few careful steps and then a few faster ones, all under your exact control. A smooth locomotion system will also play sounds effects as you walk, but each individual step is not under your control, and that one difference is huge when the audio is this important.

Robo Recall

In Robo Recall (and many other games), teleportation is more like a super power. You can teleport a considerable distance and can do so as often as you want. Robo Recall requires frequent teleporting to get out of danger as all the robots surround you. It intentionally gives you an unfair advantage over the enemies who can't teleport as an integral part of the game design.

This also encourages full use of your room scale environment as you typically will be standing and shooting for a while before you have to teleport anywhere. During this time you will have to dodge the bullets and enemies jumping at you by physically moving until you teleport away.

When you teleport you can choose which direction you will be facing so you can teleport directly behind an enemy and immediately shoot them right in the back if you want. This further adds to the tactical element of teleporting.

Rec Room

Rec Room (which I've talked about previously in What Makes a Good Online Multiplayer Game) is interesting in that it lets you choose whether to teleport or use smooth locomotion. In most games that allow this, the method of movement has little to no bearing on the gameplay, it is simply a method of traversal around the world. But in Rec Room, it actually has a major impact on the gameplay.

In a competitive multiplayer environment, having some players with smooth walking and others teleporting is tricky. How do you balance a game where the players aren't even moving in the same manner? You can't let either system have a clear advantage over the other or players that can't use one or the other will feel cheated. I'm surprised how well they were able to pull this off. Both methods have their advantages and disadvantages.

The teleportation system they use forces a two second cooldown between teleports and other players can see your teleport target on the ground. Without these limits, you could just disappear to a new location constantly and be near invincible. But during the teleport cooldown, you can still move in your room scale environment, so you aren't a stationary target either. Good teleport players learn to not telegraph their teleports very much and can zip around a map in very unpredictable patterns.

Using the smooth locomotion option lets you be in constant motion and also allows you a limited sprint ability. While it may seem that being able to move all the time is a clear advantage, in practice it is easy to keep targeting a moving player because their movement is relatively predictable. The same techniques gamers have been using in every first person shooter game still apply in VR – i.e., leading your shots and predicting where they are going.

As for immersive factors, they came up with a very clever use of audio when sprinting. You hear your heartbeat start pounding louder and louder until you are forced to walk again. Then you have to wait for your heart rate to settle down before you can sprint again. In an already tense game of Capture the Flag, having your heartbeat start pounding away when you are trying to run back to your base with the enemy flag is an amazing immersive moment.

Conclusion

So we've seen a few different approaches to locomotion in virtual reality. If comfort is the number one concern, teleportation is currently your best bet. Since a significant section of the VR market is first time VR users, they will be the most susceptible to VR sickness and it makes sense to cater to that market.

The trick is to integrate it into the game as tightly as possible. Scanner Sombre highlights the player's vulnerability by limiting the teleport and using fantastic sound design to heighten the sense of danger in the world. Robo Recall, instead, highlights the player's strength by making the teleport an excellent battle tactic, and not just a way to move through the world. If you switched these two systems between these games, the results would be game breaking on both ends.

As the VR market grows, there will be an increasingly large amount of players that have no VR sickness problems. It seems quite common that once people build up their "VR sea-legs," they can do pretty much anything. The reality is that many games and experiences require more than what teleportation can do.

If you are able to offer both, you should. In a puzzle or exploration game, where the movement is not integral to the gameplay, you will have no problems offering multiple locomotion methods. If you have a multiplayer game, you will have to balance the game accordingly. In the worst case scenario, you will have to divide the players so only the same type of locomotion can play together.

As a total aside, I spent some long sessions in VR while researching this post and working on other VR projects, so I picked up a set of VR Covers for my headset . I strongly recommend anyone using VR get these. They are so much more comfortable, leaving much less of a mark on my face. Not to mention that they are washable, so you don't have to worry about sweating with these on. This isn't sponsored or anything, I am just very happy with their product.