You may be familiar with the Uncanny Valley, the idea that photorealistic human images can cause discomfort because they're the little bit off from the real thing. At GDC Europe, Sony Immersive Technology designer Jed Ashforth put forward what he called the "uncanny VR-alley," the thinking that there's a point where virtual reality becomes so immersive that the things that are slightly off are more likely to bring players out of the experience.
It's an issue designers, like those on Sony's Project Morpheus team, are working out how to overcome as VR continues to gather steam at great pace. As you'd suspect, given the youthful state of VR development, there are a lot of problems still to be found as well as still to be solved. With that in mind, below the break you'll find Ashforth's six game design principles for VR development, including thoughts on how to avoid the uncanny VR-alley.
1. We're no longer making interactive movies
Instead, according to Ashforth, designers should think of VR development as "imagineering playable theme park rides." VR drops the window offered by the traditional screen, and if you try to present your game in the same way as you'd present it on a screen, it feels out of place - like it would in real-life.
Ashforth said his team found it's more helpful to draw people into VR by approaching it like how a theme park draws in people. It's the idea of smaller rides leading up to bigger ones, or people getting a sense or feel for the rollercoaster as they queue. To bring in new players to VR, designers need to help new players settle in, manage their expectations, and deliver thrills while making them feel secure.
2. Give the user what they expect
Ashforth said VR sits somewhere between a video game and a real-life experience, and new users tend to approach virtual reality as an analogue to real life. That can be problematic, so it's up to designers to set user expectations based on what they're trying to achieve, whether that's a closer to video game than real-life or vice versa. Elements like user interface pop-ups and scores will make the experience feel more like a video game, which may make it more palatable, but in turn you're sacrificing that feeling of realness.
If you're more striving for realness, that doesn't necessarily mean you have to go for photorealism, according to Ashforth: "I could put you in a toon-town world, and as long as the rules of that world are what you're expecting, you're completely fine."
3. The deeper the level of immersion, the more fragile it becomes
The more immersed you are in a virtual world, the more it feels real to you. The realer it feels, the more likely you'll be disturbed by something that's off, even if it's small.
Ashforth provided an example of his findings that displayed the concept neatly: Two sets of players took on a driving sim based off Driveclub assets, in which they were sat in a virtual cockpit. One set used a DualShock 4 controller, while the other used a steering wheel controller. The group using the steering wheel would see their hands marry up with their avatar's virtual hands on the wheel, mirroring their movements and increasing the immersion. However, the sim included a small gear change animation in which the avatar pressed the panel to shift gears, and when that happened it threw off the players using the steering wheel. In contrast, Ashforth said, the group using the DualShock 4 didn't have the same problem. Instead, they found the experience analogous to a video game, despite the VR viewpoint. Nonetheless, they "loved it."
4. Mismatches are inevitable
While that gear change mismatch was avoidable, some mismatches between VR and reality are much harder to deal with. It's things like body posture not lining up, or how players will always feel their contact points with the seat and/or controller, but it's also more general senses like taste and smell; Ashforth detailed how one user playing a VR space sim thought the spaceship was burning because he could smell cooked food in the same room.
"Because we're trying to give the player what they expect," he said, "they expect all these things to be right. So wherever we can match that 1 to 1, we make it more likely that players will buy into the illusion. But please remember that the fact that we can't get rid of these mismatches, it doesn't mean that you can only put content [in] that doesn't have them. Good luck finding something that doesn't have some mismatches in it, because they're everywhere. Mismatches are inevitable, that's the key of what I'm telling you."
Ashforth believes even a skydiving game, which has loads of mismatch potential, can be made into a great, immersive VR experience.
5. Never take control of the player's head!
Not literally, of course, but as Ashforth explained, when something starts autonomously taking over your view in VR it's always going to be unpleasant. As such, designers need to really think about how they're using cut scenes in VR - in a regular game, it's not so much of an issue to wrestle the camera away from the player. In VR, it really is. Sony, Ashforth said, are recommending three ways of dealing with this problem.
The first is the Half-Life model, in that scenes play out in-engine and naturally in front of the player, but the downside is that it's up to him or her to look at what's going on. The second is more unique to VR, in that it metaphorically puts players in the center of a cut scene, almost as if they're a ghost on the stage of a play. Ashforth said it's great because players still retain control of the camera, but it's easier for designers to put things in front of them and keep them focused. The third is having players look at a screen in the VR - that way you can revert to the design of a typical cut scene. The problem according to Ashforth is that despite keeping players in the VR, this technique still tends to break the immersion, in that it's "quite a weird thing" to be staring at a screen within a virtual world.
6. Player comfort must be a priority
Obviously you want players to be physically comfortable in VR, but as Ashforth explained, this goes way beyond that. VR can really accentuate things because of the immersion. If you're trying to present some kind of giant creature to the player, for example, if you make it too colossal it's going to be too much to take in. That extends to phobias, too. Vertigo, claustrophobia, fear of the dark and even a fear of empty spaces can all be brought to the surface by VR, which presents all kinds of potential problems for designers.
Ashforth presented some possible solutions for VR vertigo, say with a rickety bridge over a volcanic canyon. Designers could offer more than one route to the destination, or even let players skip the section if they don't want to do it. But there are also other more creative solutions, like readjusting the world with a player's phobia in mind. For the rickety bridge, once the game knows the player has vertigo, it could maybe make the bridge wider, or maybe turn the canyon's lava into something nicer, or simple raise the level of it.