[Roomscale Tower Crack Fixl
Julieann Rohde
I've been doing virtual reality game development for a year now. In terms of relative industry time, I'm old and experienced. I wouldn't call myself an expert though -- there are many far more knowledgeable people than I and I defer to their expertise.
This article covers many of the unique design challenges a VR developer will face within a roomscale play environment, how many VR developers are currently handling these design problems, and how I've handled them. There are a lot of general VR design choices which can impose some big unforeseen technical challenges and restrictions. I share my lessons learned and experiences so that anyone else considering working in VR can benefit from them. In the interests of being broadly applicable and useful, this article focuses more heavily on the design challenges and concepts of an implementation than the math and code implementation details.
In the interest of getting deeper into the technical details quickly, I'm going to assume that everyone here knows what virtual reality is and generally how it works. If you don't, there are plenty of articles available online to give you a basic understanding.
Motion sickness is a real thing in VR. I've experienced it many times, and I can make other people experience it as well. It is nauseating and BAD. Do everything you can to avoid it. I have nothing but contempt for developers who intentionally try to cause people to get motion sick, even if its a part of their 'game design'. I have a working theory on what exactly causes the motion sickness, but I'll start by talking about a few popular VR experiences and what caused the motion sickness.
The initial jump jet thrust into the air was no problem for me. Changing my flight direction in midair was a huge problem though. When you're in flight, you don't have anything to use as a visual reference for your delta velocity. You see the ground below you moving slightly and your brain tries really hard to precisely nail down where it's spatially located, but there isn't any nearby visual reference to use for relative changes. If the designer insists on using jump jets, what they should do is place small detail objects in the air (dust motes, rain drops, particles, etc). Avoid letting players change velocity in midair.
The second part which caused me discomfort was the actual landing, when the mech hits the ground. I don't remember exactly, but I think the mech had a bit of bounce-back when it landed, where the legs would insulate most of the force of the landing. Visually, you'd get a bit of a bob. Remember that braking is also a form of accelleration, and accelleration is a big culprit of motion sickness.
One other notable VR experience was this game called "The sightline chair". It was supposed to be a comfortable experience, but the ending was stomach churning. The gist of the game is that you sit in a chair and look around. The world changes when you're not looking at it, so you gradually move from a forest to a city, to who knows what. At the very end of the experience, you are sitting in a chair at the top of a sky scraper scaffolding, on a flimsy board. I don't necessarily have a fear of heights, but looking down was scary because I knew what was about to happen next: I would fall. The scaffolding collapses, and not only does the chair you're in fall down, it SPINS BACKWARDS. Do NOT do this. NO SPINNING THE PLAYER! I didn't even let the falling sequence finish, I just closed my eyes and immediately ended the "game".
Someone had published a rollercoaster VR experience which they built rather quickly in Unreal Engine 4. I knew it would make me motion sick, but I was studying the particular causes of motion sickness and had to try it out for science (VR devs suffer for their players!). The rollercoaster experience took place in a giant bedroom and followed a track with curves, dips, rises, and other motions. Essentially, they are taking your camera and moving it on rails at different speeds. So, I was expecting accellerations and thus sickness. The first time I went through the rollercoaster, I felt somewhat bad afterwards. I then did it again, and felt much worse. The lesson here is that motion sickness is a compounding, accruing effect which can last long after the VR experience is over. If you have even a little bit of stuff which causes people to get motion sick, it will build up over time and people will gradually start feeling worse and worse.
I think it's also worth noting that a VR developer will need a very high end computer. I went to a hackathon last summer and had a pretty nauseating experience. First, I drank one beer and was slightly buzzed. First mistake. Then, I went to see some enthusiast guys demo on an Oculus DK1, which is an old relic by todays standards. Second mistake. I decided to stand up. Third mistake. He ran the demo on a crappy laptop. Fourth mistake. Then he ran some crappy demo with lots of funky movements and bad frame rates. Fifth mistake. I could only get about half way through before I started feeling like I was about to fall over on my face, so I had to stop. Don't do any of this! It's not worth it.
Anyways, let's talk about the game I'm developing and what I discovered to be trouble spots. The game begins at the top of a wizard tower. You can go between levels in the tower by walking down flights of stairs. I have two types of stair ways.
The curved stairs generally cause SPINNING and spinning generally causes motion sickness. The stairs which take players between levels of the tower are okay, but there's a chance that players can jump down instead of taking one stair at a time (which potentially causes motion sickness). So, to protect the player from themselves, I put banister railings and furniture to block the player from jumping down directly. They could still try if they were determined, but I did my part to promote wizard safety and broken knees. I find it helps to imagine that an occupational health and safety inspector is going to come look at the environment I built and tell me where I need to put safeguards to protect the player from unintentional hazards. Of course, that's not going to actually happen, but it gets you thinking about your world as if people actually had to live in it and how they'd design it for their own health and safety.
The other surprising cause of motion sickness is the terrain and movement speed of the player. Your terrain should generally be SMOOTH. From a level designers standpoint, it's tempting to add a bit of roughness to the terrain to make it look less artificial, but every bump in the terrain causes the player VR headset to go up and down, and this is a small form of accelleration, which, causes accruing motion sickness over time. Smooth out your terrain with a smoothing brush. If you want hills or valleys, make the slopes gradual and smooth. The faster a player travels over any object which causes the camera to go up and down (stairs, rocks, logs, etc) the more likely they are experience motion sickness and get sick. To hide the smoothness of your terrain, use foliage and other props to cover it up.
Keep in mind that when you are building a VR game and designing things within it, you will be building up a tolerance for motion sickness susceptibility. You become a bad test subject for motion sickness. Try to find willing guinea pigs who have very little experience with VR. When you find these willing guinea pigs, be very sure to do a pre-screening of their current state! And, very importantly, keep a barf bag nearby! We had two incidents during testing:
Was it our game which caused sickness, or were these people feeling sick prior to playing? It was impossible to isolate the true cause because we weren't conducting a highly controlled test. This is why you pre-screen people so that you can control your studies a bit better.
At the end of the day, VR developers owe it to their loyal players to make their VR experience the best, most comfortable experience possible. Uncomfortable experiences, no matter how great the game is, will cause people to stop playing the game. Nobody will see your final boss monster or know how your epic story ends if they stop playing after 5 minutes due to motion sickness.
Virtual Reality is not a new form of cinema and it's not gaming. VR is also not a set of fancy, expensive goggles people wear, though it is a necessary component to creating virtual reality. Virtual Reality, and the goal of a VR developer, is to transfer the wearer and their sense of being (presence) into a new artificial world and do our best to convince them that it is real. Our job is to convince players that what they're seeing, hearing, feeling, touching, and sensing is real. Of course, we all know it isn't 'real', but it can seem to be very convincing, almost to a frightening level of immersion. So, a player loans to us many of their senses and their suspension of disbelief, and in exchange, we give them a really fun, immersive experience. The second most important goal of a VR developer is to create and maintain that sense of immersion, that feeling of actually being somewhere totally different, of being someone else entirely different.
Generally speaking, the virtual reality players game experience should match their expectations of how they think the environment should look and react. If you create a scene with a tree in it, players are going to walk up to that tree and look all around it and expect it to look like a tree from every angle. That tree should be appropriately scaled to the player avatar, and should not glitch in any way. Remember that you don't control the camera position and orientation, the player does. So, consider the possibility that the player will look at your objects from any angle and distance. If the object mesh is poorly done, immersion is broken. If the object texture is wrong, immersion is broken. If the object UV coordinates and skinning is wrong and you've got seams, immersion is broken. If players can walk through what they expect to be a solid object, immersion is broken.
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