PyWeek - Nausea warning.

It's becoming apparent that some people's experience of our game is inducing motion sickness, if you suffer from motion sickness please run the game in windowed mode (change it in options and then restart the game). If you still feel nauseous then you probably should stay clear of it, sorry :-(.

Chard on 2008/09/15 16:25 of Super Effective 7


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The game looks great, and it was fun playing until I felt sick. I just can't imagine why you thought it was a good idea rotating everything but the player. Couldn't you create a more 'classic' version with normal scroll where the player moves around? It would look fantastic!
Echo! Echo! (I am echoing Woodwolf's comment exactly)
Hmm... I had no problem at all. ^^

Woodwolf, pymike: I'm surprised! Lots of games rotate the view around the player, including about 90% of 3d games. Do you have problems with those as well? I want to understand what's causing the motion sickness, so that we can minimise it in future. I don't believe that it's simply a rotating camera, simply because of the huge number of games out there with this feature. I'd like to do some more experimentation, but as I said on IRC, nobody at Super Effective suffers from this problem (or we'd have noticed it a lot earlier).

As for the 'classic' version idea, I do feel that the rotating viewpoint is a core gameplay mechanic, and removing it would change the game completely. It saddens me that people won't be able to play our game because of it, but if we removed it, I don't think it would be the same game any more. Does that make any sense?

ServalKatze: Glad to hear the problem isn't universal! I was a little worried for a while there.

I don't have too much of a problem with this game, I get strong motion sickness from FELT motion that's not SEEN (thus, carsickness, airplane sickness, elevator sickness etc) but not the other way around; fortunately. But I know people who do get motion sick, and this game obviously presses all the buttons. Here are some factors that I think play into that.
  • Bright colors - the color scheme is a bit trippy to start with, not that that's a bad thing, but it can give a real impression of the screen not being flat. Objects sort of stand out, and nothing looks quite real. It could make someone a bit queasy before it even starts turning, if they are color sensitive in that sort of way. I don't think this is a huge factor, but it probably enhances the experience.
  • In real life, we don't actually sense speed. What we sense are forces, or acceleration. The rotation in this game has a very wobbly acceleration from slower spinning to faster spin. When you stop touching the controls, it keeps turning. This acceleration up to speed, and then deceleration when you stop, can enhance the feeling that the room is spinning around you.
  • Desyncronized spin - the onscreen avatar, which most players will see as themselves, is not in sync with the spin of the camera. When you turn left, he turns left a little faster than the camera, and then the camera sort of catches up. By itself, this might be OK, but combined with the deceleration factor, it can really keep the mind guessing. See, when things are moving, we tend to try and predict where they are moving to. With all of these things out of sync, the mind can get really confused about where it thinks things should be, and where they are. And it only gets worse when you move up or down, and your character moves on the screen.
My dad does get motion sick by the way from some games, while others are fine. The ones he has the most trouble with, tend to be first person shooters which have the bobbly walk thing happening to the camera. He can't take the camera not moving exactly where he points it. Generally, most 3d games don't cause a wide amount of people to have motion sickness, because the camera either stays fixed 80% of the time (with slight adjustments every so often) or at least is predictable in it's movement. Tweaking the values may or may not fix this game, although I doubt it will help very much. Fixing the camera to the character, and using velocity instead of acceleration for turning would go further.
On top of everything that Saluk wrote, the more fixed reference points, the better. This is why head bob and gun bob can be such key factors for inducing motion sickness. The head bob moves the horizon, and the gun bob moves the foreground -- keeping one or the other still can help keep people feeling rooted on the ground. In this game, you have neither a stable background (it rotates), nor a stable foreground (the camera's loose mounting to the character).

I get very motion sick in the car if I try to read a book or a map, but if I put this game in a small windowed mode, I'm able to have enough peripheral stability to let me play for several levels before I have to stop. It's a testament to how fun the game is that so many of us keep playing, despite it making us feel uncomfortability. :)

Color blindness and motion sickness are two issues that affect large numbers of people, but aren't often considered when developing games. Similar to the Retro Remakes contests, I sometimes think it would be cool to do a restriction based around making more accessible games, since things like this are so easy to overlook.
I like the nausea! The disorientation is part of what makes this game fun for me. I hope this isn't insensitive of other people's hardships, but I don't see what's the big deal: it's hard for me to imagine lacking the physical fortitude to play a video game. So I don't think you should change it. If people don't want to play it, well, not every game is for everyone.
I haven't had the time to play any of the games yet, but this discussion reminds me of something I've read about Mirror's Edge. This isn't the case, I think, it's just a curiosity. In that game, to prevent motion sickness, they added a fixed white dot in the middle of the screen, so the player has something fixed to focus his eyes on (topic #4 on this interview, though this isn't where I first read about it).
(Also, googling simulation sickness might be interesting.)
saluk is right. The fact that absolutely everything (besides the text) is rotating, makes me feel sick. I've played FPS on big and small screens, and I've played fast-paced racers, and they don't make me feel sick. Probably what's the problem is (like saluk pointed out) the vivid colors on all the objects. I'd probably play this game to death if the camera didn't rotate, but as it is, well, I can't play more than a minute or two.

Cosmologicon: There's a big difference between disorientation and nausea. Although I've never had a problem with video games, I do occasionally suffer from real-life motion sickness, and it's really quite an unpleasant thing. While we were certainly aiming to disorient the player a little, we definitely weren't trying for nausea.

Thanks everybody for all your comments. I'm coming to the conclusion that there probably isn't much that can be done for Digby Marshmallow to prevent people from feeling ill - it's just down to a couple of basic facts about the game design. We'll certainly cut back on the desynchronized spin in future releases, and maybe try to add some more static points of reference. However, I think there are always going to be some people who can't play the game.

I just don't know the reason, but I've played FPS games all my life and I've had no problems at all. I even finished Descent! In those games, however, things are not rotating all the time. I'm not sure the rotation is the core gameplay. I doubt it. I think the limited air and the length of the air pipe is a good idea, and also the maze that things create in such a crowded space (space as in galaxy). Also the lack of violence, which make the game suitable for all ages (mucho more with those nice graphics!) Of course, it's up to you :)
I'd like to fix this problem if we do a future release at the moment though we don't have anyone on our team who has a problem with it. That makes me wonder whether (in addition to the excellent points made above) experience with the control of the game helps. Once you have a feel for how to control your angular momentum you possibly feel less off-balance.
@Chard: Perhaps all of you have good displays? I read somewhere (can't remember where, so perhaps I am talking nonsense) that the display quality and refresh rate influenced the feeling of motion sickness and headaches while watching flashing/moving graphics
My display is fine. Heh I'm thinking of hacking the game so the camera won't rotate, just to see how different it plays. That is, if ya'll don't mind.

Hmm... certainly not all our screens were that good...

@pymike: The critical lines are in lib/game.py in the GameMode class. You need to ensure that you reposition the view in the middle of the screen. There's a glTranslate at the start of on_draw as well as the glRotate and the self.world.background.draw line. Also some magic constants in inv_camera_transform need adjusting. I'm not certain that's everything but it might help.