• DaMonsterKnees@lemmy.world
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    5 days ago

    Fuck, this is a thing in ksp and for the life of me, I can’t remember the term. Instead of asking the global brain, I came here to say, I hope you have a good day.

    • Kraken is the term.

      Krakens are physics glitches which generally get worse the deeper into space you are. Some craft are designed to be 100% kraken powered and don’t even have engines onboard

      • sp3ctr4l@lemmy.dbzer0.com
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        5 days ago

        Its… a bit more complex than this… but basically, the reason why the simulation tends to act more insane the further out in space you are, is because of you are getting closer to the limits of floating point data type precision used for location coordinates.

        Literally the simulation error becomes greater and greater the more extremely distant you get from the world origin point, basically the rounding errors get worse.

        You end up with different parts of what is supposed to be one big connected thing… having different amounts of error applied to them, to their locations… so your craft will tend to… lose local relative spatial coherence, then the constraints in the physics system try to react to this kind of error by pulling or pushing things apart, then that calc also suffers rounding errors, then this all starts an uncontrollable feedback loop and runs away into an angry ball of madness convulsing and whiplashing at seizure inducing levels.

        I remember switching from 32 bit KSP to 64 bit KSP significantly allevisting this problem, way back in the day.

        But you are also correct that many things are designed to kraken at basically any distance near or far, and… mostly this is done by intentionally utterly overwhelming the physics engine with waaay too many concurrent collisions or elastic connections to attempt to process at the same time, but there are also a bunch of other ‘wierd tricks’ that … basically are ‘Super Effective’ against peculiar weaknesses of the physics engine.

        This is why there are mods that do things like simplify various parts (usually very small ones) down into just having a totally perfect, non wobbling, non elastic connection to their adjacent parts, to reduce the overall physics compute cost.

        Also, just generally, game engines tend to have a hard time with rotational momentum in 3d, as compared to lateral translations in 3d… especially when an object … or conglomerate object… does not have its weight uniformly distributed.

        You wanna make a game physics engine cry?

        Try spinning (extremely fast), that’s a neat trick!

      • toynbee@lemmy.world
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        5 days ago

        Interesting knowledge for an optician.

        I’ve known astrophysicists who played KSP who wouldn’t have known that.

          • toynbee@lemmy.world
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            5 days ago

            Dang, I think my highest time on steam is Eve with something like 1800 hours. (I’m not sure if there’s a way to track how much time I’ve spent in Minecraft or classic Everquest (given that I no longer have a subscription to the latter)).

    • Asweet@lemmy.ca
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      5 days ago

      It’s using an engine that is purpose built for the task, so I don’t think it will have the same kinds of issues. Perhaps some brand new FUN ones though!

      I believe one way it gets around at least one of the kraken sources is by always having either your vessel or your point of view at the center of the “universe”, and having everything else move around that. That way the floating point precision isn’t really a problem, as the things that are far enough away aren’t likely to be simulated to the point where the errors would have an effect. Could be wrong about this though.

      • Olgratin_Magmatoe@slrpnk.net
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        5 days ago

        No, you’re definitely right about the simulation/floating point thing. They seem quite proud of it for good reason.

        But that doesn’t mean other fun bugs can’t happen >:)