The Greatest 'Cheat' To Ever Plague Quake Engine Games, Explained

Anyone who's played an old-school shooter based on id Software's more ancient engines will be familiar with a technique — or cheat, depending on your perspective — called "bunny-hopping" or "strafe-jumping". The idea is that, using certain mouse / keyboard inputs, you can continually increase your speed, outrunning your opponents (and fellow teammates). But why does this feature exists and how does it work? It's video explainer time, folks!

Quake 3 is used to show off the problem, however, as the video mentions, the issue can be exploited in many games based on earlier id Tech-based games, such as the original Counter-Strike.

So, why is bunny-hopping / strafe-jumping a thing? It comes down to the physics code, unsurprisingly. Don't worry, there's no need to be a maths master to understand what's happening.

Image: Matt's Ramblings / YouTube

Basically, the player's intended direction, determined by keyboard and mouse inputs and the current direction, are added to together. This final, three-component vector (x, y and z) is not normalised, so its possible in some cases for these components to have a value greater than one.

I'm sure you can see where this is going: as long as the player's movement continues to add to their velocity, it's possible to go faster and faster.

This is a very basic explanation — for example, I haven't talked about why the player's movement isn't just capped — so check out the much more detailed video. It also includes pictures, which are always helpful.

Strafe-jumping physics explained [YouTube]


    "cheats" like this were never originally intended to be created in the first place and once mastered made them special and satisfying to the game itself. Starsiege tribes and skiing is a good example of this and the devs ended up added it into the 2nd release of the game.

    Modern games seem to find and exploit and they are simply patched out and never seem to evolve in their own way yet its funny how devs try and create a new gameplay style pre release and you end of ether loving or hating it which massively devides sales.

      Melee jetpacking in no mans sky is one of these things, but they left it in.

    The fact that you call strafe jumping a cheat shows just how little you have played Quake or other Arena FPS genre games. Strafe jumping was an accident in Quake 1 but it has been intentionally put in every other Quake since because skills-based movement adds a very desirable element to the game and it is considered the norm. All other non id-tech games go out of their way to add this type of movement. Quake Champions, the latest installment, doesn't actually even use an id-tech engine and has had strafe jumping added in on purpose.

    Made an account literally to upvote Jimmy's

    X-quakeworld fanatic n I'd fan ... Jimmy gets it!

    Now my longtime Kotaku anonymous creeping is over :'(

    lol, strafe jumping is cheating?

    theres a difference between cheating and skill.
    Cheating would be used a hack or modifying something.

    strafejumping just shows how deep carmacks code was to even be able to pull off stuff like this.

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