Besiege V 0 2 steam physics weirdness

Having previously defended steam cannon physics from comments originating on Reddit that they are 'nerfed', I have reluctantly come around to the conclusion that they currently have so many issues that it simply isn't worth designing new steam-powered machines. As an illustration, see this video:


This bizarre behaviour makes designing anything steam-powered (except by direct impulse) an exercise in fighting against the bugs, rather than engineering. Not fun. And then there is the odd 'scramjet' behaviour seen when steam cannons get above a certain speed. Fun to exploit if you want to create a rocket, but a damn nuisance if it occurs accidentally in a device supposed to use steam in a more plausible manner. To my mind, such erratic and counter-intuitive behaviour seriously detracts from the potential that Besiege has offered since the V 0.2 update. We now have the opportunity to build complex designs - but anything steam powered is going to be so hit-and-miss in regards to its performance that it isn't going to be worth the effort. Accordingly, I have to suggest that the developers need to take a long hard look at the physics of steam (and water) modelling, and decide whether they want to include something which is so wildly erratic. To my mind, at the root of Besiege should be an attempt to model 'proper' physics - simplified certainly, and with some hand-waving magic as far as say where the water/steam is actually coming from, but plausible in as much as it can be - and anything which introduces random unintended behaviour at the physics emulation level runs counter to what Besiege is trying to be. Whether the developers want to describe the current behaviour as 'a bug' or not is up to them - but it has to be seen as a net negative, and needs further attention.
Actually I've just discovered (as the result of a comment by IceFog72 on the Steam Besiege forum) that I had the gear ratio too low - it will actually move quite a bit faster with 1 to 1 gearing between the crankshaft and the wheels. It was originally geared down as I wasn't getting enough torque to move it under previous Besiege versions. It now moves at a respectable speed, though I suspect that it would still go faster with the rear steam cannons removed and the drive train disconnected...


Staff member
Hmm, on a different thread it was discovered that shooting a car with the steam is faster than using the steam for propulsion, may that be part of the reason too?
Yes, it is certainly further evidence that something is wrong. There is no way I can think of in real life where the force exerted on an object being hit by steam from a vent can exceed the force exerted on the source of the steam by the steam being expelled. It is certainly possible for a vehicle to be propelled forwards by deflecting the steam from a forward-facing source off something (think of a thrust reverser as used on a jet engine), but it should move slower, not faster than using a rear-facing source. This is basic Newtonian physics: F=ma.


Staff member
Oh, well, for regular water I think they did it on purpose, since fun game-mechanics and such.

And I think you rather should reference to "For each reaction there is an equal and opposite reaction" than F=ma.
That said, there's a lot of stuff in the game already that doesn't follow that principle :p