Recognized by Council Relativity and ship speed limits

[Auriga_Nexus]

Now that we have rails and whatnot, I've seen a lot of people using catapults and docking collars, it kinda makes me think of the move Interstellar. But while we're on the subject, there should be some major changes as to how ships fly.

Now I can understand the need for a speed limit, but to be honest even on servers with true Newtonian physics it doesn't feel like it because you still can't exceed the speed limit when your thrusters are on. Case in point, this one time on ElywnEternity, I warped into a wormhole sector and was trying to fight my way out of it, and I had the idea of moving at an angle from the line between the singularity and my ship, going with the WH's gravity and using it to slingshot myself past the singularity and into the next system over rather than going away from the center and fighting the gravity the whole way. However the speed limit on EE is a measly 150 m/s, and even if I'm going along with gravity, the way thrusters work means that even if I'm going full throttle and the combined forward acceleration of my ship and the pull of gravity exceeds that value the game will still limit me to 150 m/s. And that's just plain stupid, especially considering if I let my engines idle and let the wormhole pull me in, I'll often be going 1000 m/s or higher by the time I hit the event horizon regardless of server speed settings.


So based on that, I've come up with an idea on how to change the way propulsion systems work with the game's physics, one that more closely mirrors actual spaceflight while still allowing a sort of limiter on speed to maintain server functionality.

The idea is based on the concept of relativity. In our universe, the absolute limit for any object of nonzero mass is 3.0x10^8 m/s, also known as c or the speed of light. According to the theory of relativity, an object's mass increases exponentially as it approaches the speed of light, and as the mass increases, the amount of energy needed to accelerate the mass to go faster increases exponentially as well - and any object of nonzero mass would require an infinite amount of energy to even travel AT the speed of light, let alone exceed it. This phenomenon is called the "Lorentz transformation", and is represented by the following equation:

m = m0 /sqrt (1 - ((v/c)^2))

where m is mass of object
m0 is mass of object at v=0
v is velocity in m/s
c is speed of light (3.0x10^8 m/s)
sqrt(x) is the square root of x (since I can't use a root symbol)

Now this is my idea: rather than setting an absolute speed limit for ships on the server... why don't we let the server speed limit represent the "speed of light", and have a ships mass and thrust determine their max possible velocity using the Lorentz transformation?

For example, my TSAB Striker MK V has a mass of approximately 1000, and the thruster system puts out around 2000 thrust, for a total of 2 m/s squared acceleration, which remains constant up until I hit the server speed limit of 300 m/s, at which point it drops to 0.

Now lets assume that we change the physics model to where the server speed limit actually represents the speed of light, and use the Lorentz transformation as our ship's effective mass when calculating thrust.
It's a bit of a complicated calculation, so to simplify I created an Excel table showing the ship's effective mass, acceleration with 2000 thrust at that mass, and the amount of thrust required to maintain a constant acceleration of 2 m/s^2, starting at a velocity of 0 (at rest) and incrementing by 10 m/s until reaching 300 m/s. These charts show how the mass and the thrust required for constant acceleration increase, while the acceleration at a constant thrust of 2000 decreases, as my ship approaches the 300 m/s "speed of light":



As you can see, there is not a significant change in mass until you start getting around 100 m/s, or 1/3 the speed of light. At 200 m/s. the effective mass of the ship is now almost 1.5 times its mass at rest. At 260 m/s, the mass has doubled. At around 272 m/s, it has tripled, and at around 290 m/s it has quadrupled. You'll notice that the graphs for mass and thrust do not include a value for 300 m/s; this is because the chart values are assumed to be zero because the cell value the chart is reading is undefined, this is because Excel is throwing me a divide-by-zero error for those cells. In other words it becomes impossible to exceed 300 m/s. It is the effective speed of light.

Now obviously the other things related to relativity - length contraction, time dilation, etc - are much too complex to be implemented, and even if they were they would only make things more difficult for the players. However, if we implement the laws of relatively purely in regards to mass and acceleration, we can achieve basically the same thing achieved by the server speed limit, but in a much more realistic manner. Keep in mind that as the ship goes faster its mass increases, and as the mass increases so does the inertia - meaning it will be that much more difficult to stop. Even on servers without true Newtonian physics, we could make the friction coefficient a force rather than a rate of deceleration. In other words, if you are traveling at 200 m/s and the friction coefficient is the default 5%, rather than decelerating at 5 m/s^2 you would have a 5 N force applied in the opposite direction of your movement, and since your effective mass is higher the force of friction would actually be lower. In this way the effects of friction would actually effect ships more moving at a slower speed; as speed increases the force of friction increases at a linear rate but the effective mass increases exponentially.

Now regarding gravity (and this is where things get fun), I'm going to say that the force of gravity acting on a ship is determined by the ships actual mass pre-Lorentz transformation, and not the effective mass. Why? Because the Lorentz transformation involves general relativity, where all objects are in a complete zero-gravity environment. However, if you are within the gravitational pull of a planet, star, or wormhole, and are not moving even as the gravity pulls you in, then even though you are moving relative to the universe as a whole, relative to that gravitational field you are NOT moving. This is why certain things related to gravity ignore the laws of relativity - and why it is (theoretically) possible to use gravity as a means of bending space-time and exceeding the speed of light. We think of gravity as a force, but in reality it's more of a shift in the inertial frame of a body at rest. This is why an event horizon exists around a black hole - the inertial frame of the black hole's gravitational field is such that a body at rest is in reality moving toward the singularity faster than the speed of light, and attempting to fly out will result in the mass of the ship increasing infinitely as you approach the speed of light relative to that inertial frame, preventing you from moving faster, while relative to normal space time you are still moving toward the singularity.

In other words, it is possible to "break" the server speed limit, but only in a wormhole. Of course with careful calculations and the use of a relativity-ignoring jump drive, it would be possible to break free from the wormholes gravity and fly faster than the speed of light - you would just have zero control over your ship because at that point the amount of acceleration you would achieve from thrust is effectively zero.

Of course, I may be off about how this works, I'm not a physicist after all (that would be my senpai Susan), but it would be an interesting way of managing how ships move, yeah?


Oh and while we are on the subject, someone mentioned in a previous thread about having a kind of "inertial dampener" that could be set to automatically apply thrust to slow or stop a ship. Right now we have that in the form of the shift brake, but this version would turn on automatically whenever you left the ship core or logged out; in other words bumping a ship with no pilot would be the same as bumping a ship where the pilot is holding down the Shift key to slow his ship. This to me would seem fairly easy to implement, and it would solve the BIGGEST problem to running a server with true Newtonian friction=0 physics - the tendency of an object in motion to remain in motion unless acted upon by a force, also known as Newton's 3rd Law. Most servers don't screw with the default setting because if your ship gets bumped and you can't catch it, not only are YOU fucked, so is the server once said ship reaches the effective edge of the universe as defined by the maximum universe size the server can handle before crashing. This would be an effective solution to that problem and may encourage more servers to switch to true Newtonian physics which IMHO was the way Starmade was meant to be played.

 

[ltmauve]

Agreeing with everything except the parking brake. What if I want to walk around my ship or something? More people agree with drag only activating after a collision until the user either attempts to accelerate or the ship stops.

 

[ante185]

Agreeing with everything except the parking brake. What if I want to walk around my ship or something? More people agree with drag only activating after a collision until the user either attempts to accelerate or the ship stops.

http://starmadedock.net/threads/parking-brake-for-unoccupied-ships.7507/
i assume you've seen the thread, but anyways, it comes up with a rather nice idea.

 

[Darkkon]

I like this idea a lot. The "parking brake" idea is actually quite sound because, from an rp view, you need autopilot. Perhaps not while you are actually flying, but you're not going to sit in the pilot chair 24/7 making tiny tweaks with the maneuvering systems to keep the ship in one place. Easier to leave that to the onboard computer.

As for the main part of the idea, I fully support it! Although, including relativistic visual effects would be very cool too, I admit they would be very confusing for a lot of people. Particularly the apparent bending of space when you get close to light speed. And time dilation....although time is always difficult when it comes to gameplay...there's a reason you don't really see multiplayer games with time control powers. (I for one, haven't seen a single one.)

 

[mrsinister]

I like this idea a lot. The "parking brake" idea is actually quite sound because, from an rp view, you need autopilot. Perhaps not while you are actually flying, but you're not going to sit in the pilot chair 24/7 making tiny tweaks with the maneuvering systems to keep the ship in one place. Easier to leave that to the onboard computer.

As for the main part of the idea, I fully support it! Although, including relativistic visual effects would be very cool too, I admit they would be very confusing for a lot of people. Particularly the apparent bending of space when you get close to light speed. And time dilation....although time is always difficult when it comes to gameplay...there's a reason you don't really see multiplayer games with time control powers. (I for one, haven't seen a single one.)

you never seen this? There are some multi-player games out with time effects.

Spoiler

also, a mod for half-life called " the specialist " had time effects as well.

and OP, interesting and creative, how much impact would this have?

 

[Darkkon]

you never seen this? There are some multi-player games out with time effects.

Spoiler

also, a mod for half-life called " the specialist " had time effects as well.

and OP, interesting and creative, how much impact would this have?

Okay, i really want that game now. And no, I have never heard of it. My point still stands though that creating the time dilation effect of relativity would be rather hard to code into Starmade. I still would love it if it actually happened though. ^_^

 

[Auriga_Nexus]

you never seen this? There are some multi-player games out with time effects.
also, a mod for half-life called " the specialist " had time effects as well.

and OP, interesting and creative, how much impact would this have?

Regarding time effects in multiplayer games, one major one I can think of is the time dilation effect in EVE Online, but that has less to do with relativity and more to do with helping the servers keep up with combat calculations during massive nullsec fleet fights. With that effect the server time remains the same, but any actions your ship takes are slowed by a certain percentage, from movement to firing cycles to lock time.

However, the difference with EVE's timey-wimey stuff is that it affects all players equally across a given number of systems, whereas this effect may differ for people in the same sector, and there's no real way to simulate that effect unless you apply it equally to all objects. So true time dilation is not really viable. Visual effects such as tunneling and length contraction may be possible however, to give the player the feeling they are traveling at relativistic speeds.

 

[mrsinister]

Regarding time effects in multiplayer games, one major one I can think of is the time dilation effect in EVE Online, but that has less to do with relativity and more to do with helping the servers keep up with combat calculations during massive nullsec fleet fights. With that effect the server time remains the same, but any actions your ship takes are slowed by a certain percentage, from movement to firing cycles to lock time.

However, the difference with EVE's timey-wimey stuff is that it affects all players equally across a given number of systems, whereas this effect may differ for people in the same sector, and there's no real way to simulate that effect unless you apply it equally to all objects. So true time dilation is not really viable. Visual effects such as tunneling and length contraction may be possible however, to give the player the feeling they are traveling at relativistic speeds.

Interesting, ....as with the half-life mod, it used a sphere of influence around the player, anything in that area would slow allowing the player to move around bullets or missiles, jump over others, etc....and anything outside the area would look like he is moving normal but dodging whatever was thrown at him/her or in their way.

 

[whooplaah]

I say we revisit this idea after Astronaut mode is expanded. If you want to simulate time dilation, one way would be to adjust hunger meters, durability/decay of items/food/gear, growth/death of flora/fauna, or something similar. We might even build a space-fridge: it prevents decay by storing your potatoes at near light-speed.

I disagree with breaking the speed limits on servers. Those exist because the machine can't handle the calculations of objects moving too fast. It is a physical limitation from the real world, one that keeps the virtual universe from collapsing. If you break that barrier with too many objects, it could cause the virtual universe to crash.

If you implemented a way to break the server speed limit, it would just result in servers lowering the speed limit so that the new broken speed limit is manageable by their machine.

 

[lupoCani]

I say we revisit this idea after Astronaut mode is expanded. If you want to simulate time dilation, one way would be to adjust hunger meters, durability/decay of items/food/gear, growth/death of flora/fauna, or something similar. We might even build a space-fridge: it prevents decay by storing your potatoes at near light-speed.

I disagree with breaking the speed limits on servers. Those exist because the machine can't handle the calculations of objects moving too fast. It is a physical limitation from the real world, one that keeps the virtual universe from collapsing. If you break that barrier with too many objects, it could cause the virtual universe to crash.

If you implemented a way to break the server speed limit, it would just result in servers lowering the speed limit so that the new broken speed limit is manageable by their machine.

Did it ever strike you that this suggestion does include a way to limit speeds, but in a more natural-feeling fashion instead of a hard-cap?

 

[Auriga_Nexus]

Did it ever strike you that this suggestion does include a way to limit speeds, but in a more natural-feeling fashion instead of a hard-cap?

I think he's referring to my thread about using wormholes as a way to slingshot yourself into FTL by crossing the event horizon and then jumping out. He's right though that may make things too difficult.

Though a decent application of something like this would be something along the lines of an Alculbierre drive (http://en.wikipedia.org/wiki/Alcubierre_drive), that would let you travel along a calculated straight line at faster than the speed setting (hereafter referred to as "server lightspeed". Of course, these would have a hardcap which determines the maximum speed you can achieve in warp. So a server could have a setting in the config file SERVER LIGHT SPEED=300; WARP DRIVE MULTIPLIER x3, where c/speed of light is 300 m/s, and a warping ship can travel at an FTL factor of 3 or 900 m/s.

Also LupoCani keep in mind if an astronaut is traveling at relativistic speeds, then for the most part they function the same - its the universe around them that slows down or speeds up. Case in point in the movie Interstellar when they go down to that planet that was close enough to the wormhole to induce time dilation? The away party was on the surface for about 2-3 hours, but when they got back to the main ship 27 years had passed.

So traveling at relativistic speeds would do nothing for your hunger meter or whatever, it would just mean things around you go by faster - and there's really no way to simulate that in a multiplayer setting, at least not that I am aware of.

 

[Megacrafter127]

it would just mean things around you go by faster

No, they would go by slower(from your own perspective), while the outsider would see you go slower. t(relativistic)=t(newtonian)*sqrt(1-v²/c²)
Who moves and who doesn't does not matter, as speed cannot be determined as an absolute value, only relative to another entity.
(Anyhow, I am just nitpicking)

 

[Auriga_Nexus]

No, they would go by slower(from your own perspective), while the outsider would see you go slower. t(relativistic)=t(newtonian)*sqrt(1-v²/c²)
Who moves and who doesn't does not matter, as speed cannot be determined as an absolute value, only relative to another entity.
(Anyhow, I am just nitpicking)

Oh yeah, I forgot. Friggin Twin Paradox...

 

[NeonSturm]

No, they would go by slower(from your own perspective), while the outsider would see you go slower. t(relativistic)=t(Newtonian)*sqrt(1-v²/c²)
Who moves and who doesn't does not matter, as speed cannot be determined as an absolute value, only relative to another entity.
(Anyhow, I am just nitpicking)

For accelerating 1kg 0->1 m/s, you need 10 Newton.
For accelerating 1kg 1->2 m/s or 2->3 m/s, how much force exactly do you need?

If equal, you could go unlimited speed.
If more, shouldn't you be able to measure your absolute speed by measuring the difference?

Ship at 100m/s
Ship-part from 100m/s to 101m/s
required force can be used to measure absolute speed

And I haven't heard of anything like this yet.

Also it would mean that a fast-spinning wheel has more mass, thus allow inertia-drives

v=0->1 : -1mv(xy) -- start spinning
v=1->1.4 : -2mv(z) -- start moving
v=1.4->1 : +2mv(xy) -- stop spinning
v=1->1 : +1mv(z) -- sop moving
v=0->1 : +1x mass*velocity² -- start moving opposite
v=1->0 : -1x mass*velocity² --- stop moving opposite
[repeat]
difference:

-1mv(z) and +1mv(xy) for the carrier​

but doing the same with counter-spinning wheels, where +1mv(xy) and -1mv(xy) cancel each other out:

-1mv(z).​

If you keep velocity and gravity only affects the reference frame, why does it not cancel out and let you stay mid-air?

Gravity either accelerates you,
or you hook into new points of reference changing your velocity by the difference in these point's movement difference at the re-hook time.​

 

[Megacrafter127]

For accelerating 1kg 1->2 m/s or 2->3 m/s, how much force exactly do you need?

The strength of the force only determines the time it takes to perform the acceleration.
I can accelerate an object of 10kg with a force of 0.1N by 1m/s, it would just take 100s to do so.
dv/dt=a=F/m
Also, if I were to accelerate an object from 0c to 0.1c, and continue accelerating using the same force, the acceleration decreases, as the mass of the accelerated object increases.

 

[NeonSturm]

I can accelerate an object of 10kg with a force of 0.1N by 1m/s, it would just take 100s to do so.

Make your life a bit easier and think about speed changes in just 1 second.
Then you will have a variable less.
​

 

[whooplaah]

Did it ever strike you that this suggestion does include a way to limit speeds, but in a more natural-feeling fashion instead of a hard-cap?

Yes. Ergo:

If you implemented a way to break the server speed limit, it would just result in servers lowering the speed limit so that the new broken speed limit is manageable by their machine.

To rephrase what I said in that post:

Imagine we have a server with the setting: Max Speed = 200 m/s

The OP want's to break this barrier using gravity fields because that's how science works. The game introduces a separate property: Max Gravity Sling Speed = 300 m/s. However, the server still has to use the same physics algorithms and still has the same amount of RAM to dedicate to those calculations, but now those calculations are larger and have to be done more often. Anytime a ship does a gravity sling the server starts to lag because it can't handle objects moving faster than 200 m/s.

A server owner wants to avoid lag. Therefore they go to the CONFIG and set Max Gravity Sling Speed = 200 m/s because that is all the machine can handle. But now we don't want for the gravity speed to be the same as the speed achievable with engines alone. Therefore we have to set Max Speed = 150 m/s to preserve the goal of the OP.

Ergo:
If you implemented a way to break server speed limits, it would result in servers lowering the speed limit so that the new broken speed limit is still manageable by their machine.

That's why the FTL/Jump Drive teleports players rather than increasing their speed.

 

[Megacrafter127]

Spoiler: rant

Make your life a bit easier and think about speed changes in just 1 second.
Then you will have a variable less.​

What is that 3D-model you attached supposed to mean?

Even if we say dt=1s, it still changes not much.
The velocity of an object is determined by the amount of kinetic energy it has, and it's mass.
E(kin)=0.5*m*v² → v²=2*E(kin)/m
By accelerating an object, all we do is add kinetic energy to it.

Problem is, the faster an object is, the larger will its mass become, hence adding more kinetic energy to it will result in less speed-increase.
m=m0/sqrt(1-v²/c²) | m0...mass if v=0
If m0 isn't 0, and v→c, m is infinite, thus applying any finite force has no effect anymore.

NeonSturm for the sake of this thread, let's take this to a pm if any more questions/doubts remain.

 

[snowhusky5]

I think OP has a reeeeally great idea. Even if the game doesn't handle the max speed as 'light speed,' a speed limit that is rarely reached would be infinitely better than the current sudden-stop one. This could be implemented by increasing mass exponentially to infinity (decreasing an acceleration multiplier to almost 0 would be easier from a game engine standpoint) as speed increases. It could be both realistic and rather interesting, since deceleration would be decreased as well. It would also allow all ships to reach 'max speed,' even if ships with a smaller thrust:mass ratio took ages longer as mass got real big, and because deceleration is decreased as well big ships would get an approximate max effective speed (decided by the judgement of whoever's flying it), since they wouldn't be able to slow down quickly once they got going.

As for the parking brake, its probably a necessary evil. Optimally, it would only turn on automatically if no life-signs are detected nearby, or if a collision happens. Even the no-life-signs bit could be turned on or off, if your position was saved relative to the ship rather than the universe, so you logged back in into it even if it moved.

 

[Valiant70]

I'm going to have to give this thread a bump. I was thinking about this this morning, and I wish the game handled speed limits this way. It means ships with high thrust-to-mass ratio can realistically make use of higher speeds than ones with lower thrust. That translates into thrust having a practical impact on speed, but not an unrealistic forced effect with some kind of magical friction in vacuum. Also, remember that it takes longer to slow down from high speeds, not just longer to reach them.

Since overdrive doubles speed limit, it would make sense to treat default speed limit as half of light speed. In other words, it doesn't take you an hour or so to squeeze out the last 0.1 meter per second of speed. In sci-fi jargon, you could say hardwired safety limitations prevent going beyond 0.5c (half of light speed) without a device to correct relativity effects (overdrive). With overdrive, you can reach light speed, but only experience the relativity effects of going half of light speed.

We can't simulate time dilation in a multiplayer game, which is okay, but it might be fun to add that in as an option for single player... later.