newtonian physics? sure hope this is a bug

[elthore]

As far I understand, Newtonian physics includes the theory of gravitation F=G(m1m2/r2). This is definitely not the formula being used in evochron, its not even close, intentional or bug?

Proof:
In game, one can take the starting ship and equipment to 500km altitude above erato2. Then begin traveling anywhere between ~90 to ~300(m/s?) perpendicular to the force of gravity and maintain constant altitude by only adjusting pitch. So the attitude of the ship is actually changing the force of gravity upon it with IDS disabled. The gravity readout appears to change as well but this seems to actually CHANGE gravity.

As it is right now in version 2.308 of Mercenary, the physics is not Newtonian. =(

[Vice]

As far I understand, Newtonian physics includes the theory of gravitation F=G(m1m2/r2). This is definitely not the formula being used in evochron, its not even close, intentional or bug?

Proof:
In game, one can take the starting ship and equipment to 500km altitude above erato2. Then begin traveling anywhere between ~90 to ~300(m/s?) perpendicular to the force of gravity and maintain constant altitude by only adjusting pitch. So the attitude of the ship is actually changing the force of gravity upon it with IDS disabled. The gravity readout appears to change as well but this seems to actually CHANGE gravity.

As it is right now in version 2.308 of Mercenary, the physics is not Newtonian. =(

Two points to consider with those systems:

1 - The gravity gauge is not a static force factor indicator (ie not limited to only a base gravity equation). It's a dynamic indicator that displays the overall force offset being applied to your ship. So it will take into account relative factors such as thin upper atmosphere lift. So gravity isn't changing, but its overall effect on your ship can and the gauge will display the latter rather than the former.

2 - Planets are handled uniquely in terms of gravity effect. They are credited with an atmospheric value that can offset the force of gravity relative to your ship's speed and orientation. This is a factor that is not applied to objects that lack atmospheres, such as stars and black holes. So the behavior you see is unique to planets in that regard.

[PlasmaJedi]

It isn't TRUE Newtonian, but the point is that ships don't bank and turn like they are in some kind of atmosphere when in the vacuum of space. This makes more interesting and challenging space combat, and is different than most games out there.

But, you are correct, the gravity simulation is not accurate... at all... I'm sorry Vice.

Gravity is not a force of acceleration, but velocity. Plus, the reading of the speed in your cockpit is only forward speed, not overall speed. Get going at 1000, then tilt 90 degress up, and speed = 0. Add these together and you can do some crazy stuff.

Perfect example: There is a device that lets you gather fuel from a star's corona (an atmosphere, technically, but your ship will not 'fly' in it, like on a planet) or from a nebula. But a star corona is the easiest place to get fuel since it doesn't stop you from hyperjumping out when done; nebulae do.

To gather fuel, a great tactic is to hyperjump very close to the star, lock your collector beam on, and rotate away from the star. You may be falling fast toward the star by now, but fret not. You can judge your 'true' speed by watching the particles of space dust wizz past your ship. They are always stationary. The gravity rating is how much velocity the star is acting on your ship, NOT acceleration. Rotate normal to the star, then set your speed on your IDS equal to the gravity rating. Eventually, you will come pretty close to stopping, and your main engines will IDLE.... Yup, turn off, and you will be hovering in the gravity well of the star. You can do this with inertial mode as well, just it'll take some effort to get it right.

This works on planets, moons, and black holes, but in the atmosphere of the planet, the 'friction' of the air may 'slow down' your hover.

I'm not sure if this is a physics manipulation or Vice's intended trick, but another little oddity about atmospheres: You can scream outta the black of space far faster than the ~1470 atmosphere speed limit, and survive simply by rotating with your bottom toward the planet. Don't even need IDS. Your forward speed indicator should show less than the limit, but your actual speed can be much higher. You'll slow down nicely, making a gloriously flaming entrance!

Another non-Newtonian slip, missiles have a top speed, and so apparently do ships, altho ship's speeds are much higher. With IDS off, its very easy with a ship of any class to outrun just about any missile. And shooting a missile at ships chasing you means it'll hit them faster, likely before they can react, but if you're chasing, you better be at close range or using a fast missile.

EDIT: The fuel collecting trick I described is particulalry fun if your in combat. The gravity gage is a good measurement of how close you are to death. You can safely get to where the gage reads ~1100, and any closer, ~1200+, and you're likely to slip too far and esplode! The fun part is, at this range, AI cannot deal with that kinda gravity, and fighter and even CRUISERS will fall into the sun and explode! I once had a contract to spy on a cap ship while we battled close to the sun. I didn't realize just how close we were, but I did know we were falling. Thanks to my cloaking device, I hid quite well under its belly, and just as the scan completed, the cap ship BLEW!, and then so did I! Darnit! Didn't even have time to quicksave!

[Edited on 2-8-2013 by PlasmaJedi]

[elthore]

500km is at an altitude above the atmosphere as stated by the game. The zone inside of the 'gravity field' but above 'entering atmosphere'. You are saying even at that point, there are atmospheric effects? Ok that makes sense.

Yet the way gravity is handled even if we only consider it one directional, ship being affected by the planet and not the other way around, is still either very buggy or intentionally not Newtonian.

A circular orbit(theoretically, since its near-impossible IRL) at a specific altitude for an object of a certain mass CANNOT be attained by a range of speeds depending on orientation. Perhaps I failed to explain myself properly but if you go in-game and try this you will see. There is either a bug somewhere or your formula of gravitation isn't anything close to resembling F=G(m1m2/r2). Force of gravity in-game can go from nil to full force as the ship's orientation(pitch up/down) changes. Upper atmospheric lift can ascend air pockets, this is due to convection and pressure changes, but I don't believe that it can send a slow flying ship into space. Perhaps it is the atmospheric formula that needs to be reassessed so gravity function properly(when it should).

Dont get me wrong I enjoy your game and have purchased 2 titles as well as encouraged friends to play.

[Zach]

I think maybe we are being over-serious when we don't really need to be.

It is after all a game, and perhaps certain concessions had to be made, for things to work the way they were intended, or because of they did work exactly the way they should - it would be no fun for the players?

[Marvin]

Gravity is not a force of acceleration, but velocity.

G = 32 ft/sec squared. Approximately. Squared.

[PlasmaJedi]

It all depends. I personally wouldn't mind seeing gravity use acceleration, which is realistic. You could actually enter orbit, and hovering by a star would burn fuel, adding more reasons to carry a fuel converter for sun ops, etc. But maybe Vice has tried this and doesn't want to.

Oh, btw, stars are really tiny... Just saying.... Planets are huge compared to stars. But that's really just fine. They make it feel like they are so far with the blinding light, you can't see just how close you really are.

BTW, can you collect anything near a black hole? How about Anti-matter? Wouldn't that be cool, Vice?

EDIT: I hope you know, Marv, I meant in this game, its done by velocity. In the real universe its an acceleration. To hover in the real universe, you must apply an equal force, not velocity, to counter gravity, which means you must constantly run your engines.

[Edited on 2-8-2013 by PlasmaJedi]

[SeeJay]

I know 1 thing you can collect near a black hole!

A lot of body parts from pilots trying to jump through it! LOL!:P

[Marvin]

[PlasmaJedi]

I know 1 thing you can collect near a black hole!

A lot of body parts from pilots trying to jump through it! LOL!:P

Funniest joke of the day! XD

<blip-bloop> Achievement Unlocked!



Another EDIT: I kinda hope Vice explains why he used velocity to simulate gravity, rather than acceleration. I'd take testing and lots or work, but I'd love to see a accel-based version, but of course, there may be other consequences to that so maybe its best left alone.

[Edited on 2-8-2013 by PlasmaJedi]

[Vice]

It is after all a game, and perhaps certain concessions had to be made, for things to work the way they were intended, or because of they did work exactly the way they should - it would be no fun for the players?

Indeed, it's not designed to duplicate accurate gravity, being more 'game' than strict physics simulation in that regard. But it's something I can likely dig into to move it more towards realism, if enough players think it's important enough to spend the time to work on it to change it.

If so, please send me some feedback via e-mail (starwraith.com > contact) and in particular, include what gameplay benefits you think changing the gravity system would provide.

[PlasmaJedi]

That would be very interesting, but since this would not be a small change, is there a way to release a beta edition, in case it didn't work out? I think we need to establish that possibility before we get too hyped up on 'realism'.

Of course, what we'd lose is this:

Ability to 'hover' without burning fuel, ideal for coronal refuels.
Suddenly stars and blackholes may become far more dangerous!
Ability to stay 'in sync' with stations/carriers parked near gravity wells
Ability to leave a planet's atmosphere with the small amount of fuel we spend now.


We'd gain this:

Ability to theoretically enter a 'parking orbit' around a planet, and literally circle it with engines off.
Depends on how large and strong the well is. If we hit atmosphere, we'll slow and fall. Depending on what values are set, you could have it required to move faster than 1400 to maintain orbit, and thus have the need for re-entry maneuvers (slowing down, aligning the ship for re-entry, as described above)

Ability to slingshot your speed with a string gravity well, like a blackhole or star (this can be done with planets in RL, but I wouldn't make their wells big enough for it, as stations and other objects are placed so close to them.)

Ability to re-program the IDS to not IGNORE gravity speed as it does now (Your instruments cannot tell you a gravity well is pulling you at x speed), but now enable it to attempt to compensate for the pull, meaning it visually behaves normally in a weak field, but burns fuel keeping you stable, and in a strong field, struggles to fight it, burning more fuel.
This could be used to simulate the 'sync' trick with carriers and stations in wells, as if the well is weak, setting the IDS to 0 will ACTUALLY stop you, but keep thrusting to keep you there. This will make near-solar battles very tricky, and possibly impossible for the AI.

Enable fun games, such as firing dumbfire missiles across a planet, attempting to hit a city or continent, or instead thrusting and using inertial mode and do it with one's own ship!


Well, if it's possible to do a beta, it would be worth giving a shot, IMHO. But it's your game, and your work, Vice, all up to you.

[-splosives-]

The gravity is entirely inaccurate in Evochron, and so is the rest of the game.
Planets don't orbit
planets are way too small (even after the update)
stars are smaller than planets
gas giants are smaller than normal planets
gravity (as stated above)
there's a maximum speed
missiles don't more at speeds relative to your own, but rather at fixed absolute speeds.
Etcetera.

But I have yet to see a good space sim that does have all these things correctly.
At least Evochron has the inertial movement thing down.

[PlasmaJedi]

The gravity is entirely inaccurate in Evochron, and so is the rest of the game.
Planets don't orbit
planets are way too small (even after the update)
stars are smaller than planets
gas giants are smaller than normal planets
gravity (as stated above)
there's a maximum speed
missiles don't more at speeds relative to your own, but rather at fixed absolute speeds.
Etcetera.

But I have yet to see a good space sim that does have all these things correctly.
At least Evochron has the inertial movement thing down.

That it does. I wouldn't think some of the interplanetary stuff should be done, but basic gravity for ship-to-planets would be cool. Due to the way the Evoverse is set up, moving planets, making stars and gas giants truly massive, would mess things up.

[elthore]

I thought people who played Evochron wanted the realism, or else there are a thousand other space games they could be playing.

I play EM because its the most 'realistic' space game out there and am only offering my input to make it better, not to degrade it in any way.

Its understandable that we cant model 3-body gravitation real time in a game such as this, but whatever formula is being used at the moment must be more complicated than F=G(m1m2/r2). We can easily negate the force the ship exerts on the planet and assume a uniform mass for all ships to simply it even further. As long as gravity pulls towards the center of a planet at a constant force at constant distances, we will have a much more realistic representation of gravity. It would make orbits and slingshots as well as 'dangerous descents' possible.

I dont think that a change towards more realistic gravity, between things that already exert gravity ingame(so, not asteroids or stations) would make the game any tougher than it is now. If gravity starts doing things the pilot did not expect, just IDS. =D

PS i still think there may be a bug here? Maybe whats happening is actually not intended by the devs.

[-splosives-]

If you want realistic gravity, you'll need orbiting stations too, otherwise it would be nearly impossible to dock in one, as you'll be constantly attracted by gravity.

[PlasmaJedi]

It should not be perfect. Really, that'd be too hard. Just make gravity wells short enough that stations are not in it. Thus, one probably wouldn't want to use the REAL gravity formula, but something that fits the purposes, scaled appropriately, etc.

In order to have true realism, EM would need to be totally overhauled. I don't think that's realistic. But the way gravity is done, is very unrealistic. Functional, simple, even a bit fun, just wrong. But since it isn't RL, its EM, it can be whatever Vice wants it to be.

[Edited on 2-8-2013 by PlasmaJedi]

[Triton83]

If you want to test something realistic try this. It's very difficult to create gameplay with such realistic gravity constraints.

[-splosives-]

If you would like to create your own universe with planets orbiting stars and stuff, Try universe sandbox.

[elthore]

If you read the above posts carefully, you'll notice that nobody is asking for completely realistic gravity. Even that simulator isn't absolutely realistic, even what NASA uses isn't completely realistic. Thats why they need to do trajectory correction maneuvers in real life. Calculating 3-body gravity via iteration will give results that are progressively less precise due to the time interval between each calculation.

In my opinion there is room for more realism in Evochron, and this can make it more fun.

[Rubber Chicken]

In my opinion there is room for more realism in Evochron, and this can make it more fun.

Agreed. Not so much to make it so one needs collegiate doctorates and real life pilot's lisences to survive the game, but a little more to experiment with would be really cool.

[Marvin]

If you want realistic gravity, you'll need orbiting stations too, otherwise it would be nearly impossible to dock in one, as you'll be constantly attracted by gravity.

Orbiting stations aside, you can build a trade station close enough to a star for gravity to have influence over your flight path. One such station was built so close that AI, if approaching from the wrong direction, get pulled toward the star and blow up.

[-splosives-]

If you want realistic gravity, you'll need orbiting stations too, otherwise it would be nearly impossible to dock in one, as you'll be constantly attracted by gravity.

Orbiting stations aside, you can build a trade station close enough to a star for gravity to have influence over your flight path. One such station was built so close that AI, if approaching from the wrong direction, get pulled toward the star and blow up.

I know about that one . Why the station itself wasn't pulled into the star is still a mystery.

[Marvin]

I'd like to try building one really close to a black hole.

[_-Caleb-_]

Hola.

In my opinion the whole gain in realism in the simulation.

Battles more complicated, more difficult routes, orbits and size of planets, etc..

Regards!