Is making gravity an element in a science fiction game too hardcore to be playable? One very immersive factor in science fiction adventure stories is gravity. Adventurers deal with the challenge of high acceleration, crushing planets, and zero-G adaptation among different races. I'm wondering how well this factor would translate if you were running your own ship, exploring environments and dealing with traveling the cosmos. Basics The races in the game world rely on either widespread Galactic technology or their own native tech for their hulls. In terms of Galactic technology, billions of years old, gravity is artificial and can even conform to the shell of a given character (read: not a factor). With native tech like that of the various Terran empires, gravity is generated either by rotating segments or a limited form of artificial gravity. Galactic tech is obviously more expensive, while native tech is (in accordance with the storyline and post-apocalyptic environment) more widespread. Here are some gameplay effects and possible challenges: Maps Reconfigured When a native tech ship thrusts, gravity is along the axis of acceleration. This means that walls become floors and ceilings while some cooridoors become drop shafts (down is now sideways). If you had to manuever through the ship while it is thrusting this would change the spatial layout of the ship, potentially becoming very disorienting. Weakening Under High/Low Gravity Native tech ships would coast between thrusting to save fuel. The ship would switch to rotating or using its gravity ducts for the health and comfort of the crew, to perform maintenence more efficiently and to complete certain projects, usually science based. Among civilian passengers and less hardy spacers, lack of gravity would drain morale, which ultimately affects the ship as a business (if taking passengers) and crew retention / obedience. Over weeks, lack of gravity would lower health and stats among all crew. (Long distance trips will be made with time acceleration, btw, depending on the tech level, so this is abstract). As a tradeoff, onboard space could be given over to recreational facilities which fight the effects of low gravity on the heart and other muscle tissues. Under high gravity (such as hard acceleration to make a deadline), crew would tire more quickly. Less labor would get done onboard, accidents would be more devasting, security personnel would be less ready for combat and more instances of fighting might arise. Maximum Thrust and Manuevering This also would mean that ships can only thrust at the gravity tolerable to their weakest crew members. So low-G crew could only tolerate a few multiples of their maximum gravity before blacking out or even dying. (This limit would appear on the interface). This factor then would affect hiring, and better candidates would be more likely to have bionics or cyber enhancements to help them deal with gravity. You could upgrade to equipment to help deal with gravity. Equipment would range from more expensive flight suits (with compression and circulatory stimulation) to fortifying drugs to gravity tanks and gravity stations of compressed fluids. Terrans ships would have an option of two types of reverse-engineered Galactic tech in the form of gravity ducts and gravplates. Ducts would modify gravity in section of the hull (generating a field) but wear down over time and need replacing; plates would require lots of energy per section Tactical Vulnerabilities When thrusting, all crew would respond to an automatic yellow alert and secure themselves and convert the interior. The time this takes would depend on their level of discipline and training. Ships with rotating sections would have to stop rotating to thrust. This time delay would depend on the quality level of the equipment. Both of these states would be represented in the interface as a flashing status effect near/over the acceleration controls. If you chose to accelerate, you'd get a query along the lines of "All stations have not yet reported secure, sir. If we thrust now we may experience __________ effects. Proceed anyway?" The effects might be damaged equipment and/or crew casualties, but would decrease with crew skill (as more experienced crew would learn to grab onto anything). If time critical repairs or emergency surgery were being performed and you wanted to accelerate, the you would have to delay or risk damaging the endeavor (losing equipment or a patient). If a ship's rotating section were hit and disabled, over weeks it would create problems with morale and health. Boarding Defense When boarding an enemy ship or repelling boarders, acceration and reconfiguration of gravity could be a weapon. An accelerating ship could, if all crew were secure, hard accelerate to trap or injure boarders (using the same system as unsecured crew, modified by the equipment being used to board). Gravity could also be cycled (in terms of plates) higher or lower, provided you were in control of the command deck. If you were boarding a ship, you'd either need to be sure the engine was disabled without destroying the ship, or have jet-pack assisted power armor, preferrably with phase-bonding climbing claws. Spinning, Disorientation, Personal Combat, Getting Stuck Under zero-G there are several personal interaction problems: the potential to become disoriented because of physics-based interactions is high. You could jump into a room and hit the opposite wall too hard, or drift at an annoyingly slow pace, possibly even getting stuck in the middle of the room. And in combat, you could be hit and as a result go spinning. For the sake of playability, then, in this case gravity will only be "psuedo-gravity." You can never be sent spinning although you can spin others or have your allies spun if hit. Walls "magnetize" all personnel, causing them to slowly drift toward any wall in zero-G. And while you can still glance off another object, any object you face you "grip" automatically, preventing you from ping-ponging around a room. Obviously, gravity offers some intriguing possibilities in terms of tradeoffs. For a science fiction game, it would almost seem to be required. But since it is so counter-intuitive, it may not be worth it. Thoughts?

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Original post by Wavinator Is making gravity an element in a science fiction game too hardcore to be playable?

For what i read in your post, gravity will impose lots of limits for "low-level" (e.g. in the first hours of the game) players. When the crew is less experienced, they (and also any passenger) will suffer from almost any extreme decision (save fuel, acceleration for the deadline, long travels, sudden acceleration). Maybe this will be OK if you want to use gravity as an indicator of the evolution of your players, but you should balance what low-level players can do. I think... Gravity can be OK if you use it as an element of decision for your players - if (for example) I use more money in increasing the possible cargo of the ship, I'll be more vulnerable against moments of crisis when i have to make extreme maneuvers ("Captain, the pirates are very near, we must accelerate now!" ("Damn, now is when we will miss the gravity stabilizers...")). About boarding and personal combat, depends on how you will design the actual combat.

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When a native tech ship thrusts, gravity is along the axis of acceleration. This means that walls become floors and ceilings while some cooridoors become drop shafts (down is now sideways). If you had to manuever through the ship while it is thrusting this would change the spatial layout of the ship, potentially becoming very disorienting.

I think that if this were a problem, wouldn't ships simply be built to accomodate? By that, I mean, why build the ships as if gravity were "down" (as if it were a ship on a planet) and then suddenly shift so that everyone is pulled "sideways" whenever the ship accelerates?

Just build the ships decks already sideways. That way, when the ship is accelerating, the decks and doors seem normal, and when the ship is not accelerating and there is zero gravity, it doesn't matter which way it's built anyway. There's no reason at all to force the ship to "change" depending on whether it's standing still or moving.

The only time I can visualize it changing is if the ship fired it's engines or jets to move straight "up" or "down" or strafe "left" and "right."

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Original post by Taolung I think that if this were a problem, wouldn't ships simply be built to accomodate? By that, I mean, why build the ships as if gravity were "down" (as if it were a ship on a planet) and then suddenly shift so that everyone is pulled "sideways" whenever the ship accelerates? Just build the ships decks already sideways. That way, when the ship is accelerating, the decks and doors seem normal, and when the ship is not accelerating and there is zero gravity, it doesn't matter which way it's built anyway. There's no reason at all to force the ship to "change" depending on whether it's standing still or moving. The only time I can visualize it changing is if the ship fired it's engines or jets to move straight "up" or "down" or strafe "left" and "right."

Don't forget decceleration - it's all very well designing your ships around thrust in one direction, but you're also going to need to reverse that thrust at some point, and you don't really want your entire crew to suddenly fall onto the ceiling.

Of course, you could simply rotate your ship around so it's pointing the other direction before accelerating, so you're always accelerating along the same axis. This would be good for smallish ships, (it would also save you needing an extra bunch of engines on the front of the ship for decceleration) but for a very big unmanouverable ship this could be a bit of a pain in the arse. Another alternative would be to build the occupied areas of the ship as a series of rotating compartments, that can rotate automatically to align themselves with the axis of thrust. Of course, you'd probably still end up with some parts of the ship in inertial no-mans-land, but that would certainly fix the problem - at the cost of requiring extra infrastructure.

[Edited by - Sandman on September 13, 2004 1:07:54 PM]

A quick brainstorm:

* I'd say that rotating any ship in the opposite direction would be much more effective than adding reverse thrusters. You'd save a lot more mass that way. The only problem might be if the ship's got a rotating section as it will resist that change (think spinning top etc.).

* In the same way, you wouldn't need to stop the rotating section to thrust, only if you needed to change orientation.

* In any case, if a ship was built where the apparent direction of gravity changes for whatever reason, the insides of the ship would take that into account. For example, if the ship will mainly accelerate and decelerate, then floors and ceilings must be interchangable. Walls too, maybe. Some features might have to appear on both the floor and the ceiling (e.g. stoves in the galley, and what about toilets?) which might be another reason to limit that sort of thing as much as possible.

* If a ship were to change direction the change might be imperceptable near the centre of the craft (well, you'd turn, but air resistance in the ship might make you turn with it, making it less pronounced), but might manifest itself as a force several times that of Earth gravity further out.

* If you can create a force that can simulate gravity, you can also use that force to cushion against unwanted gravitational effects.

I wouldn't expect ships to have walls become floors, or anything like that during acceleration. If these are used at all during acceleration, then the ship would be built along that axis.
Another, more likely situation would be that the crew just don't move around much during acceleration/deceleration. Either they're at their assigned posts, or they're in one of the areas with artificial gravity. The routes between these areas probably wouldn't have actual "floors, walls and ceilings" anyway. They'd either be elevators or a kind of corridors with stairs or handholds on every "wall". In those areas, there just wouldn't be one single side that's made to be floor. And they wouldn't be used much during acceleration/deceleration. Maybe during crew shift change, or in emergencies/special events. Normally, people would stay in one place, or in the gravity areas.

During normal flight, I dont think gravity should have any effects. (other than limiting your max acceleration because there's a limit to how much gravity the crew can handle).

On a spaceship, I'd expect the crew to be prepared for these things. They'd make sure to be securely strapped in during acceleration/deceleration, so I don't think it would be a problem. (Maybe you could allow the player to increase acceleration beyond what your crew can safely handle, for use during emergencies. But under normal operation, the crew should be safe, with no ill effects, because that's basically their job. If they have to accelerate fast and for an extended period, then they'd have some couches to dampen the effects, or use some kind of exoskeletons for support or whatever. In short, they would never, under normal non-emergency operation, accelerate so much that it becomes harmful for them.

I think the bigger problem is what to do when the ship is just coasting to save fuel. Then having no gravity would probably be a likely option. To compensate for this, I'd expect them to have the crew quarters provide some kind of artificial gravity. When working, they might have to go into the gravity-less areas of the ship (engines, generator, cockpit, gun turrets or various other components), but again, they would implement measures to keep them safe, and they wouldn't be there all day. I'd say that's a given for any starfaring culture. They won't begin using spaceships on a large scale until they've figured out how to keep the crew in decent health.

So I think that during normal flight, it shouldn't be an issue at all. The crew is safe if the ship has the most basic systems in place. (Maybe you can get a cheap junk-pile that can't provide artifical gravity at all during coasting, not even in the crew quarters)

It could still influence the following though:
- Some engines might rely on very short bursts of high acceleration (like chemical rockets). This would force the crew to spend much more time coasting, and so could increase the chance accidents related to the lack of gravity. (Not sure if this is a good idea, considering I just said coasting shouldn't influence the crew. Maybe certain engines just have a special "burst" property, which lets them accelerate better, but also eats much more fuel, and, because it'll require more coasting time, will also create a chance that some no-gravity related accident/event happens. So it's not something gradual, but a binary property an engine either has or doesn't have. Because I dont think it should be a problem at all for normal engines.)

- During battle/boarding. As you said, bursts of acceleration/deceleration can be an effective weapon to fight boarding parties.

- If the ship's artificial gravity mechanisms have been damaged, the entire ship will have no gravity until it's fixed.

- If other parts of the ship has been damaged, it might be neccesary to shut down the artificial gravity mechanisms before it's possible for the crew to repair the damage.

- In an emergency, you might need a boost with some really extreme acceleration, which would influence the crew

Basically though, I think it should be kept as special states that only applies some times. During normal flight, it shouldn't be an issue at all, but when one of the above situations occur, you might enter the high- or low gravity state, with all the penalties and chances of accidents that follow.

I once read a "hardcore" sci-fi book where the story happened on a high gravity planet. The writer (scientist of some sort) told in the book, that he did not have any artificial gravity machinery, as it would have caused troubles that are usually ignored.

At least he mentioned that the difference of potential energy between the areas of normal gravity and artificial gravity would prevent a object to move from one environment to another.

I guess that it meant that the space warping nature of gravity would make impossible to have sudden changes in gravity. Think about water making walls on the sea. (Okay, this is not the best analogy but you get the point. I hope.)

The changes of gravity (even gradual, if on a short distance) would also stress a lot any structure, so a ship with any sort of arti-grav - regular grav -mix would be, well, if not impossible, then at least impractical.

But finally, yes, i would enjoy if a space game had some gravity-related content. And in a game it does not have to be so exact, as long as it follows its own rules, thus not breaking the suspension of disbelief.

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Original post by rrc2soft For what i read in your post, gravity will impose lots of limits for "low-level" (e.g. in the first hours of the game) players. When the crew is less experienced, they (and also any passenger) will suffer from almost any extreme decision (save fuel, acceleration for the deadline, long travels, sudden acceleration). Maybe this will be OK if you want to use gravity as an indicator of the evolution of your players, but you should balance what low-level players can do. I think... Gravity can be OK if you use it as an element of decision for your players - if (for example) I use more money in increasing the possible cargo of the ship, I'll be more vulnerable against moments of crisis when i have to make extreme maneuvers ("Captain, the pirates are very near, we must accelerate now!" ("Damn, now is when we will miss the gravity stabilizers...")).

I like the idea of keeping this constant more so than just an indicator of level. Toward that end, maybe I'll make the cost of getting rid of zero-G or high-G increasingly exhorbitant so that it delivers diminishing returns.

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About boarding and personal combat, depends on how you will design the actual combat.

Thinking 3rd person if you choose to board, otherwise it's abstract 'over the comms' reports. Not sure if I can squeeze in any really significant player micromanagment of the battle outside of the section you're in at this point. So you'd be 3rd person, fighting directly with your character, taking cover, setting priorities and objectives for your crew, then getting back up and pressing the attack.

I just remembered, that gravity also affects time. Tought, that it would be worth mentioning, too. Think about spaceship, where different parts have different speed of time. The differences are minimal in real life, but they are there.

Differences could possibly build up when traveling at relativistic speeds? Could cause some interesting situations:
"Sir, our time coherency protection went doooooooooowwwwnnnn..." :)

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Original post by Taolung I think that if this were a problem, wouldn't ships simply be built to accomodate? By that, I mean, why build the ships as if gravity were "down" (as if it were a ship on a planet) and then suddenly shift so that everyone is pulled "sideways" whenever the ship accelerates?

You may be right. However, logically, there are some cases where I can see a common "long and flat" design being more practical:

1) The vehicle is designed to spend extended periods in a gravity well, such as hopping between cities, belly-landing to carry cargo or otherwise operating for extended periods aerodynamically in atmosphere

2) Load bearing may be easier with a vessel that's aligned on a column above the source of acceleration as opposed to arrayed around it. Think about it like picking a pancake up with a ball point pen versus the structure of the ball point pen itself. If you want a bigger ship and you expand outward, it's going to put more force against a smaller surface area of the ship. Also, th more massive the vessel, the more a tail landing scheme will cause similar problems, not to mention creating a towering structure that is vulnerable to wind.

3) Tactical vulnerability: When a ship accelerates toward or away from an aggressor, having a thin and long structure would be preferable to the wide structure, especially in terms of area of effect weapons.