1. Minefields in space, especially in deep space, are a completely ridiculous notion. If you wanted to place even a single line of mines across 1 map tile in GCII, then you'd need 3X10^13 mines if they were spaced 1 km apart. If we want to fill a cube 1 parsec on a side (basically, the tile of GCII extended to the third dimension with height equal to the base dimensions), then you'd need about 3X10^40 mines, again with a 1 km spacing between mines. This is inadequate to give a reasonable likelihood of hitting anything smaller than the largest two classes of warship in GCII, and would require an excessive commitment of resources for something that can be bypassed merely by flying around it, nor is there any reason why a ship which is capable of destroying craft similar in size to itself should be incapable of destroying a mine which is in some sense stationary unless said mine cannot be detected with sufficient accuracy for targeting; however, we're talking about ships which can carry defenses which can shoot down high-speed missiles in a high-noise environment, while mines are likely to be larger (especially with the spacing given above, because if you have such a coarse net you want every hit to count) than the missiles, will not be moving, and the environment will be far less noisy, meaning that the sensors should have a much better chance of locking onto the target.

Orbital minefields are somewhat more practical, as they are in a position where you know that enemies are going to pass through or want to occupy for blockades, orbital bombardment, and invasion, and conveniently enough you have a whole planet nearby which can provide sensor jamming, deter minesweeping activity by means of more standard orbital defenses. On the other hand, the numbers required for such minefields are still enormous (though not to the same extent that the minefields described previously are enormous), and there's still the problem of if the enemy fleet has local space superiority you won't be able to replenish the minefield easily, meaning that if the enemy wants to spend enough time doing so, they can break the minefield. Additionally, such a minefield is reasonably likely to get in the way of your own activities, and would be a convenience for a blockading force - since most minefields are indiscriminate area denial tools, putting one up would just mean one less area of orbital space that the blockade fleet needs to keep watch over.

It's also completely unreasonable that I would be unable to clear a minefield if I decided to commit resources into doing so, unless I was unable to obtain sufficient superiority in the local region to prevent (or at least significantly hamper) minelaying activity  performed to restore cleared parts of the minefield.

2. I really dislike the whole "borders are walls that cannot be crossed without the express permission of the owner of the territory" thing. Borders are imaginary lines drawn on land, in the sea, or in space, and only sometimes correspond to actual physical barriers. It's only because most nations don't want to provoke international incidents or start wars that borders are normally respected, and nations which don't particularly fear their neighbors have been known to violate borders and ignore the resulting complaints, which doesn't always result in wars (at least technically), especially when there is a significant disparity in the military strength of the nations involved and the stronger party doesn't really want to go to war with the weaker.

Borders should only be inviolable in the sense that if you cross someone's borders without their permission, it hurts your diplomatic standing with them (and probably their allies), and gives you a bad reputation. If you ignore their demands for you to leave their space, it hurts your diplomatic standing even more; same goes for if you use your violation of their territory to move forces into position for surprise attacks. And if you accept the demand for your fleets to leave another nation's space, then they should be given flight orders to the nearest point on the border (preferably a shared border between you and the violated nation or the violated nation and international space) rather than this nonsense where things magically teleport out of the area when you say you'll withdraw. If you want to ensure the player gets their ships out if they say they'll withdraw, then force the ships into autopilot or teleport up to the maximum distance traversable by those ships in one turn and keep doing so until those ships have left the violated region of space, and deduct the movement points required to make that movement. Moreover, if I decide to ignore the 'get out of my space' order after all, or declare war before the ships have left that nation's space, then I should be able to override the movement orders if I want to do so (preferably with a significant diplomatic penalty for having ships in enemy territory at the time of a declaration of war - after all, that indicates premeditation). Laws like the one from the United Planets which require that no military vessels be present in the space of the target of the declaration of war should also be something you can choose to ignore if you so desire, but once again at a significant penalty to your relations with other nations.

I agree with some of this, however, I believe that borders should be auto generated, simular to GalCiv2 with some tweaks.  After it auto generates you should be able to diplomatically alter a border say star system Alpha is in neutral space as we both occupy planets in the system, my border between you will be at the most distant planet of the Gamma system to the Beta system.  Alpha is neutral space, (you could agree not to have military ships only trade/transport ships) or all ship kinds are able to move, Your border is at the most distant planet of the Omega System to the Delta system.  Borders are closed diplomatic treaty, meaning none of my ships or their ships will automatically fly into each others space.  You are able to manually cross the borders with potential diplomatic issues possibly leading to war!!.  Also giving the player a warning in case they didn't want to cross the border and it was accidental, however, once you accept that you indeed want to cross no more warning message given until diplomatic agreement is renegotiated.

Just my thoughts... 

Also, should you have no diplomatic agreement with said race, and you cross non-agreed upon borders you may hinder diplomatic negotiations with them by not discussing.  On the other hand you may gain diplomatic opinion in war like races by making the unknown race come to you first for diplomacy versus you making the first diplomatic contact.

Glad to help. Ready for more?

While it seems that time in a mine field could have an affect on the amount of damage, it seems to me that the number of mines you encounter would be a much bigger factor. Each mine would be capable of a certain amount of damage, but could not inflict that damage unless a ship came within range of that mine. One tactic, IIRC, in avoiding damage in mine fields in WWI and/or WWII was to go through the field very slowly, spotting each mine, and either diverting the mine away from the ship until the ship was past the mine or blowing the mine up at a distance (shooting the mine, throwing junk at the mine, what ever worked). Like you said in your item 3, this would slow down your progress, but perhaps it dosn't need to be slowed all the way to 1 tile per turn. Perhaps there could be techs for different levels of mine removal, or even techs for different methods of removing mines?

As to other poster's comments about whether "mines in space" is a valid or ridiculous idea, lets remember that this is a game. Does physics make it impossible? I don't know, and I don't think there is anyone that truthfully knows (i.e., has anyone really tested it out? and what yet undiscovered tech might make it possible?). Nor do I think math is a way of showing how impractical it is. In a game, such as a space game, where scale is such a factor, saying that you have to plant one mine every 1KM fails to take scale into perspective. The game can always envision "one mine unit" to mean as many mines as it takes to effectively mine a tile. This solves the scale issue and allows us to buy into the concept, and removes the need to apply math to the practicality of an idea.

I give up.  I'm going to come back to this forum in six months or something.

A huge waste of resources? Maybe, maybe not. But that doesn't make the idea a bad one.

And guess what. I like your idea as well.

Yeah, this was my point. I was trying to figure out where the guy who said invisible force field even got the notion.

If you want to deny trespass then you have to blow them up.  But you're losing sight of your other options when you do that.  How will trade work?  Closing your borders is a pretty aggressive stance to take.  Even the Drengin trade with others.

backs out of the room slowly...  

Well, there's a difference between allowing trade and allowing a military presence.

You'll notice that nowhere in that paragraph of mine which you quoted did I ever refer to how the borders should be generated. And for reference, I think that the GCII influence borders, which are the only auto-generated borders that I can think of in GCII, would be absolutely awful as territorial borders.

I did post an idea about borders earlier in the thread, namely:

which would seem to be the kind of thing that you're talking about.

This isn't solving the scale issue, it's ignoring it. Math and physics are always valid ways to show how impractical something is, as long as the computations involved are valid. This doesn't mean that games necessarily have to work in a practical manner, but there are some things which are much less reasonable than others. Interstellar minefields are one of those things. And for the record, a 1km spacing on the mines within the minefield? That's an extremely loose net when the majority of the targets that you're trying to catch have a maximum dimension which is much less than 1km.

Going beyond that, if we assume that each mine can be modeled as a sphere with a 1 meter diameter, and that the largest capital ships in GCII can be modeled as a 1kmX0.5kmX0.5km box which is 80% hollow, then that minefield that I described earlier uses enough resources to build roughly 2.5X10^33 capital ships of the largest class in GCII. Even if we model the ships as 100% solid, it's still enough for about 4.5X10^32 capital ships. That's for a minefield covering just one 1 parsec by 1 parsec by 1 parsec tile while spacing the mines at 1 km apart. You can increase the spacing all you want, but by the time the resources involved become reasonable, the minefield is so diffuse that it might as well not exist. Alternatively we can scale up the size of the capital ships - let's say our capital ships are cubes with the sidelength equal to 2km and are 100% solid; in that case the minefield described earlier contains sufficient material for 1.5X10^31 such capital ships.

Maybe we should go with numbers for one of the largest ships ever seen in a movie? Let's say the second Death Star. The official size of that thing is at least 900km, according to Wookieepedia. If we assume that that thing is 100% solid, then our minefield contains enough material for merely 4X10^22 900km diameter Death Stars. Let's go up in scale even further - how about Larry Niven's Ringworld? Based off of a quick Google search, the dimensions for that thing is that the ring has a circumference of about 600 million miles (multiply by 1.609 to get to kilometers), is 1 million miles wide, and has rim walls about 1000 miles tall. For simplicity's sake, I'm going to assume that this thing is solid, even though it is probably closer to 90% hollow, and that the ring is cylindrical rather than spherical in form (I don't know if it is or isn't, though cylindrical works out better if you're going to use platform rotation to maintain artificial gravity, which is how gravity on the Ringworld was described as functioning). This gives us that our minefield contains 'only' enough volume to construct 2.5X10^13 Ringworlds. Mind you, this is a structure with an inhabitable surface area equivalent to 3 million earth-like planets, and aside from the Dyson Sphere the largest artificial structure in science fiction that I can think of. I've also significantly overestimated the volume of the Ringworld, so you're likely to have enough material for far more Ringworlds than I described, though I doubt that the difference is more than an order of magnitude or so.

Since I brought up Dyson Spheres, let's do the math for one of those, assuming that the shell is 1000 miles thick and the thing has a diameter equal to the average orbital diameter of Earth. Based on those assumptions, our minefield only contains enough material for about 2.7X10^11 Dyson Spheres.

Let's go one beyond that, and assume that each mine masses only 1kg despite being a 1m diameter sphere. In that case, if we define a 'solar mass unit' to be the mass contained within the Sun and the eight officially recognized planets in our solar system, you would need 'merely' 61.1 billion solar mass units in order to make your minefield.

Are you starting to see just why it is that I object to the practicality of this thing yet? Now, maybe we can open the spacing between the mines up by several orders of magnitude - let's say that instead of a 1-km spacing we use a 1000km spacing (clearly, our 'mines' must now be weapons platforms rather than traditional mines, because the frontal area of even the largest ships in GCII is tiny relative to the area between mines for this hypothetical minefield). In that case, we can reduce the number of mines in the field to only 1.2X10^32 mines, which would 'only' require 61.1 of the solar mass units defined earlier, and 'only' contain enough volume for 268 Dyson Spheres or about 24,000 Ringworlds, using the previously listed assumptions. If we want to use 'only' 1 solar mass unit on our 1kg 1m diameter mines, then we'll be looking at a spacing of about 4,000km between each mine. Given that the complexity of each mine in our minefield is now approaching the complexity of a starship or a space station, maybe we should consider building some of those instead of building a minefield? If we up the spacing on the mines out to 1 million kilometers, then we'll only need about 3X10^22 of them, and we'll need "only" 3 Pluto-sized objects to provide the mass for it (again, assuming that each mine masses 1 kg). If you want to, you can carry out the math to get the equivalence in Death Stars, GCII capital ships, Ringworlds, Dyson Spheres, etc. I'll point out that even with this kind of spacing, you're still looking at lots of most of those (it's no longer a sufficient volume for a complete Ringworld or Dyson Sphere, but you could still build ~40,000 Death Stars or ~2X10^14 GCII capital ships with what you put into the minefield).

By the way, all of this is being sunk into something that 1. can't move and 2. is easily bypassed (even on the 2-dimensional grid; if we're looking at a 3-dimensional space then it becomes even easier to bypass). I'm fine with accepting certain things which are completely unrealistic at the present time, but I am not willing to accept minefields that, in order to have even a hope of becoming practical, must involve an amount of mass on the order of entire star systems, or worse billions of star systems. I realize that these arguments also apply to one extent or another to GCII's space stations (immobile, so you can bypass them, and so small relative to the scale of the tiles that it isn't really apparent why you have to fight them if you move into the tile), but at least those are something that I might reasonably want to engage, and also have some kind of magical ability to influence battles/economies/etc within a certain radius of the station (or mine things which magically make everything better for one faction).

While your response was a hilarious hammer blow, a small number of  mobile mines with basic sensors and basic hyperdrives could completely bypass the problem of resources. Boom, you need a few dozen mines to cover a Parsec, not... Trillions.

I was thinking about the minefields. I don't know if they r practical or not. I Think these ideas r insightful. I do think we need to take into account inflation, technology, and the mathematics of

     First r we talking about regular mines. Then we would have to have a high orbit otherwise they would burn up in the aptmosphere. Unless they were heat shielded enough. Then they would eventually hit the ground and explode. Someone is unemployed, or maybe in jail for this idea. I would figure that mines would have to have meneuvering jets and radar to pull this off. Radar for 2 reasons to find the ships, and to know if they r friendly or not. A low planet orbit would mean that u need less mines, but would require more fuel because of gravity restraints. While a higher planet orbit would require less fuel, but u would need more mines. Remember the higher the altitude the more time u have to stop the ships. Lets not forget about radar jamming ships. If this would require some kind of hub then this could be a target to go after.

     Second u have to take into account fuel the type of fuel would make a difference.

     Third is what kind of explosives, and how big r the mines. Size affects how much fuel u can carry. Which could be a factor on speed. Yes u should take speed into account. How much fuel u could carry could affect range. Both the fuel and explosives could affect how big of a mine u need to take dowm what kind of ship. Both the hulls, hitpoints, and logistics could be taken into account. The bigger the hull, and the more hit points would affect how much damage u would take. Remember if u r expecting a bunch of small or medium ships coming through your space it would not make sense for u to pack the explosive power for huge hulls. This could be taken into account if u r the first person to research a hull design, or get hitpoint techs.

     Fourth we need to take into account inflation, and materials needed to build them. I would agree that there would have to be a lot of mines, but if inflation has made these so cheap this could be affordable.

     Fifth how about a planetary defense like starwars instead. Why can't mines be lasers instead.

     Sixth assuming they r not lasers. U would need to remember that the ship has only a 2 degree that they could enter the planet this may shorten how many mines u would need.

     I figured it would be so obvious that the invisible force fields were a reference to how Civilization 4 worked out its borders. They made it that u could not enter a  enemies territory unless u have a right of passage agreement. I don't like this method of get out of my space. I preferred Civilization 3's method where u could tell someone that they were trespassing, and u had 5 choices on how to respond you could comply and leave the territory, u could say no, u could sign a right of passage agreement, u could ignore the request and not respond, or u could declare war. If the person didn't like the response you had the option to declare war. I think if I enter your territory, and u don't like it then u should make me stop not raise an invisible border I cannot cross. Another thing I didn't like about Civilization 4's method is that when I broke a right of passage agreement it took 20 turns before I could do anything.I'm guessing u never played Civilization 4.

     I think neutral ground should also work on people following the law. That u should also have the option to ignore this law. I'm not saying the Ai should not have repercussions. Maybe the players should vote to throw u off or not. There's always the diplomacy option. Trade embargo. If the computer wants to be but hurt if u snead attack then that's their perogitive. Even though I would vote against this I would like to call a vote on wether the Galactic council van raise an army to enforce these laws or not. Starbases and mines at least explains how these things r being inplemented. I would also like the armed freighters have to fight it out; even if they r the best ships on the game. Remember that the technology would not be so advanced that the council could not build it; because no one knows how to build these ships.

     This does not  nessarily change your argument, but the calculations don't make sense to me even if U apply volume and not area. The Dyson sphere Is a million kilometers in diameter; while,the earth and the mine field is only about 13,000 kilometers in diameter. This is not even 1 Dyson sphere per minefield, but we would have to account for area not volume. The mines would move making 1 kilometer a little close for a mine with a prewarning because of some interstellar communication that I don't understand. The area of a Dyson sphere would have to be a whole bigger than the diameter difference. If u can explain this further go agead. U might of added up all your planets to come up with this, but u also have a lot more resources. I like the weapons platform idea also. Even without all that stuff there is still alot of material required. I would like to point out that the Iconians would convert energy to matter; instead of manufacturing the mines.

     I so would like to vote at the Galactic council to define boundaries please. There may be an issue of plants getting trapped out of influence I guess these would have to be new civilizations.

i was going to say something similar although much simpler seeing you put all this into context blows my simple estimate of requiring every planet in your civilization focused on building this minefield away

the problem with this is the same as the problem i had in gc2 ultimately

if i declare war then I'm the bad guy while your the one trespassing and telling me to shove it or building your influence star bases next to my home-world

essentially if i tell you to leave and you refuse i should be able to arrest or destroy your ship without having to declare war

     Well to my opinion this should not make u the bad guy when I'm trespassing. As long as u r required to send out a ship and catch me then that will be fine. U still will only to see the territory that is lit up. I Think this is reasonable. The only thing I am arguing is this I don't think that u can block me from your territory without force. The obly time I thought it was wrong was in Civilization 4. Where u couldn't enter someelse's territory without a right of passage agreement, and if u declared war after u broke a right of passage agreement u couldn't enter the territory for 20 turns. I think u should give the players as mech dialogue as possible. U want to arrest me that's fine as long as u can catch me.

     O yeah that influence starbase thing. Please give me the chance to blow up other peoples starbases my own territory.

I realize you never mentioned borders, and I didn't say you mentioned it, I said I agreed with some of the things said, with a "however" in there where I think they should still auto generate borders...  I did not say specifically how, but I did say there should be tweaks to how it generates the borders in comparison to GalCiv2,

With this I said that you should be able then to negotiate the borders how you choose fit, if you choose to disregard them well that's up to you... 

As far as protecting them if you did place a mine field as mentioned with in this topic then you would most likely have anti mine technology which would allow one to send hundreds of probes or something into the mine field to trick them to destroying them versus you, therefore neutralizing this problem.

Personally I think this is really a matter of point of view. Some AIs, particularly allies, would have to be taught to recognize this as potentially a defensive action and some AIs, particularly belligerent ones, would have to see you as being a bad guy. But then, that is already how they see you, so how has their point of view really changed?