Anyway, hi, name's Tiel. I first ran across Spring back in the summer of 2009, and while I've tried it throughout the years since then, it's only now I'm making a serious attempt at figuring this all out.
So, I've got a single unit ingame with teamcolors by following the plethora of tutorials available (doesn't fire and they actively try to bludgeon each other to death when moving in groups, but hey, progress). The game I'm making is science fiction and set in space. I already have all the models and textures for them (or soon will, it's something of a collaborative project by a community) so I'm pretty well set, save for these few questions.
1) Capturing things: It seems like this is a default function within Spring, but I haven't got anywhere on searching. Basically, would like to have buildings (planets, actually) neutral at game start that are able to be appropriated by sending a unit to garrison it.
The difficult part is that I'd like to have said unit remain 'inside' the building as a statistic, like Starcraft's bunkers except incapable of firing out, and that the enemy faction can send their own units to 'garrison' it, upon which the forces there fight, somehow, until one comes out the victor and either seizes or retains control of the building.
I guess one way the latter could be simplified is by just teleporting the units inside the building and just standby until either called out or an enemy unit is similarly garrisoned, whereon they'll actually fight. Can the Spring engine keep track of that kind of thing and swap control over to the invading force should they succeed? This is supposed to represent the two armies fighting on the planet's surface.
2) Space: The game's basic design could, in a nutshell, be described as "a poor man's Sins". I've already looked around and found that making the skybox that of space and using some form of 'void' tag on the map's definition (allowing transparency) would suffice to create this effect, though there are some complications.
The first would be that the idea here is to have...well, easier to have a picture.

The black is transparency; unimportant and easily doable. The white circles are gravity wells, which have some opacity within their radii to better represent where they are. These need to be high fidelity and on the map's texture itself, or as part of the planets' models, which are the green balls in the wells.
Several issues are presented by that alone. I've read that Spring doesn't like any sort of alpha channel trickery that isn't a box. That would be negated somewhat by having the wells be part of the planet's model, but understand that units will be moving within these wells. Perhaps put the texture plane for that beneath the actual ground collision they'll be moving on (which shouldn't be a problem since the ground is transparent)?
Lastly, the gray lines represent the mass accelerators tying everything together. A mass accelerator would be a teleporter structure spanning from one gravity well to another, a high visible beam of light crossing the distance between two neutral emitters. I present to you another poorly drawn Paint image.

The idea is you move your units to 'garrison' accelerator A and they then pop up around accelerator B. The light is just there to serve as an indicator to players where the routes are, as they'd be destroyable to potentially isolate a system. They'd be rebuildable, of course, but movement through space from one planet to another in order to establish such a construct would be exponentially slower than utilizing an accelerator.
And that's another point of worry for me. AI. Will they use these teleporters or troll around in dark space? Is there any way to induce them to want to construct an accelerator link? Will they deliberately destroy them on sight for some inexplicable reason? I have no experience with artificial intelligence, so I'm at a loss here.
3) Statistics: Is Spring capable of doing stuff, like, I dunno, having something of an overall 'morale' percentage that's affected by units dying, planets lost, and affects how slow construction is and/or how expensive they are in the first place?
Would it be possible to have something of an exp system where the player ranks up and gains new stuff through the same method, should it exist?
Is it also feasible to, rather than have an infinite pool of resources, have a 'pool', a maximum that the player can reach that can be increased by other factors, sorta like the old C&C games?
4) Missions: I'd like to have a system in which the game sporadically offers assignments to a player like 'patrol x gravity well' and records their success or failure in it and offers rewards appropriately. The exp system, should it be feasible, would heavily factor in it, I'd imagine. Just a way to keep people busy and entertained.
5) GUI: I mean no offense, but Spring's default GUI is pretty clunky. How does one go about changing this and skinning it afterwards?
6) Pathfinding: Oh lawdie. I just wanted to get this out of the way, because after moving my units around in the field and laughing a bit at their stupidity I couldn't find anything to help the fact that a formation of units act like bumpercars.
I read "Forbie's guide to making the pathfinder love you(?)" but it appears all the changes he made are default now, save for heatmapping which doesn't seem to help anything. How do you accomplish stuff like this and this, which are demos for .88 and .86, respectively? Were the devs just cockteasing a feature that was never added, or am I just doing something horrendously wrong?
I think that's about it. Thank you for any help and I apologize if I come off as demanding. My project's pretty much hit a standstill until I can get assistance with this stuff.