modifying unity is out, the license doesn't include source code and more than likely the problem isn't unity itself but the build process.
I wasn't aware they didn't have the source code. That does make it more difficult...
getting the game assets to use a little less memory might be possible, but that limit is still there and you will eventually exhaust it with mods anyway.
Nothing I see in the game appears to earn the huge amount of memory being taken. I'm not a programmer, but there's gotta be something they can do to free up at least 300-500MB of system RAM, even if it's an load-on-demand system.
a viable 64bit windows build is what you need as far as your memory issues, it will come, it's just obviously not top of the priority list.
Since they haven't yet managed to turn this thing into a game, but the modding community has, I'd say it should be #1 priority.
if you have a spare HD you can band-aid the issue by loading up ubuntu on it, booting to that, and running the 64bit linux version. it's a noticeable difference.
I have spare hard drives. Even a spare SSD. What I don't have is a spare computer that I can load it upon. My gaming PC hosts two friends/family Minecraft servers 24/7, so I can't be dual-booting.
Any word on how well KSP would run in an Ubuntu VM?...
I think KSP was always meant to be a light hearted sim, so actual gameplay was probably always pretty low on the list.
No, it's been pretty high on the list, as evidenced by their efforts in the tech tree, missions, and RPG elements. While it's been a pretty high priority, I think they've completely missed the mark...thus my assertion that they should focus on what they do well; make the sandbox excellent. Unfortunately, the 2GB limit is a HUGE handicap to this and, IMO, is what they should throw their efforts toward.
you can look at this one of two ways: 1: squad is dropping the ball on gameplay or 2: ever since the release of WoW's UI mod api, they've been setting the precedence of letting the community develop what THEY like and then adapting the really popular stuff into the main game.
Well, I listed a third way above, but regarding point #2, the 2GB limit hamstrings any such effort. Leaving me to assert that #1 is the reality.
Source: i work on build automation at a game studio that uses unity.
Given your field, do you have any idea why a bunch of simple 3D shapes, an environment mostly devoid of features, and quite-less-than-4k textures manage to eat so much memory? I mean, I ran GTA4 in 32-bit windows and it was far more complex than what I see in KSP. What is it about KSP and its mods which combine to reach the 2GB ceiling so swiftly?