Before it was released, SimCity Creative Director Ocean Quigley (who has since left Maxis to form an independent studio) said that SimCity's GlassBox engine was "built to be moddable." That may be true, but SimCity the game is a curated always-online ecosystem, not a fertile, offline ground for experiments which would otherwise interfere with the official multiplayer experience. The two seem at odds with each other, but yesterday, Maxis wrote that it encourages us to "create, redistribute, and consume Mods for SimCity." How does that work?

"...As long as you respect all of the rules and guidelines set in this policy." SimCity's always-online nature demands that mods are regulated against abuse, so Maxis has set a list of restrictions for potential mod-makers. You can read the official rules in the blog post , but I've interpreted them below:

1. Don't mess with "the simulation for multiplayer games and multiplayer features" and don't "jeopardize the integrity of the gameplay." This is confusing—how does one mod the single-player simulation without potentially affecting multiplayer games? This rule prevents more than it lets on.

2. Keep it ESRB E10+ and PEGI 7, don't use copyrighted material, don't abuse anyone, don't do anything illegal, don't mess with the executable files.

3. The SimCity EULA and EA's Terms of Service supersede these rules. This is a catch-all for loopholes they may have missed.

4. If Maxis doesn't like what you're up to, it can revoke these permissions and is free to "take disciplinary action against players who harm the experience of others." Presumably that's an account restriction or ban, not a time-out in the corner.

5. You can't sell mods, and EA doesn't owe you any money for making them. It also doesn't need your permission to distribute your mod or do anything else with it. This is lawsuit-avoidance stuff—you don't get to claim EA stole and profited off your derivative work because Maxis promoted or distributed it.

So, if you keep it kid-friendly, keep it non-infringing, and don't do anything that might affect the multiplayer experience in any way, go for it. Some already have been—Maxis points to Simtropolis , where mods have been posted which do everything from replace the train models to change the color of garbage trucks.

I don't mean to disparage those modders' work—visual changes are great—but they could be doing so much more if they were allowed to. There is some good news on that front—or, at least, a reminder that good news is still being examined. In a forum post today, Maxis reiterated that it is still "exploring an Offline Single Player mode" to give players "more room to experiment without sacrificing the integrity and experience" of the multiplayer.

That's what SimCity needs to truly support modding. Until players can get into the engine's guts and make something new—and aren't told not to or made to fear repercussions for affecting someone else's multiplayer game—it's only nominally "moddable." I appreciate that Maxis is encouraging modders, and that these rules are a stopgap, but I'd also love to stop hearing about explorations into Official Offline Mode Land, and start hearing about how we can found a settlement there.