I'm trying to find some sort of system for the construction of civilization, but am coming up with things that strictly assume civilization exists. When there's not a guild of masons to throw my gold at and get walls, what kind of rules are around for the gathering of materials and then putting those materials together in such a fashion as to generate huts, forges, and the like?
OD&D (v3, pg.22) and AD&D (pg. 29) both include tables outlining costs of expert hirelings. You might decide that hiring an engineer-architect and a blacksmith might be required to build the forge, etc., then add laborers and extra costs around gathering and preparing the lumber etc. My assumption being that hiring the specialist would amount to hiring a foreman who would handle the details and present the player with the bill.
If there are no experts, perhaps back up with some questions about how well the PCs would be able to design, plan, and execute - for instance - a forge. There are dependencies for a lot of technologies you might have to take into account. Would your character even know how to build a proper wall? Know not to build with green wood? How to build something that can generate and withstand the heat needed to melt iron? If there is no civilization to around are you already supplied with adequate tools including shovels, axes, grinding stone, picks?
A lot of things end up requiring surrounding infrastructure. Example: you want to make a 200-page spellbook. Forget magic inks and rituals: first you need the skins of 14-15 animals (goats, sheep, or calves). And even that assumes you have an experienced tanner who knows how to prepare the skin to make leather and parchment. Even if you can find a local who will sell you that many of their flock (which they rely upon for income/food/warmth, etc.) it will still take months to prepare the skins.
In short, depending on the goal, I would make it very difficult for players to build or reconstruct a civilization on their own - UNLESS (of course) it is more fun or expedient for the game to make it more simple.
Happy to kick more ideas around if you have something specific in mind.
Some things are adventuring hook type stuff: find an anvil, recover the spellbook, unrustle the sheep. But things like "Construct the shelter" aren't really adventurable, as carrying a house home from a dungeon is mildly difficult.
The context is I'm trying to set up a campaign where civilization was undone, and the PC's start re-establishing a livable place for them in the ruins of a large trade city. Rescuing of skilled npcs, re-establishing resource points, clearing the city, and finding new people kind of stuff. Behind the scene, atm I'm probably going to convert resources gathered into GP values (100gp of wood, 25gp of iron, et cetera), and then just assign a time to build based on some value. Early on one can only do simple work, but once you get a forge/sawmill set up, you can do more things, attract more people, whatnot.
A couple of things might be useful, and it sounds like you are already thinking about them. I would think in terms of dependencies, so once you assemble the things necessary for a blacksmith's shop, it takes 2 months to build. That list might be a bunch of mundane things like lumber and iron, but could also include finding an anvil, finding a blacksmith, searching out the old coal bin (now infested with stirges). You need a blacksmith to make the parts needed far a sawmill: but for a real mill you need a river site, waterwheel, stand of harvest-able trees (maybe a forester or ranger), etc. To get water, first you have to repair the old aqueduct (after you have found a supply of lead) and journey to the source to see why no water is flowing…
If I were doing this I would be tempted to make up a list of macguffins vital items and sprinkle them in the ruins. Including things like grinding wheels for a mill, anvils, coal storage, rumors pointing at where people moved their trade and families. Think about what the players will decide they need and make them adventuring sites: coal mine, forest (looking for stands of trees), exploring up and down rivers for building sites, stone quarry. Putting all that stuff around and you will have a nice little sandbox for people to explore.
Is this the sort of thing you are working on?
Yes, working on a sandbox based around the remains of a large city. The initial idea was to have the players come in very soon after a society destroying disaster, but I might move that to some time afterwards, as I blocked on building a city with barriers that aren't social/military. It would make explaining how things got built easier ("Go forth brave adventurers and clear the forest of Ye Olde Magics and then we can get the ingredients necessary for our local alchemist to brew potions of Remove Troll!"), and provides intercity intrigue earlier (The party doesn't have to discover the other factions in the city, they've already been discovered); however it removes a certain amount of emergent gameplay stuff built on by the players ("We didn't bother with x thing because we didn't have a need for y, but now we really need some z to deal with these wizards!"), and would inhibit exploring "under the rubble" of the city a bit (either the place is clear and there is nothing really under the rubble, or the new parts of civilization are built on top of it, creating very drastic consequences above ground for material shifting below ground, potentially ruining long-term work of the players.")
That was the general idea with the macguffins, yes.
Thanks for the help/input!
One unnatural disaster that would fit with the D&D theme: a whole city or even kingdom where the entire populace fell asleep at once, and died of starvation over the course of weeks. The smell and fodder would attract all manner of beasts and ruin would quickly overtake the city and villages. Neighboring kingdoms would at first fear what happened and stay away, then over time gradually come to wondering how they could annex part of the kingdom. Brave adventurers would gather, some hoping to loot, others to restore order, all hoping to take advantage of the vacuum of authority before some empress mustered an army…
Such a scenario could add a ticking clock, if you like.
Spoilers: the planned disaster is that civilization attempted to put too much order onto the world, and the primal forces bent back, snapping the rules for a moment; mortar crumbles, nails come lose, fences break, monsters suddenly have a large increase in numbers. This would close off city streets and things from carts and whatnot, but PC's can climb things.