PRAISE TO ARMOK!
This is exactly what I needed! I'm trying my hand at modding for the first time, and could really use some help. Making the creatures was easy enough, but the entity part is trickery.
I'll be hanging around to help anybody I can, if i can, and ask some questions of my own from here on in.
For starters, what determines what sort of structures a civilization will build, and out of what material. So for example if I wanted to build a dark tower out of ice, is that possible?
While I'm almost 100% sure there's no way to actually change what a specific site type looks like or what the buildings are made from (though I'd love to be wrong!), the various site tokens determine where a civ lives while the construction tokens determine what other things they build.
This is for sites:
[DEFAULT_SITE_TYPE:<site token>]
[liKES_SITE:<site token>]
[TOLERATES_SITE:<site token>]
The civ will usually dwell in the DEFAULT_SITE_TYPE, but some events in world gen can force them to move to their LIKES_SITE or TOLERATES_SITE. The chance is higher for LIKES_SITE than it is for TOLERATES_SITE. Typically the DEFAULT_SITE_TYPE site token is also put as a LIKES_SITE and TOLERATES_SITE, and for the vanilla civs is the only LIKES_SITE. This might influence what new sites are built by the civ, but I'm not entirely sure.
Site tokens:
CITY - this is the standard town with shops and mead hall (used by humans in vanilla)
TREE_CITY - use this if you want them to just sorta hang around outdoors
CAVE - the civ will live near entrances to caves
CAVE_DETAILED - dwarf fortress sites
RUIN - run down version of another site that's been destroyed in world gen
DARK_FORTRESS - this is the big obsidian tower site
World constructions are other things the civ will build besides sites:
[WORLD_CONSTRUCTION:<construction token>]
Construction tokens: WALL, ROAD, TUNNEL, BRIDGE