Just to clarify this a little for you, inside the folder you installed cataclysm, look for the following folder ‘data’, inside it has ‘json’ inside it has ‘mapgen’.
In that folder is a series of plain-text JSON files (meaning you should be able to open them in a text editor, hopefully you have one that doesn’t ignore the new lines) Each of those files represents the recipe for a building. The part you are probably most interested in is:
[tt]
“mapgen”: [ {
“method”: “json”,
“weight”: 10000000,
“object”: {
“rows”: [
“",
"–O--,,,",
"|lcx|,,,",
"| c#O,,,",
"| ##|,,,",
"|r L,,,”,
"|r |,,,",
"|w ^|,,,",
"|-M----MMMMMM–MMMMMMM–",
"|w w w|",
"| |",
"|ctc |",
"|ctc | |",
"|ctc | |",
"| | |",
"|-±-| |",
"|F @@| |",
"|t |",
"|c @@| |",
"| |",
"|+| | |",
"|T|GS| l l l l l l |",
"|----------------------|",
"…"
],
“terrain”: {
".": “t_grass”,
"": “t_pavement”,
",": “t_pavement_y”,
" “: “t_floor”,
”-": “t_wall_h”,
"|": “t_wall_v”,
“O”: “t_window”,
“L”: “t_door_locked”,
"+": “t_door_c”,
“M”: “t_door_metal_locked”,
“w”: “t_gates_mech_control”,
“x”: “t_console_broken”,
“c”: “t_floor”,
"#": “t_floor”,
“r”: “t_floor”,
"^": “t_floor”,
“t”: “t_floor”,
“F”: “t_floor”,
"@": “t_floor”,
":": “t_floor”,
“T”: “t_floor”,
“l”: “t_floor”,
“S”: “t_floor”,
“G”: “t_floor”
},
“furniture”: {
".": “f_null”,
"": “f_null”,
",": “f_null”,
" “: “f_null”,
”-": “f_null”,
"|": “f_null”,
“O”: “f_null”,
“L”: “f_null”,
"+": “f_null”,
“M”: “f_null”,
“w”: “f_null”,
“x”: “f_null”,
“c”: “f_chair”,
"#": “f_counter”,
“r”: “f_rack”,
"^": “f_indoor_plant”,
“t”: “f_table”,
“F”: “f_fridge”,
"@": “f_bed”,
":": “f_dresser”,
“T”: “f_toilet”,
“l”: “f_locker”,
“S”: “f_sink”,
“G”: “f_oven”
},
“place_specials”: [
{ “type”: “toilet”, “x”: 1, “y”: 21 }
],
[/tt]
‘rows’ there has the full layout, but the keys for understanding what each letter means is in the ‘terrain’ entry and the ‘furniture’ entry
If you are willing to make yourself a layout for a new building, someone will probably happily help you add in the other stuff (about what items can spawn in that location and where and what enemies).
EDIT: ALSO, important to know, most buildings (that only take up one tile on the overmap) are 24 by 24, exceptions (i.e. multitile buildings) like hospitals, apartment blocks etc are i believe dynamically generated, but support for them is on the way http://smf.cataclysmdda.com/index.php?topic=6292.0, just remember they need to be composed of a series of regular 24 by 24 blocks ( so 48 by 48 is acceptible, as is 72 by 24… but 75 by 75 for instance is NOT)