File Format

BIC file format for Civ3 version 1.16f
{start file}
bytes	type		value
-------------------------------------------------------
TOP "BIC file indicator"
  4	char		"BIC "

TOP VER# SECTION (BIC Header)
  4 	char		"VER#"
  4	long		number of headers (1)

  For each header:
    4	long		length of header (720)
    4	long		0
    4	long		0
    4	long		BIC major version number (2)
    4	long		BIC minor version number (10)
    640	string		description 1
    64	string		title

TOP BLDG SECTION (Improvements and Wonders) 2
  4	char		"BLDG"
  4	long		number of building types

  For each building type:
    4	long		length of building data (252)
    64	string		description 3
    32	string		improvement or wonder name
    32	string		civilopedia entry
    4   long		doubles happiness of 4
    4   long		gain in every city
    4   long		gain in every city on continent
    4   long		required improvement/wonder
    4   long		cost
    4   long		culture
    4   long		bombardment defense
    4   long		naval bombardment defense
    4   long		defense bonus
    4   long		naval defense bonus
    4   long		maintenance cost
    4   long		happy faces (all cities)
    4   long		happy faces
    4   long		unhappy faces (all cities)
    4   long		unhappy faces
    4   long		number of required buildings
    4   long		air power
    4   long		naval power
    4   long		pollution
    4   long		production
    4   long		required government
    4   long		spaceship part
    4   long		required advance
    4   long		rendered obsolete by
    4   long		required resource #1
    4   long		required resource #2
    4	long		improvements (binary) 5:
								00000000
			center of empire			.......1
			veteran	ground units			......1.
			+50% research output			.....1..
			+50% luxury output			....1...
			+50% tax output				...1....
			removes pop. pollution			..1.....
			reduces bldg. pollution			.1......
			resistant to bribery			1.......

			reduces	corruption			.......1
			doubles	city growth rate		......1.
			increases luxury trade			.....1..
			allows city size level 2		....1...
			allows city size level 3		...1....
			replaces other buildings		..1.....
			must be	near water			.1......
			must be	near a river			1.......

			can explode or meltdown			.......1
			veteran	sea units			......1.
			veteran	air units			.....1..
			capitalization				....1...
			allows water trade			...1....
			allows air trade			..1.....
			reduces	war weariness			.1......
			increases shields in water		1.......

			increases food in water			.......1
    4	long		other characteristics (binary):
								00000000
                        coastal	installation			.......1
                        military installation			......1.
                        wonder					.....1..
                        small wonder				....1...
                        continental mood effects		...1....
                        research installation			..1.....
                        trade installation			.1......
                        exploration installation		1.......

			place of worship			.......1
			construction installation		......1.
    4	long		small wonders (binary):
								00000000
			increases chance of leader appearance	.......1
			build armies without leader		......1.
			build larger armies			.....1..
			treasury earns 5%			....1...
			build spaceship parts			...1....
			reduces corruption			..1.....
			decreases success of missile attacks	.1......
			allows spy missions			1.......

			allows healing in enemy territory	.......1
			required goods must be in city radius	......1.
			requires victorious army		.....1..
    4	long		wonders (binary):
								00000000
			safe sea travel				.......1
			gain any advances owned by 2 civs	......1.
			double combat strength vs. barbarians	.....1..
			+1 ship movement			....1...
			doubles research output			...1....
			+1 trade in each trade-producing tile	..1.....
			halves unit upgrade cost		.1......
			pays maintenance for trade insts.	1.......

			allows all civs to build nuclears	.......1
			city growth causes +2 citizens		......1.
			+2 free advances			.....1..
			reduces war weariness in all cities	....1...
			doubles city defenses			...1....
			allows diplomatic victory		..1.....
    4	long		number of armies required

TOP CTZN SECTION (Citizens)
  4	char		"CTZN"
  4	long		number of citizen types

  For each citizen type:
    4	long		length of citizen data (116)
    4	long		default citizen
    32	string		citizens (singular) name
    32	string		civilopedia entry
    32	string		plural name
    4	long		prerequisite
    4	long		luxuries
    4	long		research
    4	long		taxes

TOP CULT SECTION (Culture)
  4	char		"CULT"
  4	long		??? (33)
  4	long		??? (5)
  4	long		number of culture opinions

  For each culture opinion:
    4	long		length of culture data (88)
    64	string		culture opinion name
    4	long		chance of successful propaganda
    4	long		culture ratio percentage (3:1 = 300, 3:4 = 75)
    4	long		culture ratio denominator (e.g. the 1 in 3:1)
    4	long		culture ratio numerator (e.g. the 3 in 3:1)
    4	long		initial resistance chance
    4	long		continued resistance chance

TOP DIFF SECTION (Difficulty Levels)
  4	char		"DIFF"
  4	long		number of difficulty levels

  For each difficulty level:
    4	long		length of difficulty data (108)
    64	string		difficulty level name
    4	long		number of citizens born content
    4	long		max. government transition time
    4	long		number of defensive land units AI starts with
    4	long		number of offensive land units AI starts with
    4	long		extra start unit #1
    4	long		extra start unit #2
    4	long		additional free support
    4	long		bonus for each city
    4	long		attack bonus against barbarians
    4	long		cost factor
    4	long		percentage of optimal cities

TOP ERAS SECTION (Eras)
  4	char		"ERAS"
  4	long		number of eras

  For each era:
    4	long		length of era data (260)
    64	string		era name
    32	string		civilopedia entry
    32	string		researcher #1
    32	string		researcher #2
    32	string		researcher #3
    32	string		researcher #4
    32	string		researcher #5
    4	long		number of used researcher names

TOP ESPN SECTION (Diplomats and Spies)
  4	char		"ESPN"
  4	long		number of espionage missions

  For each mission:
    4	long		length of mission data (232)
    128 string		description
    64	string		diplomat/spy mission name
    32	string		civilopedia entry
    4	long		mission performed by (binary):
					00000000
			diplomat	.......1
			spy		......1.
    4	long		base cost

TOP EXPR SECTION (Combat Experience)
  4	char		"EXPR"
  4	long		number of experience levels

  For each experience level:
    4	long		length of experience level data (26)
    32	string		experience level name
    4	long		base hit points

TOP GOOD SECTION (Natural Resources)
  4	char		"GOOD"
  4	long		number of natural resources

  For each resource:
    4	long		length of resource data (88)
    24	string		natural resource name
    32	string		civilopedia entry
    4	long		type
    4	long		appearance ratio
    4	long		disappearance probability
    4	long		icon
    4	long		prerequisite
    4	long		food bonus
    4	long		shields bonus
    4	long		commerce bonus

TOP GOVT SECTION (Governments)
  4	char		"GOVT"
  4	long		number of government types

  For each government type:
    4	long		length of government data
    4	long		default type
    4	long		transition type
    4	long		requires maintenance
    4	long		??? (0 for Rebublic/Democracy, 1 for rest)
    4	long		standard tile penalty
    4	long		standard trade bonus
    64	string		government name
    32	string		civilopedia entry
    32	string		male ruler title #1
    32	string		female ruler title #1
    32	string		male ruler title #2
    32	string		female ruler title #2
    32	string		male ruler title #3
    32	string		female ruler title #3
    32	string		male ruler title #4
    32	string		female ruler title #4
    4	long		corruption and waste
    4	long		immune to
    4	long		diplomats are
    4	long		spies are
    4	long		number of governments

    For each government type:
    (performance of above goverment type versus each of the others)
      4	long		can bribe this government type? (0 = no, 1 = yes)
      4	long		bribery modifier vs.
      4	long		resistance modifier vs.

    4	long		hurrying
    4	long		assimilation chance
    4	long		draft limit
    4	long		military police	limit
    4	long		# ruler title pairs used (max is 4)
    4	long		prerequisite technology index #
    4	long		science rate cap (10 = 100% of gold can go to science)
    4	long		worker rate
    4	long		??? (-1 for Despotism/Communism, 0 for Anarchy/Monarchy, 
			1 for Republic/Democracy)
    4	long		??? (1 for Republic/Democracy, 0 for the rest)
    4	long		free units
    4	long		all units free (-1 = yes, 0 = no)
    4	long		free units per town
    4	long		free units per city
    4	long		free units per metropolis
    4	long		cost/unit
    4	long		war weariness

TOP RULE SECTION (General Settings)
  4	char		"RULE"
  4	long		"number of rules" (1)

  For each rule:
    4	long		length of rule data
    32	long		city size level 1 name
    32	long		city size level 2 name
    32	long		city size level 3 name
    4	long		number of spaceship parts

    For each spaceship part:
      4	long		number needed of this part

    4	long		advanced barbarian 
    4	long		basic barbarian
    4	long		barbarian sea unit
    4	long		cities needed to support an army
    4	long		chance of rioting
    4	long		turn penalty for each drafted citizen
    4	long		shield cost per gold
    4	long		fortress defensive bonus
    4	long		citizens affected by each happy face
    4	long		??? (50)
    4	long		??? (2)
    4	long		forest value in shields
    4	long		shield value in gold
    4	long		citizen value in shields
    4	long		default difficulty level
    4	long		battle-created unit
    4	long		build-army unit
    4	long		building defensive bonus
    4	long		citizen defensive bonus
    4	long		default money resource
    4	long		chance to intercept enemy air missions
    4	long		chance to intercept enemy stealth missions
    4	long		starting treasury
    4	long		??? (16)
    4	long		food consumption/citizen
    4	long		river defensive bonus
    4	long		turn penalty for each hurry sacrifice
    4	long		scout
    4	long		slave
    4	long		movement rate along roads
    4	long		start unit 1
    4	long		start unit 2
    4	long		minimum population for we love the king
    4	long		town defense bonus
    4	long		city defense bonus
    4	long		metropolis defense bonus
    4	long		maximum level 1 city size
    4	long		maximum level 2 city size
    4	long		??? (1000)
    4	long		fortifications defensive bonus
    4	long		number of culture levels

    For each culture level
      64 string		culture level name

    4	long		border expansion multiplier
    4	long		border factor
    4	long		future tech cost
    4	long		golden age duration
    4	long		maximum research time
    4	long		minimum research time

TOP PRTO SECTION (Units)
  4	char		"PRTO"
  4	long		number of units

  For each unit:
    4	long		length of unit data (156)
    4	long		zone of control
    32	long		unit name
    32	long		civilopedia entry
    4	long		bombard strength
    4   long		bombard range
    4   long		capacity
    4   long		shield cost
    4   long		defense
    4   long		icon index
    4   long		attack
    4   long		operational range
    4   long		population cost
    4   long		rate of fire
    4   long		movement
    4   long		required
    4   long		upgrade to
    4   long		required resource #1
    4   long		required resource #2
    4   long		required resource #3
    4   long		unit abilities (binary):
							00000000
			wheeled				.......1
			foot soldier			......1.
			blitz				.....1..
			cruise missile			....1...
			all terrain as roads		...1....
			radar				..1.....
			amphibious unit			.1......
			submarine			1.......

			aircraft carrier		.......1
			draft				......1.
			immobile			.....1..
			sink in sea			....1...
			sink in	ocean			...1....
			mounted				..1.....
			carry foot units only		.1......
			starts golden age		1.......

			nuclear	weapon			.......1
			hidden nationality		......1.
			army				.....1..
			leader				....1...
			ICBM				...1....
			stealth				..1.....
			can see	submarines		.1......
			tactical missile		1.......

			can carry tactical missiles	.......1
			ranged attack animations	......1.
			turn to	attack			.....1..
    4	long		AI-strategy (binary):
							00000000
			offense				.......1
			defense				......1.
			artillery			.....1..
			explore				....1...
			army				...1....
			cruise missile			..1.....
			air bombard			.1......
			air defense			1.......

			naval power			.......1
			air transport			......1.
			naval transport			.....1..
			naval carrier			....1...
			terraform			...1....
			settle				..1.....
			leader				.1......
			tactical nuke			1.......

			ICBM				.......1
			naval missile transport		......1.
    4   long		available to (binary)
    4   long		standard orders/special actions
							00000000
			skip turn			.......1
			wait				......1.
			fortify				.....1..
			disband				....1...
			go to				...1....
			load				..1.....
			unload				.1......
			airlift				1.......

			pillage				.......1
			bombard				......1.
			airdrop				.....1..
			build army			....1...
			finish improvement		...1....
			upgrade				..1.....
			build colony			.1......
			build city			1.......

			build road			.......1
			build railroad			......1.
			build fort			.....1..
			build mine			....1...
			irrigate			...1....
			clear forest			..1.....
			clear jungle			.1......
			plant forest			1.......

			clear pollution			.......1
			automate			......1.
			join city			.....1..
    4	long		air missions (binary):
							00000000
			bombing				.......1
			recon				......1.
			interception			.....1..
			re-base				....1...
			precision bombing		...1....
    4   long		class 0=land, 1=sea, 2=air

TOP RACE SECTION (Civilizations)
  4	char		"RACE"
  4	long		number of civilizations

  For each civilization:
    4	long		length of civilization data
    4	long		number of city names

    For each cityname:
      24 string		city name

    4	long		number of leaders

    For each great leader:
      32 string		great leader name

    32	string		leader name
    24	string		leader title
    32	string		civilopedia entry
    40	string		adjective
    40	string		civilization name
    40	string		noun

    For each era:
      260 string	forward filename

    For each era:
      260 string	reverse filename

    4	long		culture group
    4	long		leader gender
    4	long		civilization gender
    4	long		aggression level (-2 to 2)
    4	long		unique civilization counter
    4	long		shunned government
    4	long		favorite government
    4	long		default color
    4	long		unique color
    4	long		free tech #1 index
    4	long		free tech #2 index
    4	long		free tech #3 index
    4	long		free tech #4 index
    4	long		bonuses (binary):
					00000000
			militaristic	.......1
			commercial	......1.
			expansionist	.....1..
			scientific	....1...
			religious	...1....
			industrious	..1.....
    4	long		governor settings (binary):
						00000000
			manage citizens		.......1
			emphasize food		......1.
			emphasize shields	.....1..
			emphasize trade		....1...
			manage production	...1....
			no wonders		..1.....
			no small wonders	.1......
    4	long		build never (binary):
						00000000
			off. land units		.......1
			def. land units		......1.
			artillery land units	.....1..
			settlers		....1...
			workers			...1....
			naval units		..1.....
			air units		.1......
			growth			1.......

			production		.......1
			happiness		......1.
			science			.....1..
			wealth			....1...
			trade			...1....
			explore			..1.....
			culture			.1......
    4	long		build often (binary, same as above)
    4	long		plurality

TOP TECH SECTION (Civilization Advances)
  4	char		"TECH"
  4	long		number of advances

  For each advance:
    4	long		length of advance data (104)
    32	string		advance name
    32	string		civilopedia entry
    4	long		cost
    4	long		era
    4	long		advance icon
    4	long		x
    4	long		y
    4	long		prerequisite #1
    4	long		prerequisite #2
    4	long		prerequisite #3
    4	long		prerequisite #4
    4	long		flags (binary):
								00000000
			enables diplomats			.......1
			enables irrigation without fresh water	......1.
			enables bridges				.....1..
			disables diseases from flood plains	....1...
			enables conscription of units		...1....
			enables mobilization levels		..1.....
			enables recycling			.1......
			enables precision bombing		1.......

			enables mutual protection pacts		.......1
			enables right of passage treaties	......1.
			enables military alliances		.....1..
			enables trade embargoes			....1...
			doubles effect of (wealth) improvement	...1....
			enables trade over sea tiles		..1.....
			enables trade over ocean tiles		.1......
			enables map trading			1.......

			enables communication trading		.......1
			not required for era advancement	......1.
			doubles work rate (of workers)		.....1..

TOP TFRM SECTION (Worker Jobs)
  4	char		"TFRM"
  4	long		number of worker jobs

  For each job:
    4	long		length of job data (112)
    32 string		worker job name
    32	string		civilopedia entry
    4	long		turns to complete 6
    4	long		required
    4	long		required resource #1
    4	long		required resource #2
    32	string		order

TOP TERR SECTION (Terrain)
  4	char		"TERR"
  4	long		number of terrains

  For each terrain:
    4	long		length of terrain data (111)
    4	long		number of possible resources
    3	byte		possible resources (binary)
			1 for the corresponding indexes of the resources
    32	string		terrain name
    32	string		civilopedia entry
    4	long		irrigation (food) bonus
    4	long		mining (shields) bonus
    4	long		road (commerce) bonus
    4	long		defense bonus
    4	long		movement cost
    4	long		food
    4	long		shields
    4	long		commerce
    4	long		worker job
    4	long		pollution effect

TOP WSIZ SECTION (World Sizes)
  4	char		"WSIZ"
  4	long		number of world sizes

  For each terrain:
    4	long		length of world size data (80)
    4	long		optimal number of cities (corruption)
    4	long		tech rate
    24	string		??? (empty)
    32	string		world size name
    4	long		height
    4	long		distance between civs
    4	long		number of civs
    4	long		width

TOP WCHR SECTION
  4	char		"WCHR"
  4	long		"number of world characteristics" (1)
  4	long		length of WCHR section (52)
  ...

TOP WMAP SECTION
  4	char		"WMAP"
  4	long		"number of world maps" (1)
  4	long		length of WMAP section (256)
  4	long		number of resources

  For each resource:
    4	long		resource occurence

  4	long		number of continents
  4	long		height
  4	long		distance between civs
  4	long		number of civs
  4	long		???
  4	long		??? (0)
  4	long		width
  4	long		??? (-1)
  ...
  4	long		map seed
  4	long		??? (binary):
					00000000
			round world     .......1
			polar ice caps	.....1..
  

TOP TILE SECTION
  4	char		"TILE"
  4	long		number of tiles (= width/2 * height)

  For each tile:
    4	long		length of tile data (22)
    2	short		river info
    4	long		resource
    1	byte		image
    1	byte		file:	0 = xtgc.pcx, 1 = xgpc.pcx, 2 = xdgc.pcx,
				3 = xdpc.pcx, 4 = xdgp.pcx, 5 = xggc.pcx,
				6 = wcso.pcx, 7 = wsss.pcx, 8 = wooo.pcx
    2	short		??? (0)
    1	byte		overlays (binary):
					00000000
			road		.......1
			railroad	......1.
			mine		.....1..
			irrigation	....1...
			fortress	...1....
			goody huts	..1.....
			pollution	.1......
			barbarian camp	1.......
    1	byte		terrain 7
    2	short		bonuses (binary):
					00000000
			bonus grassland .......1
			player start    ....1...
			snow-capped mts ...1....
			pine forest     ..1.....
    2	short		??? (-1 = nothing, 75 = barbarian camp)
    4	long		??? (-1)
    2	short		continent

TOP CONT SECTION
  4	char		"CONT"
  4	long		number of continents (water and land)

  For each continent:
    4	long		length of continent data (8)
    4	long		type (0 = water, 1 = land)
    4	long		number of tiles of continent

{end file}

Notes

1. A string must always have 0x00 as its last byte. So a 64 byte string only has place for 63 characters, followed by 0x00. Even more,the string automatically ends at 0x00, even if it appears somewhere in the middle of the originally intended string.

2. Most sections translate pretty straight-forwardly to a tab in Civ3Edit. The name in brackets is the name of the editor tab.
The sections in this file appear alphabetically ordered by their 4 character identifier.
A superfluous section, i.e. one that uses the Civ3 defaults, can be left out entirely. So for a simple map, all sections up to the WCHR section can be left out.

3. I've tried to keep the value descriptions as close as possible to those used in Civ3Edit. For explanations of the values I refer to the excellent Civ3Edit help system.

4. References to other items (e.g. items in a drop-down box or radio button list in Civ3Edit) are often done by the zero-based index number of the position of that item in its section. -1 Usually means it doesn't refer to anything (e.g. the "None" option in a Civ3Edit drop-down box). Further on, only details for data differing from this standard will be explained.

5. For data mentioned in binary, only the used bits are mentioned. When multiple bytes are being described, the data is shown grouped per byte. In that case, only the used bytes are shown, the remaining bytes are filled with zeros. In any case, for things that appear in checkboxes in Civ3Edit, 1 means it's checked, 0 means it isn't.

6. The "turns to complete" is modified by the movement cost of the terrain. The value given in this section applies to terrain with a movement cost of 2 (e.g. Forest). Terrain with a movement cost of 1 is worked in half the time, terrain with a movement cost of 3 needs 50% more turns to work.

7. A byte, split into the first 4 and the second 4 bits.
The first 4 bytes are the "real" terraintype (0 is Desert, 1 is Plains etc. BUT: Bonus Grassland, Snow-Capped Mountains and Pine Forest are NOT separate terrains, they're merely a variation on Grassland, Mountains and Forest, respectively).
The second 4 bytes are the "base filler" terrain. This is especially used for Forest, which can be placed on top of different "base filler" terrains.

Credits

Gramphos
MagForceSeven
Mercator
Nero Would
Tventano