Vault-Tec Labs

GCD files contain starting character profiles. For more details, see "Resource Handling", section "Premade characters".

In addition to the 'theme' characters combat.gcd, stealth.gcd and diplomat.gcd, there are thee other files: demo.gcd, blank.gcd and player.gcd.

Demo.gcd was used in the demo, and blank.gcd and player.gcd were intended for creating our own characters (recall at the beginning of the game choosing the button "create character"). However, none of these files are used in the game.

GCD File Format

All offsets are listed in this table:

Offset Meaning Normal Range
Game flags
0x0000 This part is not fully understood, but includes indicating some of the status tags shown in the lower-left part of the screen. It's known that 0x00000001 - "sneak", 0x00000008 - "level", 0x00000010 - "addict". The tags for "poisoned" and "radiated" are not here. -
Primary stats
0x0004 Strength (ST) 0 to 10
0x0008 Perception (PE) 0 to 10
0x000C Endurance (EN) 0 to 10
0x0010 Charisma (CH) 0 to 10
0x0014 Intelligence(IN) 0 to 10
0x0018 Agility (AG) 0 to 10
0x001C Luck (LK) 0 to 10
Secondary stats
0x0020 Hit Points * 0 to 999
0x0024 Action Points * 0 to 999
0x0028 Armor Class * 0 to 999
0x002C Unarmed Damage (NOTE: this is not used by the game! Melee Damage stat is used instead.) -
0x0030 Melee Damage * 0 to 999
0x0034 Carry Weight * 0 to 999
0x0038 Sequence * 0 to 99
0x003C Healing Rate * 0 to 99
0x0040 Critical Chance * 0 to 100
0x0044 Critical hit modifier * 0 to 100
0x0048 Damage Threshold - normal 0 to 999
0x004C Damage Threshold - laser 0 to 999
0x0050 Damage Threshold - fire 0 to 999
0x0054 Damage Threshold - plasma 0 to 999
0x0058 Damage Threshold - electrical 0 to 999
0x005C Damage Threshold - EMP 0 to 999
0x0060 Damage Threshold - explosive 0 to 999
0x0064 Damage Resistance - normal 0 to 100
0x0068 Damage Resistance - laser 0 to 100
0x006C Damage Resistance - fire 0 to 100
0x0070 Damage Resistance - plasma 0 to 100
0x0074 Damage Resistance - electrical 0 to 100
0x0078 Damage Resistance - EMP 0 to 100
0x007C Damage Resistance - explosive 0 to 100
0x0080 Radiation Resistance * 0 to 100
0x0084 Poison Resistance * 0 to 100
0x0088 Age 0 to 35
0x008C Gender 1 - female, 0 - male.
Bonuses to primary stats
0x0090 Bonus to strength 0 to 10
0x0094 Bonus to perception 0 to 10
0x0098 Bonus to endurance 0 to 10
0x009C Bonus to charisma 0 to 10
0x00A0 Bonus to intelligence 0 to 10
0x00A4 Bonus to agility 0 to 10
0x00A8 Bonus to luck 0 to 10
Bonuses to secondary stats
0x00AC Bonus HP 0 to 999
0x00B0 Bonus AP 0 to 999
0x00B4 Bonus AC 0 to 999
0x00B8 Bonus to unarmed damage (NOTE: this is not used by the game! Melee Damage stat is used instead.) -
0x00BC Bonus to melee damage 0 to 999
0x00C0 Bonus to carry weight 0 to 999
0x00C4 Bonus to sequence 0 to 99
0x00C8 Bonus to healing rate 0 to 99
0x00CC Bonus to critical chance 0 to 100
0x00D0 Bonus to critical hit modifier 0 to 100
0x00D4 Bonus to DT (normal) 0 to 999
0x00D8 Bonus to DT (laser) 0 to 999
0x00DC Bonus to DT (fire) 0 to 999
0x00E0 Bonus to DT (plasma) 0 to 999
0x00E4 Bonus to DT (electrical) 0 to 999
0x00E8 Bonus to DT (EMP) 0 to 999
0x00EC Bonus to DT (explosive) 0 to 999
0x00F0 Bonus to DR (normal) 0 to 100
0x00F4 Bonus to DR (laser) 0 to 100
0x00F8 Bonus to DR (fire) 0 to 100
0x00FC Bonus to DR (plasma) 0 to 100
0x0100 Bonus to DR (electrical) 0 to 100
0x0104 Bonus to DR (EMP) 0 to 100
0x0108 Bonus to DR (explosive) 0 to 100
0x010C Bonus to radiation resistance 0 to 100
0x0110 Bonus to poison resistance 0 to 100
0x0114 Bonus to age 0 to 35
0x0118 Bonus to gender (sex-change surgery is still available in the post-nuclear world, it seems) Positive values - female, negative or zero - male
0x011C Small Guns 0 to 300-(5+4*AG)
0x0120 Big Guns 0 to 300-(2*AG)
0x0124 Energy Weapons 0 to 300-(2*AG)
0x0128 Unarmed 0 to 300-(30+2*(ST+AG))
0x012C Melee Weapons 0 to 300-(20+2*(ST+AG))
0x0130 Throwing 0 to 300-(4*AG)
0x0134 First Aid 0 to 300-(2*(PE+IN))
0x0138 Doctor 0 to 300-(5+PE+IN)
0x013C Sneak 0 to 300-(5+3*AG)
0x0140 Lockpick 0 to 300-(10+PE+AG)
0x0144 Steal 0 to 300-(3*AG)
0x0148 Traps 0 to 300-(10+PE+AG)
0x014C Science 0 to 300-(4*IN)
0x0150 Repair 0 to 300-(3*IN)
0x0154 Speech 0 to 300-(5*CH)
0x0158 Barter 0 to 300-(4*CH)
0x015C Gambling 0 to 300-(5*LK)
0x0160 Outdoorsman 0 to 300-(2*(EN+IN))
0x0164-0x016F Unknown. These values are always zero. -
0x0170-0x018F Character name 0 to 32 characters, padded with zeroes
0x0190 First tagged skill 0 to 17
0x0194 Second tagged skill 0 to 17
0x0198 Third tagged skill 0 to 17
0x019C Fourth tagged skill  (This stays default value unless GCD was edited manually outside of the game.) 0 to 17, default is FF FF FF FF
0x01A0 First trait 0 to 15
0x01A4 Second trait 0 to 15
0x01A8 Character points (for stats) 0 to 70-(ST+PE+EN+CH+IN+AG+LK)


1. All offsets point to "big endian" DWORDs (4-byte numbers, lowest value = 4th byte).

2. Some values can be set higher than the maximum (SPECIAL, for example), but starting a game with them won't work. (not sure if this means an error/crash, or not having further effect beyond the max.)

3. Not all the maximum values have been verified; some are based on (fairly reasonable) assumptions.

4. When setting maximum values, remember that traits can affect stats and skills, and primary stats affect skills and secondary stats.

5. Those marked "presumably" are based on comparison with the SAVE.DAT file format (and also from studying PRO files).

6. Asterisks (*) mark secondary stats which are calculated based on primary stats and are not loaded from the GCD. I.e. they are here only nominally, and are not actually used.

7. If you tagged a fourth skill, the number of additional tag skill points becomes 99 (the default is 3, as you may recall). However, it's not possible to tag all the skills, because the restriction to three tagged skills remains.

If you play on a Mac, you can use the grammar on  to edit .gcd files easily.

Original document at (in russian)