Fallout engine calculations
From Vault-Tec Labs
Contents |
[edit] Stats
There are 7 basic values (stats), describing the character in Fallout. Here they are:
- Strength (ST)
- Perception (PE)
- Endurance (EN)
- Charisma (CH)
- Intelligence (IN)
- Agility (AG)
- Luck (LK)
Stats are not being calculated. Each stat can have a value between 1 and 10 inclusively. The default value for all the stats is 5. Also, a player is given 5 free points to imrpove any of these stats at start.
[edit] Skills
There are 18 skill values the character in Fallout has. Skills are being measured in percent and have a value ceiling at 300%. Each skill has its basic value that is being calculated by a formula derived from the stats. All fractional values are being rounded down. Here are these formulas:
Small guns:
35 + AG
Big guns:
10 + AG
Energy weapons:
10 + AG
Unarmed:
65 +(ST + AG) / 2
Melee weapons:
55 + (ST + AG) / 2
Throwing:
40 + AG
First aid:
50 + (PE + IN) / 2
Doctor:
30 + (PE + IN) / 2
Sneak:
45 + AG
Lockpick:
40 + (PE + AG) / 2
Steal:
40 + AG
Traps:
40 + (PE + AG) / 2
Science:
45 + 2 * IN
Repair:
40 + IN
Speech:
45 + 2 * CH
Barter:
40 + 2 * CH
Gambling:
40 + 3 * LK
Outdoorsman:
25 + (EN + IN) / 2
Every experience level up a player will get
5 + 2 * IN
skill points for skill improvements. The more value has the skill the harder it is to improve:
0% - 100% : 1% further costs 1 skill point 101% - 125% : 1% further costs 2 skill points 126% - 150% : 1% further costs 3 skill points 151% - 175% : 1% further costs 4 skill points 176% - 200% : 1% further costs 5 skill points 201% - 300% : 1% further costs 6 skill points
[edit] Tag Skills
A player must choose (tag) any 3 of the skills as their primary skills at start. Tagging adds a permanent bonus of 20% to a skill and twices its improvement score. On the experience level 21, a player can take a perk which provides a possibility to tag another one untagged skill.
[edit] Misc
There are some miscellaneous parametres for a player in Fallout that cannot be changed directly. All values must be positive or equal to zero (with the except for Healing rate and Melee damage). The misc parametres are being calculated basing on the stats as well. All fractional values are being rounded down.
Hit points:
15 + 2 * EN + ST
Armor class:
AG
Action points:
5 + AG / 2
Carry weight:
25 + 25 * ST
Melee damage:
ST - 5 * Note that this value must be greater or equal to 1.
Damage resistance:
0
Poison resistance:
5 * EN
Radiation resistance:
2 * EN
Sequence:
2 * PE
Healing rate:
EN / 3 * Note that this value must be greater or equal to 1.
Critical chance:
LK
[edit] Traits
A player must choose 2 of the 16 traits at start. All traits have both positive and negative effects. Some of the effects are concealed or not obvious and are not yet figured. Here are the known trait effects:
Fast metabolism:
Healing rate +2 Radiation and poison resistances = 0
Bruiser:
ST +2 Action Points -2
Small frame:
AG +1 Carry weight is calculated as 25 + ST * 15
One hander:
???
Finesse:
Critical chance +10% ???
Kamikaze:
Sequence +5 Armor class = 0
Heavy handed:
Melee damage +4 ???
Fast shot:
-1 action point required to fire Aimed shots are disabled
Bloody mess:
People die with their bloodiest death animations ? ???
Jinxed:
Raised critical miss chance for enemies ? Raised critical miss chance for you ?
Good natured:
+15 first aid, doctor, speech and barter -10 small guns, big guns, energy weapons, unarmed, melee weapons and throwing
Chem reliant:
Addiction time shortened ? Addiction trend broaded ?
Chem resistant:
Addiction time extended ? Addiction trend dimmed ?
Sex appeal:
Sex appeal value raised ? No obvious penalties Used in many script checks
Night person:
+1 PE and AG at night -1 PE and AG during daylight * Unused in Fallout2
Skilled:
+10 all skills Perk gain every 4 levels
Gifted:
+1 all stats -10 all skills, -5 skill points gain every level
[edit] Perks
Awareness
See detailed critter information (current HP, weapon).
Bonus HtH Attacks
-1 AP for HtH and melee attacks.
Bonus HtH Damage
+2 Melee damage per rank (3)
Bonus Move
+2 AP that can only be used for movement per rank (2)
Bonus Ranged Damage
+2 ranged damage per rank (2)
Bonus Rate of Fire
-1 AP for ranged weapons
Earlier Sequence
+2 Sequence per rank (3)
Faster Healing
+2 healing rate per rank (3)
More Criticals
+5% critical chance per rank (3)
Night Vision
Reduces darkness level?
Presence
Improves NPC reactions?
Rad Resistance
+10% radiation resistance per rank (3) [Fallout 1] +15% radiation resistance per rank (2) [Fallout 2]
Toughness
+10% to normal damage resistance per rank (3)
Strong Back
+50 carry weight per rank (3)
Sharpshooter
+2 PE when determining chance to hit?
Silent Running
Can run while sneaking.
Survivalist
+25 to Outdoorsman skill per rank (3)
Master Trader
Improves barter modifiers?
Educated
+2 skill points per level per rank (3)
Healer
First Aid and Doctor heal 4-10 more HP per rank (2)
Fortune Finder
More money found in random encounters?
Better Criticals
Better critical hit effects.
Empathy
See NPC's reactions to dialogue options.
Slayer
Melee attacks are critical hits if Luck check is passed.
Sniper
Ranged attacks are critical hits if Luck check is passed.
Silent death
Cause double damage if you hit a critter in the back while sneaking.
Action Boy
+1 AP per rank (2)
Mental Block
Not affected by the Master's psychic attacks [Fallout 1 only]
Lifegiver
+4 additional HP per level per rank (2)
Dodger
+5 AC
Snakeeater
+25% poison resistance per rank (2)
Mr. Fixit
+10 to Repair and Science skills
Medic
+10 to First Aid and Doctor skills
Master Thief
+15 to Lockpick and Steal skills
Speaker
+20 to Speech skill
Heave Ho!
+2 ST for determining throwing range per rank (3)
Pickpocket
Removes size and facing penalties when stealing.
Ghost
+20 to Sneak skill in dark areas
Cult of Personality
Karma modifiers are always positive
Scrounger
More ammo in random encounters [Fallout 1 only]
Explorer
More special encounters?
Flower Child
? [Fallout 1 only]
Pathfinder
Traveling on the world map takes 25% less time per rank (2)
Animal Friend
Won't be attacked by animals [Fallout 1 only]
Scout
More special encounters?
Mysterious Stranger
An ally sometimes appears in random encounters
Ranger
+15 to Outdoorsman skill
Quick Pockets
-1 AP to open inventory per rank (2) [Fallout 1] -2 AP to open inventory [Fallout 2]
Smooth Talker
+1 IN for determining dialogue options
Swift Learner
+5% more experience points per rank (3)
Tag!
Choose a fourth tag skill
Mutate
Remove a trait and choose another to take its place
Gecko Skinning
Can skin dead geckos
Dermal Impact Armor
+5% to normal and explosive DR
Dermal Impact Assault Enhancements
+10% to normal and explosive DR -1 CH
Phoenix Armor Implants
+5% to laser, fire, and plasma DR [possibly electrical and EMP?]
Phoenix Assault Enhancements
+10% to laser, fire, and plasma DR [possibly electrical and EMP?] -1 CH
Vault City Inoculations
+10% to poison and radiation resistance
Adrenaline Rush
+1 ST if below 50% HP
Cautious Nature
+3 PE for determining random encounter placement
Comprehension
+50% more skill points gained from reading books
Demolition Expert
Explosives cause more damage, always go off on time
Gambler
+20 to Gambling skill
Gain Strength
+1 ST
Gain Perception
+1 PE
Gain Endurance
+1 EN
Gain Charisma
+1 CH
Gain Intelligence
+1 IN
Gain Agility
+1 AG
Gain Luck
+1 LK
Harmless
+20 to Steal skill
Here and Now
Gain another level immediately
HtH Evade
If both item slots are empty or contain unarmed-class weapons, at the end of a combat round AC increases by 2 per unused AP, plus 1/12 your Unarmed skill
Kama Sutra Master
Better sex rating
Karma Beacon
Improves karma modifiers
Light Step
Reduces chance to set off traps
Living Anatomy
+10 to Doctor skill +5 damage to living critters
Magnetic Personality
Can have one more NPC (maximum of 5)
Negotiator
+10 to Speech and Barter skills
Pack Rat
+50 to carry weight
Pyromaniac
+5 damage with fire weapons
Quick Recovery
Only takes 1 AP to stand up
Salesman
+20 to Barter skill
Stonewall
Less likely to be knocked down
Thief
+10 to Sneak, Lockpick, Steal, and Traps skills
Weapon Handling
+3 ST when determining if a weapon can be used
Vault City Training
+5 to Doctor and First Aid skills
Alcohol Raised Hit Points
+2 max HP
Alcohol Raised Hit Points II
+4 max HP
Alcohol Lowered Hit Points
-2 max HP
Alcohol Lowered Hit Points II
-4 max HP
Autodoc Raised Hit Points
+2 max HP
Autodoc Raised Hit Points II
+4 max HP
Autodoc Lowered Hit Points
-2 max HP
Autodoc Lowered Hit Points II
-4 max HP
Expert Excrement Expeditor
+5 to Speech skill
[edit] Damage and combat calculations
Work in progress.
This is first version of damage calculation in Fallout2:
Dmg_:=Trunc(Dmg_w*(Dmg_mod_1/Dmg_mod_2)-DT_armor)-Trunc(Trunc(Dmg_w*(Dmg_mod_1/Dmg_mod_2)-DT_armor)*(DR_armor+DR_mod_ammo))
here is: Dmg_w - weapon base damage (average from min & max damage) Dmg_mod_1 oraz Dmg_mod_2 - ammo Damage modificators DR_mod_ammo - ammo Damage Resistance (% as 0,01)
DT_armor - armor Damage Treshold DR_armor - armor Damage Resistance (% as 0,01)
Results are truncated by function [trunc] to integer.
Example
Desert Eagle: min_dmg = 10 | | avg_dmg = (10+16)/2= 13 max_dmg = 16 |
JHP ammo: 2/1 20% Dmg_mod_1 = 2 Dmg_mod_2 = 1 DR_mod_ammo = 20% = 0,20
armor Metal Armor: 4/30% DT_armor = 4 DR_armor = 30% = 0,30
Result:
Dmg_:= =Trunc(13*2/1-4)-Trunc(Trunc(13*2/1-4)*(0,30+0,20))=Trunc(26-4)-Trunc(Tunc(26-4)*0,5)=22-Trunc(22*0,5)=22-11=11
For ammo type FMJ: 1/1 -20% result is:
Dmg_:= =Trunc(13*1/1-4)-Trunc(Trunc(13*1/1-4)*(0,30+(-0,20)))=Trunc(13-4)-Trunc(Tunc(13-4)*0,1)=9-Trunc(9*0,1)=9-0=9
So we have such results for Metal Armor:
ammo JHP - 11 dmg ammo AP - 9 dmg
End.
Other description of damage alghoritm in Fallout2:
the formula for calculating damages is:
(((base_damage*dam_mult/dam_div)/2)*cbt_diff_mod)/100-dmg_tresh-(((((base_damage*dam_mult/dam_div)/2)/cbt_diff_mod)/100-dmg_tresh)*ammo_dr_adj)/100
base_damage is a random number in range of weapon damages plus an eventual bonus if you have a bonus for ranged attack and you're using a ranged weapon (the bonus is equal to 2* the level of the perk).
dam_mult is the damages multiplier from the weapon's ammo plus another value passed to the function. This value is almost always 2, I suspect it only changes when you make a critical hit.
dam_div is the damages diviser from the ammo.
cbt_diff_mod is changed by difficulty level: always 100 when the player attacks 75 if playing wimpy 100 if playing normal 125 if playing rough
dmg_tresh is the target'sz damage treshold for the type of damages it concerns.
ammo_dr_adj is the ammo DR adjustement.
Thought it's not definitive, I may have missed something, I'll have to double check.
Some damages can be added after this with the living anatomy perk and the pyromaniac perk.
