Editing GURPS (section)

==Mechanics of the game==

===Character points===
A character in ''GURPS'' is built with [[character point]]s. For a beginning character in an average power game, the 4th edition suggests 100&ndash;150 points to modify attribute stats, select advantages and disadvantages, and purchase levels in skills. Normal [[Non-player character|NPCs]] are built on 25–50 points. Full-fledged heroes usually have 150&ndash;250 points, while superheroes are commonly built with 400&ndash;800 points.<ref name="rpgnet2">{{Cite web |last=Smith |first=Eli |date=2004-10-11 |title=GURPS Fourth Edition Basic Set Review |url=http://www.rpg.net/reviews/archive/10/10731.phtml |access-date=2008-12-08 |publisher=RPGNet.com |type=review}}</ref> The highest point value recorded for a canon character in a ''GURPS'' sourcebook is 10,452 for the Harvester (p.&nbsp;88) in ''[[GURPS Monsters]]''.<ref>{{Cite book |last=Johnson |first=Hunter |url=http://www.sjgames.com/gurps/books/monsters/ |title=GURPS: Monsters |publisher=[[Steve Jackson Games]] |year=2002 |isbn=1-55634-518-6 |edition=3rd |pages=128}}</ref>

In principle, a Game Master can balance the power of foes to the abilities of the player characters by comparing their relative point values.

===Attributes===
Characters in ''GURPS'' have four basic [[attribute (role-playing games)|attribute]]s:

* '''Strength (ST)''': A measure of the character's physical power and bulk, ability to lift, carry, and do damage
* '''Dexterity (DX)''': A measure of the character's physical agility, coordination, and manual dexterity
* '''Intelligence (IQ)''': A measure of the character's mental capacity, acuity and sense of the world
* '''Health (HT)''': A measure of the character's physical stamina, recovery speed, energy and vitality, ability to resist disease

Each attribute has a number rating assigned to it. Normally they begin at 10, representing typical human ability, but can go as low as 1 for nearly useless, to 20 (or higher) for superhuman power. Anything in the 8 to 12 range is considered to be in the ''normal'' or ''average'' area for humans. Basic attribute scores of 6 or less are considered ''crippling''—they are so far below the human norm that they are only used for severely handicapped characters. Scores of 15 or more are described as ''amazing''—they are immediately apparent and draw constant comment.

Players assign these ratings spending [[character point]]s. The higher the rating the more points it will cost the player, however, assigning a score below the average 10 gives the player points back to assign elsewhere. Since almost all skills are based on Dexterity or Intelligence, those attributes are twice as expensive (or yield twice the points, if purchased below 10). In earlier editions (pre–4th Edition) all attributes followed the same cost-progression, where higher attributes cost more per increase than attributes close to the average of 10.

Attribute scores also determine several ''secondary characteristics''. The four major ones are each directly based on a single attribute:

*'''Hit Points (HP)''': how much damage and injury can be sustained, based on ''ST'' in 4e. In previous editions it was based on HT.
*'''Will (Will)''': mental focus and strength, withstanding stress, based on ''IQ''.
*'''Perception (Per)''': general sensory alertness, based on ''IQ''.
*'''Fatigue Points (FP)''': a measure of exertion, tiredness, and hunger, based on ''HT'' in 4e. In previous editions it was based on ST.

The other secondary characteristics (Damage<!--(thrust/swing)-->, Basic Lift<!--[in lbs]-->, Basic Speed, Dodge, <!--Basic -->Move<!--(Ground/Water/Air) [in yard/sec]-->) are calculated from one or more attribute values using individual [[Mathematical table|table]]s or [[formula]]e.

=== Character advantages and disadvantages ===
''GURPS'' has a profusion of advantages and disadvantages which enable players or Game Masters to customize their characters. The myriad options available and the rewards the system provides players for carefully creating their characters are attractive to gamers who enjoy a high degree of flexibility in character design.

A player can select numerous Advantages and Disadvantages to differentiate the character; the system supports both mundane traits (such as above-average or below-average Wealth, Status and Reputation) as well as more exotic special abilities and weaknesses. These are categorized as physical, mental or social, and as exotic, supernatural, or mundane. Advantages benefit the character and cost points to purchase. Selecting Disadvantages returns character points and allows players to limit their characters in one way in exchange for being more powerful or gifted in other areas. Disadvantages include such positive attributes as honesty and truthfulness which limit the way a character is played. There are also many Perks and Quirks to choose from which give a character some personality. Perks (minor Advantages) and Quirks (minor Disadvantages) benefit or hinder the character a bit, but they mostly add role-playing flavor.

Enhancements and limitations can tailor an advantage or disadvantage to suit creative players. These modify the effects and point cost of advantages and disadvantages. For example, to create a "dragon's breath" attack, a player would select the Innate Attack ability (the ability that allows a player to perform an attack most humans could not), and select burning attack 4D (normally 20 points). Then, the player would modify it as follows: cone, 5 yards (+100%); limited use, 3/day (-20%); reduced range, x1/5 (-20%). The final percentage modifier would be +60%, making the final cost 32 points. This addition to the system greatly increases its flexibility while decreasing the number of specific advantages and disadvantages that must be listed. Finally, ''mitigators'' can themselves tailor advantages and disadvantages (see ''[[GURPS Bio-Tech]]'' for such an example).

===Skills===
''GURPS'' has a wide variety of [[skill (role-playing)|skill]]s intended to enable it to support any conceivable genre (such as [[Acrobatics]] and Vehicle Piloting). Each skill is tied to at least one attribute, and the characters' abilities in that skill is a function of their base attributes + or - a certain amount.

The availability of skills depends on the particular genre in which the ''GURPS'' game is played. For instance, in a generic [[medieval]] [[fantasy]] setting, skills for operating a [[computer]] or flying a [[Fighter aircraft|fighter jet]] would not normally be available. Skills are rated by level, and the more levels purchased with character points, the better the characters are at that particular skill relative to their base attribute.

Skills are categorized by difficulty: Easy, Average, Hard, and Very Hard. Easy skills cost few points to purchase levels in, and the cost per skill level increases with each level of difficulty. Game mechanics allow that eventually it may be less expensive to raise the level of the base attribute the skills depend on as opposed to purchasing higher levels of skills. Players can generally purchase a skill for their characters at any level they can afford. The lower a player chooses, the fewer points it costs to buy the skill, while higher levels cost more points. Some skills have default levels, which indicate the level rating a character has when using that skill untrained (i.e. not purchased). For example, a character with a Dexterity of 12, is using the Climbing skill untrained. Climbing has a default of DX-5 or ST-5, which means that using the skill untrained gives him a Climbing skill level of 7 (12–5) if he tied it to the Dexterity stat. If the character had a higher Strength stat, he could have a better chance of success if he tied the Climbing skill there instead.

Some skills also have a Tech Level (TL) rating attached to them, to differentiate between Skills that concern similar concepts, but whose tasks are accomplished in different ways when used with differing levels of technology. This helps during time traveling scenarios, or when characters are forced to deal with particularly outdated or advanced equipment. For instance, a modern boat builder's skills will be of less use if he is stuck on a desert island and forced to work with primitive tools and techniques. Thus, the skills he uses are different when in his shop (Shipbuilding/TL8) and when he is on the island (Shipbuilding/TL0).

===Success rolls===
''GURPS'' uses six-sided [[dice]] for all game mechanics using [[dice notation|standard dice notation]]. An [[Median|"average roll"]] of three six sided dice generates a total of 10.5; this makes an "average" skill check (a skill of 10, based on an unmodified attribute) equally likely to succeed or fail.

Making statistic and skill checks in ''GURPS'' is the reverse of the mechanics of most other RPGs, where the higher the total of the die roll, the better. ''GURPS'' players hope to roll as low as possible under the tested statistic's rating or skill's level. If the roll is less than or equal to that number, the check succeeds. There is no "target number" or "difficulty rating" set by the Game Master, as would be the case in many other RPG systems. Instead the GM will apply various modifiers to add or subtract to the skill level. In this way, positive modifiers increase the chance for success by adding to the stat or skill level the player must roll under while negative modifiers deduct from it, making things more difficult.

For example: a player makes a pick pocketing test for her character. The character has a Pickpocket skill with a level of 11. Under normal circumstances - i.e., under an ''average stressful situation'', according to the manual - the player must roll an 11 or less for the character to succeed. If the player rolls above 11, then the character has failed the attempt at pick pocketing.

There are some exceptions for very high or low rolls, deemed [[Critical hit|criticals]]. No matter the level of the skill, a die roll of 18 is always a ''critical failure'', and a roll of 3 or 4 is always a critical success (a roll of 17 is a critical failure as well, unless the character relevant skill level is 16 or more). The Game Master may decide in such cases that, in first case (a roll of 18, or 10+ over the modified skill level), the character has failed miserably and caused something disastrous to happen or, in the other case, that he or she succeeds incredibly well and gains some benefit as a result.

===Combat===
Combat in ''GURPS'' is organized in personal turns: i.e., every character gets a turn each [[second]], and during a character's turn he or she may take an action, such as attack or move. After all characters have taken their action, one second has elapsed. Free actions are simple actions that can be done at any time. Characters in a party have a set initiative that is entirely based upon their Basic Speed characteristic.<ref name="rpgnet3">{{Cite web |last=Chu-Carroll |first=Mark |date=2004-11-17 |title=GURPS Fourth Edition Characters Review |url=http://www.rpg.net/reviews/archive/10/10646.phtml |access-date=2008-12-08 |website=website |publisher=RPGNet.com |type=review}}</ref>

There are two kinds of attacks: Melee (possibly with hand-to-hand weapons, or unarmed combat) and Ranged (bows, guns, thrown weapons, some Innate Attacks, etc.). Attacks made by a character are checked against their skill with the particular weapon they carry. For instance, if a character is using a pistol, as with any other skill, it is beneficial to have a high level in the [[Gun]]s skill. Like any other skill check, a player must roll equal to or less than the level of the skill to succeed. Failure means a miss, success scores a hit. Similarly, critical hits mean that the blow might inflict significantly more damage to its target; critical misses may lead to a rather unpleasant and unexpected event (such as dropping the weapon or hitting the wrong target). Attack modifiers are set by the GM when factoring in things like distance, speed and cover that make a successful strike more difficult.

After a successful attack, except in the case of a critical hit, the defender usually gets a chance to avoid the blow. This is called an Active Defense, and takes the form of a Dodge (deliberate movement out of the perceived path of the attack), Parry (attempt to deflect or intercept the attack with a limb or weapon), or Block (effort to interpose a shield or similar object between the attack and the defender's body). Unlike many RPG systems, an Active Defense is an unopposed check, meaning that in most cases, the success of an attack has no effect on the difficulty of the defense. Dodge is based on the Basic Speed characteristic, while Parry and Block are each based on individual combat skills, such as Fencing, Karate, or Staff for Parry, and Shield or Cloak for Block. A common criticism is that characters can achieve a relatively high Active Defense value, drawing out fights considerably. The only mechanic within the system to address this is the Feint action, which if successful will place the adversary in an unfavorable position, reducing their active defense against that character only, on the subsequent turn.

Skills, advantages, and equipment, can be combined to great effect. For example, a gunslinger from the Old West is facing a foe: 
* the Combat Reflexes advantage gives a +1 on Fast-Draw attempts and prevents the gunslinger from being stunned into inaction during a surprise attack; 
* a successful Fast-Draw(Pistol) skill roll grants the results of the Ready maneuver instantly; 
* the Gunslinger advantage grants the character the benefits of the Aim maneuver instantly; 
* the Dual-Weapon Attack(Pistol) technique allows the gunslinger to fire both his guns at once without the -4 penalties.
* the Ambidextrous advantage or the Off-Hand Weapon Training Technique eliminates the -4 penalty for the weapon in the "off" hand.
If the gunslinger lacked these advantages, skills, and techniques, then readying, aiming, firing, aiming again, and firing again would take at least 5 seconds. If the gunslinger lacked these traits and tried to shoot two pistols at once:
* it would take 1 second to ready the pistols
* the right hand pistol would be fired with a -4 penalty
* the "off" hand pistol would be fired with a -8 penalty
* both attacks would lack the accuracy bonus from the aiming maneuver.

===Damage and defenses===
Damage from muscle-powered weapons, (clubs, swords, bows, etc.) is calculated based on the character's ST rating. The weaker a character is physically, the less damage he or she is capable of inflicting with such a weapon. Purely mechanical weapons (guns, beam sabers, bombs, etc.) have a set damage value.

When damage is inflicted upon characters, it is deducted from their [[Hit point|Hit Points]], which are calculated with the Strength stat (prior to ''GURPS'' 4th Edition, Hit Points were derived from the Health stat). Like most other RPGs, a loss of hit points indicates physical harm being inflicted upon a character, which can potentially lead to death. ''GURPS'' calculates shock penalties when someone is hit, representing the impact it causes and the rush of pain that interferes with concentration. Different weapons can cause different 'types' of damage, ranging from crushing (a club or mace), impaling (a spear or arrow), cutting (most swords and axes), piercing (bullets), and so on.

One peculiarity about loss of Hit Points is that in GURPS, death is not certain. While a very high amount of total HP loss will cause certain death, there are also several points at which a player must successfully roll HT, with different grades of failure indicating character death or a mortal injury.

Depending on the nature of the attack, there will sometimes be additional effects.

===Advancement===
Character advancement follows the same system as character creation. Characters are awarded character points to improve themselves at regular intervals (usually at the end of a game session or story).

GMs are free to distribute experience as they see fit. This contrasts with some traditional RPGs where players receive a predictable amount of experience for defeating foes. The book recommends providing 1-3 points for completing objectives and 1-3 points for good role-playing per game session.

Advancement can also come through study, work, or other activities, either during game play or between sessions. In general, 200 hours of study equals one character point which can be applied for the area being studied. Self-study and on the job experience take more time per character point while high tech teaching aids can reduce the time required.

Some intensive situations let a character advance quickly, as most waking hours are considered study. For instance, characters travelling through the Amazon may count every waking moment as study of jungle survival, while living in a foreign country could count as eight hours per day of language study or more.