Manual:Game Mechanics/Skills

Skills

It seems skill (spells et. al) checks got kind of lost in the mists of time. Here is the general idea:

Skills are all in [0..250]. Generally [0..100] for players.

Players have a complete skill tree. NPCs have no skills, instead either an ability or their level is used based on the skill. As a rule of thumb a player's skill should roughly equal the player's level * 2 [??]. So a level 20 player should generally have a 40 [??] swim skill (some more, some less). An NPC would generally have a skill of 1 per level, often an ability is used in place of a skill.

Skill checks are rolled open-ended 1d100.

A general purpose table of the meaning of a skill level:

  0: You're completely incompetent. No idea how to perform this skill. You might even panic.
 40: An average person's skill (real world), for example an average swimmer
100: is the best (real world) human skill. 
200: is beyond what a human being could normally achieve, we're perhaps in the divine skill territory here.

A general purpose table of a skill difficulty (e.g. how difficult are the swimming conditions):

Note that a char with a skill of N will fail half the time when the difficulty is N.

Swim Skill

Let's use swim as an example. A characters proficiency in swim in 0..100. The table below is a rough translation of a swimming skill.

  0: You'll risk drowning in shallow water even if your feet can touch the bottom. 
 40: An average (real world) swimmer
100: is the best human swimmer in the (real) world. 
200: is the most divine swimmer.

Now imaging having swim in average conditions. If your skill is average (50) then the skill check is to see the result of (1d100 + skill) - 100. If the result is above 0 the swim was a success. Therefore if your skill is 0 you always fail an average swim roll is > 100. If your skill is 75 for an average swim, you succeed 75% of the time. If your skill is 100 then you always succeed. Remember that the open-ended roll can of course always offset even a sure success or fail.

A room's swim difficulty could be:

   0: Super easy. 
   .
   .
 100 A super difficult swim. It would mean even the (real world's) best swimmer would fail half the time under these circumstances. Players with 200 skill succeed always (except OE).
 150 The world's best swimmer would 

A character that fails a skill check might be swallowing water if the fail is [0..-20]. And might take one hp damage per 10 failure if the result is worse than -20.

The function skillcheck() captures precisely this setup.

flee

For a skill like flee, the difficulty could be an expression of the character's and opponent levels compared.

 +5: For each level better than the opponent
  0: Same level, no modifier
 -5; For each level worse than the opponent

So a level 5 PC fighting a level 1 rabbit gets a +40 bonus to flee. Since an NPC does not have skills, generally its level can be used as its skill. So a level 50 NPC has a flee skill of 50.

Search

On any hidden item is a 'difficulty' rating on a scale of 0-100. It could technically go from 0-250 but that's just crazy. It is denoted in the zone file as below with X being a number between 0 and 100:

open {EX_OPEN, EX_CLOSE, EX_HIDDEN} difficulty X; 

Searching depends on the searcher's skill level in searching as well as their brain ability. Each search attempt costs 20 endurance so that the player knows something is there. The difficulty you choose for hidden exits is also the same difficulty the door would need to be if the lock were pick-able as there cannot be more than one difficulty per exit.