Experience points (XP) are an abstract measure of the experience, knowledge, and training that a player character (PC) gains while adventuring. They are usually gained from defeating monsters and completing quests, with some modules also granting experience for various other achievements, such as using skills or exploring new areas. Experience points themselves do not directly affect gameplay* but are instead the sole factor that determines when character levels can be taken. It takes 1,000 XP times a PC's current level to reach the next level; see level progression for a table.
* In a few cases, some details of gameplay depend on earned levels, rather than taken levels. In this sense, experience points can directly affect gameplay, but only to the extent that they determine character level.
The formula used for monster XP awards is, according to BioWare, quite complicated, and though based on the Dungeons & Dragons system, it takes into consideration many factors. The major factors are that tougher (higher challenge rating) monsters are worth more XP, tougher (higher level) PCs receive less XP (unless effective character level alters this), and larger parties (including associates) receive less XP per PC. Some of this information is retrieved by the engine from the data files
Playtesting has revealed that the formula for the standard XP awarded for killing creatures appears to be
(base XP * XP scale) * (multiclass penalty * party size penalty)
rounded down to an integer, where
- the base XP is retrieved from
xptable.2da— with the row being the PC's earned character level (which may be more than the levels actually taken) and the column being the enemy's challenge rating;
- the XP scale is multiplied by 10 then treated as a percentage (so "10" means "100%");
- the multiclass penalty is expressed as 100%, 80%, or 60% (rather than as the amount lost); and
- the party size penalty is 4 / (3 + party size).
The first two factors are controlled by the module builder, while the latter two are under the control of players. In the original campaign the challenge rating is further modified by a bonus from the effective character level.
Example: An elven druid 5 / sorcerer 1 has two henchmen, a familiar, an animal companion, a summoned creature, and a dominated creature. This character now suffers an 80% multiclass penalty and a 4/10 party size penalty and will only gain 0.8 * 0.4 = 32% of the module's base XP for kills.
|Party size||no penalty||20% penalty||40% penalty|
- Forum post by Georg Zoeller in BioWare's Neverwinter Nights forum "Archives: Builders - NWN Scripting", 03 April 2004.