Enhancements

Overview
As a character advances in experience and level, they will gain action points (aka AP) which can then be spent on enhancements. The available enhancement selection is based upon a character's race and class, and consists of improvements to those race and class strengths. For example, a Rogue would be offered enhancements to improve skill at hiding or disarming traps, while a Barbarian would be offered enhancements to improve their ability to Rage.

Enhancements are offered via different "trees", which are a collection of thematically related enhancements:
 * Classes usually have 3 class trees each
 * Races have 1 racial tree each (n.b. Racial variants have different racial trees from each other)
 * There are several universal trees that are independent of race or class; these usually require specific favor or a special purchase to unlock

Each tree is broken into 2 parts - the core enhancements plus 4 or 5 tiers of enhancements:
 * Each successive tier offers (usually) more powerful enhancements than the one before
 * Each successive tier requires a certain number of AP to be spent on previous tiers, called progression, thus a character cannot spend all their points on the highest, most powerful tiers

Tiers also require certain character or class level:
 * Tier 1-4 enhancements require levels 1-4 respectively
 * Tier 5 enhancements require (class or character) level 12

The core enhancements work slightly differently:
 * Core enhancements have a minimum point expenditure required, but are only available once a certain class level (for class trees) or character level (for racial/universal trees) is reached
 * The Core 1 enhancement must be purchased before any AP can be spent on the Tiers, but further core abilities are purely optional

Enhancements from a class, racial or universal tree usually stack with other enhancements from other class, racial or universal trees, even when they give identical bonuses: If, however, the enhancements have identical names, they may not stack:
 * e.g. Elven Dexterity and Ranger Dexterity can be taken together
 * e.g. The Awareness enhancement is available in several trees, but only the highest Awareness bonus applies

Ability bonuses from enhancements or equipped items do not count towards enhancement or feat prerequisites.

Enhancements can be reset using platinum or astral shards while in a public area. The platinum cost is determined by the number of action points currently spent in that tree, as well as a multiplier determined by the number of enhancement resets that the character has done recently. When resetting enhancements, a character may choose to reset any tree individually or clear all trees and enhancements at once and start over entirely.

Limits
Characters are limited to enhancements from a maximum of 6 class or universal trees plus their racial tree, for a possible total of 7 active trees.

A character can only select tier 5 enhancements from one tree at any given time:
 * Both class and universal trees have 5 tiers
 * All racial trees have only 4 tiers

Action Points
Action Points (AP) are points gained throughout the process heroic levelling. A character can spend those points on enhancements. They must, however, meet the progression requirements and any prerequisites, before being able to pick the desired enhancement. Each level, a character gains an AP at ranks 1, 2, 3 and 4, for a total of four action points per heroic level. At the heroic level cap (20), there are no ranks, so the character instantly gains the last 4 AP, for a final total of 80 AP. n.b. No enhancement points are gained during epic levelling. Banking experience or levels does not grant access to additional AP past the 4 for the current level. Once a character takes their next level, however, any banked experience that results in additional ranks is immediately translated into available AP. Some enhancements cost more than one AP. For this reason, a character does not lose AP when leveling up - they can save (or bank) as many as they wish, until they choose to spend them.

Additional racial action points
In addition to the 80 AP gained from class levels, characters that have undergone Racial Reincarnation may receive additional AP that can only be spent on racial enhancements. These bonus AP are not level-gated - a character can spend them all at level 1. Characters get 1 additional AP for each non-iconic race that has undergone Racial Reincarnation 3 times (Additional reincarnations with the same race have no additional effect). As of Update 36 Patch 3, DDO has 11 non-iconic races, thus characters can get 11 extra racial AP. With the release of the Mists of Ravenloft expansion, Racial Enhancement Point Tomes can grant an additional 2 racial AP to a character.

Tips

 * In game, you can pull up your Enhancement screen at any time by hitting Ctrl + r. You can spend or respec your AP any time you are in a public area (no need to visit a trainer, but that works too).
 * At most, you can take enhancements from 6 class or special trees plus your 1 racial tree for a total of 7 trees simultaneously.
 * Spending points in one class tree might make another class tree or specific enhancement unavailable (e.g. The various Sorcerer's savant trees lock out all enhancements of the "opposite" element (fire/water, air/earth), and you cannot spend AP in both the Ranger: Arcane Archer and racial Elf/Half-Elf/Morninglord Arcane Archer trees, etc.)
 * Use the big arrows on the sides of the enhancements UI to access additional trees.
 * You can rearrange the order of your enhancement trees by dragging/dropping the round class icon at the bottom-left of each tree, or by clicking on the drop-down box near the bottom of the trees.
 * The first core enhancement (only) is required to take any other enhancements in a tree.
 * You can only take tier 5 abilities in one class tree.
 * Enhancements with the same name in multiple trees might not stack (inconsistent).

Enhancements list
Select a category from the table below for detailed information about enhancements available for that race or class.

Pre Mod 3.3
The enhancement system was totally redesigned in Mod 3.3. Before Mod 3.3, a player could only have four enhancements, however one line of enhancements only counted as one enhancement. For example, a level 10 dwarf could only select Dwarven Armor Mastery III but could not select the second nor the first and that counted as one of his four enhancements. In this era of the game, players could not save APs before leveling. In fact, if a player had unspent APs when leveling, they received a warning message. Once a character had reached the maximum level possible at that time, they received a free action point every 20,000 XP, allowing them to change their enhancements if so desired.

Post Unlimited
In Unlimited/Module 9, Capstone enhancements and Prestige enhancements were added. For each class 1 Capstone was implemented and it was announced that, for each class, 3 tiers of 3 different Prestige Enhancements were planned. For a long time, many of these Prestige Enhancements remained unavailable, limiting player choices in some classes. In Update 7, class specific enhancements (e.g. Cleric Heal I) were replaced with generalised enhancements (e.g. Improved Heal I). This change decreased costs for the four tiers of the enhancements. Prior to the change, Tiers I, II, II & IV cost 1, 2, 3 & 4 AP respectively. After the change, all tiers cost 1 AP each for generalised enhancements. This improved the viability of Prestige enhancements for many builds.

Update 19 Enhancement Pass
In Update 19, a total redesign of the user interface was implemented, changing the way AP could be spent. All enhancements, including previous Prestige enhancements and Racial enhancements, were integrated into Enhancement Trees.