Distributions are what actually place ore in the world. There are four distribution algorithms available - StandardGen, Veins, Cloud, and Substitute - and each distribution places ore using one of these algorithms.
Distributions are defined in the config file using elements named after the intended algorithm: <StandardGen>, <Veins>, <Cloud>, and <Substitute>. Distributions are generated in the order that they appear, which is important if two distributions place/replace the same block. There is no limit to how many distributions may be placed in the config file.
In addition to regular distributions, it is possible to define distribution "Presets". These are special non-generating distributions that are used mostly as a reference for default parameters values. Presets will not place ore in the world (they are actually discarded after the config file has finished loading). Consequently, presets do not generate any an error if they don't have an Ore block specified.
What parameters are available for a distribution depends on the algorithm, but there are some parameters common to most or all algorithms:
|Name||name attribute||A name used to identify the distribution. This is used by other distributions to inherit default parameter values, for log messages, and for debugging console commands. It is recommended (but not required) that distribution names be unique and contain no whitespace.|
|Seed||seed attribute||A seed modifier for random numbers generated by this distribution. If two distributions have similar settings and the same seed, they will share the same geometry. By default each distribution is given a unique seed based on its position in the config file.|
|Ore blocks||block attribute and/or <OreBlock> elements||The ore block that the distribution will spawn. A mixture of blocks can be specified using multiple <OreBlock> elements with fractional weights.|
|Settings||<Setting> elements||Numerical parameters that are randomly chosen from a range of possible values. Each setting has an average, range, and probability function that determine how the random values are chosen.|
|Replaceable Blocks||<Replaces> elements||The block or blocks that can be replaced when spawning ore.|
|Target Biomes||<Biome> elements||The biome or biomes in which the distribution may generate.|
|Default parameter values||inherits attribute|| Attributes and settings that are not explicitly specified are "inherited" from another distribution of the same type. If inherits is specified, the hard-coded default values are used.
NOTE: Distribution names and seeds cannot be inherited.
|Child distributions||nested distribution elements|| <Veins> and <Cloud> elements may be nested inside each other. The nested distribution becomes a "child" and will only spawn within a certain horizontal distance of its parent.
Substitute distributions may neither have children nor be children themselves.