0 = even spread, 1 = strongly clumped into patches and clearings.
Chance (0..1) that each blue-noise point keeps an instance.
Minimum distance between instances of this entry, metres.
Species or rock preset name (e.g. 'oak', 'acacia', 'boulder').
Something scattered over a biome: a tree or plant species from
threejs-trees, or a rock preset. Placement is blue-noise withspacingmetres between instances;probabilitythins that out.