Distant Horizons SeedGen

SeedGen calculates terrain from the seed instead of generating and then faking assets such as trees, which is the main source of its speed. The author reports 10.7x faster Overworld and 2.3x faster Nether generation for Distant Horizons versions before 3.3 Pre N, and 5.6x faster rendering at longer distances in later builds, where the speedup grows with the render distance. Structures are placed at their correct coordinates, so they line up with what the game would generate.

SeedGen is a client-side addition to Distant Horizons and is not an alternative to it: the addon requires Distant Horizons and does not replace it. It is compatible with single noise based terrain generation mods and, from version 0.7.0, with custom structure mods. Version 0.8.0 adds faster server generation. Once an area has been explored, Distant Horizons saves its terrain normally. Multiplayer is slower because of Distant Horizons' native network restrictions. Credit for the underlying work goes to the Distant Horizons team.

The mod targets the client, and the server may run it as well for faster generation there. Distant Horizons remains the renderer, so SeedGen works alongside its saved terrain and its generator.